feat: filter connection VLANs by group

.gitignore

@@ -4,4 +4,5 @@ __pycache__/
 .ruff_cache/
 build/
 dist/
+.testvenv/
 *.egg-info/

README.md

@@ -1,23 +1,42 @@
 # NetBox Utilities
 
-Plugin für **NetBox 4.6.5** mit acht Funktionen:
+Plugin für **NetBox 4.6.5 bis 4.6.8** mit zwölf Funktionen:
 
 - Jeder Benutzer kann die Menüs der linken Navigation verschieben oder ausblenden.
 - Ein Dropdown in der Kopfleiste setzt einen sitzungsweiten Filter für einen Mandanten oder eine Mandantengruppe.
 - Optional verpflichtende Mandantenzuordnung für alle mandantenfähigen Objekte.
 - Automatische Vorbelegung von Mandant und Mandantengruppe aus dem Objekt- oder Filterkontext.
 - Automatische 1:1-Verknüpfung von Front- und Rearports auf Geräten mit der Rolle `Patchpanel`.
+- Geräte mit optionaler Teilbreite können sich dieselbe Höheneinheit teilen.
+- Die Rack-Ansicht von MrBlakes optionalem Topology-Views-Plugin stellt Teilbreitengeräte korrekt dar.
 - Mehrere Bilder in einem Schritt im Bilder-Tab eines Objekts hochladen.
 - Mehrere Module desselben Typs in einem Schritt in freie Modulschächte einbauen.
 - Optionale Mehrfachspeicherung für verschobene Geräte aus NetBox Reorder Rack.
+- Rackbreiten bleiben beim optionalen NetBox-Export und -Import erhalten.
+- Kabel- und Funkverbindungen können direkt einem oder mehreren VLANs zugeordnet werden.
 
 Die Navigationseinstellungen sind benutzerbezogen. Die aktive Mandanten- oder Gruppenauswahl wird in der jeweiligen Browser-Session gespeichert.
 
+Ab Version `0.10.1` ignoriert die automatische Mandantenermittlung
+mehrwertige Reverse-Relationen. Das behebt unter NetBox 4.6.8 insbesondere den
+Fehler `'RelatedManager' object has no attribute '_meta'` beim Öffnen der
+Seite zum Anlegen einer VLAN-Gruppe.
+
+Ab Version `0.10.2` befindet sich die VLAN-Auswahl beim Anlegen und Bearbeiten
+eines Kabels direkt im Abschnitt **B-Seite**, unterhalb des B-seitigen
+Verbindungsendes.
+
+Ab Version `0.10.3` kann dort optional eine VLAN-Gruppe ausgewählt werden. Sie
+dient als dynamischer Filter für die VLAN-Mehrfachauswahl und wird nicht als
+zusätzliche Eigenschaft der Verbindung gespeichert.
+
 ## Kompatibilität
 
 - NetBox `>=4.6.5,<4.7`
 - Python `>=3.12`
 - optional: NetBox Reorder Rack `1.1.4`
+- optional: NetBox-Export `0.3.11`
+- optional: [MrBlake NetBox Topology Views](https://git.mrblake.cc/MrBlake/mrb-netbox-topology-views) mit Rack-Ansicht
 
 Andere NetBox-Versionen werden vom Plugin absichtlich abgelehnt, da die Anpassung der Core-Navigation von deren HTML-Struktur abhängt.
 
@@ -31,11 +50,12 @@ Das Plugin kann direkt aus dem `main`-Branch installiert werden:
 ```
 
 Für eine reproduzierbare Produktivinstallation sollte statt `main` ein
-Release-Tag oder ein bestimmter Commit verwendet werden:
+bereits veröffentlichter Release-Tag oder eine bestimmte Commit-ID verwendet
+werden. `COMMIT-ID` wird dabei durch den gewünschten Stand ersetzt:
 
 ```bash
 /opt/netbox/venv/bin/pip install --upgrade --force-reinstall \
-  "git+https://git.mrblake.cc/MrBlake/Netbox-Utilities.git@v0.7.2"
+  "git+https://git.mrblake.cc/MrBlake/Netbox-Utilities.git@COMMIT-ID"
 ```
 
 Alternativ kann hinter dem `@` die vollständige Commit-ID stehen.
@@ -67,7 +87,9 @@ PLUGINS = [
 PLUGINS_CONFIG = {
     "netbox_utilities": {
         "navigation_customization_enabled": True,
+        "connection_vlans_enabled": True,
         "reorder_rack_bulk_save_enabled": True,
+        "topology_views_rack_width_enabled": True,
         "tenant_filter_enabled": True,
         "tenant_required": True,
     },
@@ -100,6 +122,88 @@ sudo systemctl restart netbox netbox-rq
 Nach Änderungen an JavaScript oder CSS kann ein Hard-Reload des Browsers mit
 `Strg+F5` erforderlich sein.
 
+Ab Version `0.9.3` werden Rack-SVG und Reorder direkt aus allen Geräten des
+Racks aufgebaut. Dadurch können mehrere Geräte derselben HE nicht mehr durch
+NetBox' native Ein-Gerät-pro-HE-Darstellung verloren gehen. Die Adapter werden
+auch dann eingebunden, wenn keine Teilbreitengeräte gefunden wurden. Nach
+diesem Update ist `collectstatic` deshalb zwingend erforderlich;
+die Dateien `topology-rack-width.js` und `reorder-rack-width.js` müssen unter
+`/opt/netbox/netbox/static/netbox_utilities/` vorhanden sein.
+
+Reorder ersetzt seine nativen Gerätekacheln erst, nachdem ein vollständiger
+und zur JavaScript-Version passender Datensatz geprüft wurde. Bei einer
+gemischten Installation aus altem Python-Code und neuen statischen Dateien
+bleibt deshalb die native Ansicht erhalten, statt ein leeres Rack zu zeigen.
+Ab Version `0.9.4` werden vorhandene Reorder-Kacheln außerdem direkt auf das
+12-Spalten-Raster erweitert und nicht mehr vorsorglich neu erzeugt. Nur ein
+zweites, von NetBox' Ein-Gerät-pro-HE-Darstellung unterschlagenes Gerät wird
+aus den Plugin-Daten ergänzt. Das verhindert browserabhängige leere Racks.
+Ab Version `0.9.5` rendert das Plugin das vollständige 12-Spalten-Rack bereits
+serverseitig in die Reorder-Seite. Die sichtbaren Geräte sind dadurch nicht
+mehr vom Ladezeitpunkt des Browseradapters abhängig. Für die optionale
+Topology-Rack-Ansicht wird die Teilbreitengeometrie zusätzlich als
+serverseitiges CSS ausgegeben; JavaScript wird dort nur noch für Exporte und
+ergänzende Metadaten benötigt.
+Ab Version `0.9.6` verwendet Reorder direkt den bereits durch seinen View
+autorisierten Rack-Datensatz. Die Topology-Rack-Ansicht leitet ihre Breiten
+ausschließlich aus den Geräten ab, die der Topology-View tatsächlich in seine
+HTML-Antwort geschrieben hat. Zusätzliche Berechtigungsabfragen können die
+beiden Ansichten dadurch nicht mehr fälschlich leeren.
+Ab Version `0.9.7` enthält Reorder eigene 12-Spalten-CSS-Regeln. Diese beheben
+die Inkompatibilität zwischen GridStack 10 aus Reorder Rack `1.1.4` und dem
+GridStack-11-Stylesheet von NetBox 4.6.7, durch die Gerätekacheln mit einer
+berechneten Breite von `0px` unsichtbar waren. Topology-Breiten werden außerdem
+nach dem vollständigen Rendern zentral auf die HTTP-Antwort angewendet und
+zusätzlich direkt in die vorhandenen Geräte-Styles geschrieben.
+Ab Version `0.9.8` behalten Geräte beim Ziehen in Reorder ihre tatsächliche
+Rackbreite. Die 12-Spalten-Regeln lassen dazu GridStacks temporären
+Pixelkoordinaten während des Ziehens Vorrang, statt eine Prozentbreite auf das
+Browserfenster anzuwenden. Die serverseitig aufgebauten Reorder-Kacheln zeigen
+außerdem wieder die Front- und Rückseitenbilder des Gerätetyps entsprechend
+der gewählten Ansicht an.
+Bereits vorhandene Geräte, die dieselbe HE und Rackseite belegen, aber noch
+keine Plugin-Platzierungszeile besitzen, werden in Rack-SVG, Reorder und der
+Topology-Rack-Ansicht ohne Datenbankänderung gleichmäßig nebeneinander
+dargestellt. Explizit gespeicherte Rackbreiten und Breitenpositionen haben
+stets Vorrang vor dieser Anzeige-Ableitung.
+
+Die Installation lässt sich anschließend mit diesen Befehlen kontrollieren:
+
+```bash
+/opt/netbox/venv/bin/python -c \
+  "import netbox_utilities; print(netbox_utilities.__version__, netbox_utilities.__file__)"
+
+test -f /opt/netbox/netbox/static/netbox_utilities/reorder-rack-width.js
+test -f /opt/netbox/netbox/static/netbox_utilities/topology-rack-width.js
+grep -q "schema_version !== 3" \
+  /opt/netbox/netbox/static/netbox_utilities/reorder-rack-width.js
+
+cd /opt/netbox/netbox
+/opt/netbox/venv/bin/python manage.py shell -c \
+  "from django.urls import reverse; print(reverse('dcim:rack_reorder', kwargs={'pk': 1})); print(reverse('plugins:netbox_topology_views:rack_elevation'))"
+```
+
+Die letzten beiden Routen müssen auflösbar sein. Die Topology-Rack-Route ist
+im getesteten MrBlake-Develop-Stand `86a8daf45ef380d57ac73b461dbc47a16bb831ba`
+enthalten, aber nicht im gleich bezeichneten öffentlichen Tag `v4.5.1`.
+
+Für Rack `2` kann zusätzlich geprüft werden, welche gespeicherten Breiten das
+Plugin findet. Zwei Geräte derselben HE dürfen dabei unterschiedliche oder
+noch leere Plugin-Werte besitzen; leere Werte werden ab `0.9.3` für die
+Darstellung abgeleitet:
+
+```bash
+cd /opt/netbox/netbox
+/opt/netbox/venv/bin/python manage.py shell -c "
+from dcim.models import Device
+print(list(Device.objects.filter(rack_id=2).order_by('position', 'id').values(
+    'id', 'name', 'position', 'face',
+    'netbox_utilities_rack_placement__width',
+    'netbox_utilities_rack_placement__horizontal_position',
+)))
+"
+```
+
 ## Aktualisierung
 
 Bei einer Installation aus dem `main`-Branch wird das Paket erneut aus Gitea
@@ -132,6 +236,145 @@ empfohlen.
 
 ## Verwendung
 
+### VLANs direkt an Verbindungen dokumentieren
+
+Ab Version `0.10.0` erscheint beim normalen **Anlegen und Bearbeiten** einer
+Kabelverbindung oder Funkverbindung das optionale Feld **VLANs der
+Verbindung**. Darin können ein oder mehrere bestehende NetBox-VLANs ausgewählt
+werden. Die Auswahl wird außerdem auf der Detailseite der Verbindung
+angezeigt.
+
+Die Zuordnung dokumentiert, welche VLANs über die jeweilige Verbindung
+transportiert werden. Sie verändert bewusst nicht automatisch die nativen
+Felder **Untagged VLAN** und **Tagged VLANs** der beteiligten Interfaces, da
+beide Enden unterschiedliche Interface-Modi besitzen können. Diese bleiben
+weiterhin die technische Konfiguration der einzelnen Interfaces.
+
+Die Funktion gilt für:
+
+- physische NetBox-Kabel, einschließlich Verbindungen über Patchfelder;
+- NetBox-Funkverbindungen (`WirelessLink`).
+
+Leere Auswahlen erzeugen keinen Zuordnungsdatensatz. Beim Löschen einer
+Verbindung wird ihre VLAN-Zuordnung automatisch mit entfernt. Das Feature kann
+installationsweit mit `connection_vlans_enabled = False` in `PLUGINS_CONFIG`
+deaktiviert werden.
+
+Ist das optionale NetBox-Export-Plugin installiert, werden diese
+VLAN-Zuordnungen als normale Plugin-Datensätze zusammen mit den Verbindungen
+und VLANs exportiert und wieder importiert.
+
+### Mehrere Geräte nebeneinander in derselben HE
+
+Auf der normalen Seite zum **Anlegen oder Bearbeiten eines Geräts** stehen
+direkt nach **Position** zwei neue optionale Felder zur Verfügung. Dafür wird
+kein separates Plugin-Menü benötigt:
+
+- **Rackbreite**: volle, halbe, Drittel- oder Viertelbreite;
+- **Breitenposition**: Position 1 bis 4, von links gezählt.
+
+Für eine Fritzbox und ein zweites Gerät in derselben HE wird bei beiden
+Geräten beispielsweise **1/2 Rackbreite** gewählt. Die Fritzbox erhält
+**Position 1 (links)**, das andere Gerät **Position 2**. Rack, HE und Rackseite
+dürfen anschließend identisch sein. Die Kollisionsprüfung berücksichtigt
+sowohl die Gerätehöhe als auch die Breite und verhindert horizontale oder
+vertikale Überschneidungen. Mehrere HE hohe Geräte werden ebenfalls
+unterstützt.
+
+Nach einer Änderung der Rackbreite wird die **Breitenposition** unmittelbar
+aktualisiert; ein Zwischenspeichern oder Neuladen ist nicht erforderlich.
+
+Ohne Breitenangabe belegt ein Gerät wie bisher die volle Rackbreite. Ausnahme
+ist eine bereits vorhandene gemeinsame Belegung derselben HE und Rackseite:
+Fehlen dort Plugin-Platzierungen, teilt die Darstellung den verfügbaren Platz
+gleichmäßig auf die zwei bis vier vorhandenen Geräte auf. Diese Ableitung
+ändert keine Datenbankwerte und dient nur dazu, bereits gemeinsam eingepflegte
+Geräte wieder sichtbar zu machen. Es findet keine Migration bestehender
+Platzierungen statt. Explizit gewählte Teilbreite und Position werden auf der
+Geräteseite angezeigt und in der Rackgrafik nebeneinander dargestellt.
+
+NetBox besitzt standardmäßig eine Datenbank-Eindeutigkeit für Rack, HE und
+Rackseite. Die Plugin-Migration `0007` entfernt ausschließlich diese
+Core-Eindeutigkeit, damit mehrere Geräte dieselbe HE verwenden können. Das
+Plugin übernimmt dafür die breitenabhängige Prüfung beim Speichern. Vor einem
+späteren Entfernen des Plugins müssen geteilte Höheneinheiten wieder aufgelöst
+werden; die Core-Eindeutigkeit wird bei einer Deinstallation nicht automatisch
+wiederhergestellt.
+
+Die Zusatzfelder werden im NetBox-Webformular gepflegt. REST- oder normale
+NetBox-CSV-Vorgänge ohne diese Felder behandeln neue Geräte als volle
+Rackbreite. Der nachfolgend beschriebene portable ZIP-Export überträgt sie
+dagegen ausdrücklich.
+
+### Rackbreiten in NetBox-Export
+
+Ist das optionale Plugin
+[NetBox-Export](https://git.mrblake.cc/MrBlake/netbox-export) in Version
+`0.3.11` installiert, erweitert NetBox Utilities dessen ZIP-Export und Import
+automatisch. Für jedes Gerät werden auch die Rackbreite und die von links
+gezählte Breitenposition im Archiv gespeichert. Beim Import berücksichtigt die
+Konfliktprüfung sowohl die Gerätehöhe als auch die horizontale Rackfläche.
+Dadurch können beispielsweise zwei Geräte mit halber Breite wieder in dieselbe
+HE importiert werden, ohne dass das zuerst importierte Gerät aus dem Rack
+entfernt wird.
+
+Auch volle Rackbreite wird ausdrücklich gespeichert. Wird ein früher
+teilbreites Zielgerät durch einen neueren Export auf volle Breite zurückgesetzt,
+entfernt der Import deshalb seine veraltete Teilbreitenzuordnung. Ältere
+Archive ohne diese Zusatzmetadaten bleiben importierbar; vorhandene
+`DeviceRackPlacement`-Datensätze darin werden weiterhin berücksichtigt.
+
+Ab Version `0.9.10` sperrt der Import Geräte und ihre optionalen
+Rackbreitenzuordnungen in getrennten Datenbankabfragen. Damit funktioniert der
+Test- und Echtimport auch unter PostgreSQL, ohne einen unzulässigen
+`FOR UPDATE`-Outer-Join zu erzeugen. Bereits mit Version `0.9.9` erstellte
+Archive müssen dafür nicht neu exportiert werden.
+
+Ab Version `0.9.11` werden alle im Archiv enthaltenen Rackbreiten vor der
+eigentlichen Geräteplatzierung innerhalb derselben Transaktion vorgemerkt.
+Dadurch erkennt die Konfliktprüfung mehrere teilbreite Geräte derselben HE
+bereits während des Imports korrekt und löst kein zuvor platziertes Gerät aus
+dem Rack. Nach der Platzierung werden die Breiten mit dem endgültigen
+Importergebnis abgeglichen.
+
+### Teilbreiten in MrBlake NetBox Topology Views
+
+Ist
+[MrBlake NetBox Topology Views](https://git.mrblake.cc/MrBlake/mrb-netbox-topology-views)
+mit seiner **Rack-Ansicht** installiert, erkennt NetBox Utilities das Plugin
+automatisch. Teilbreitengeräte werden dort anhand ihrer Rackbreite und
+Breitenposition nebeneinander dargestellt. Die aktuelle Rack-Ansicht wird auch
+bei ihren Exporten nach **SVG**, **PNG** und **draw.io** unterstützt. Die
+Kabeltopologie bleibt unverändert, da sie Geräte als frei verschiebbare Knoten
+und nicht als physische Rackflächen darstellt.
+
+Das Topology-Plugin bleibt eine optionale Abhängigkeit. Eine reproduzierbare
+Installation des derzeit getesteten MrBlake-Stands erfolgt über dessen
+Commit-ID:
+
+```bash
+/opt/netbox/venv/bin/pip install --upgrade --force-reinstall \
+  "git+https://git.mrblake.cc/MrBlake/mrb-netbox-topology-views.git@86a8daf45ef380d57ac73b461dbc47a16bb831ba"
+```
+
+Für automatische NetBox-Updates wird derselbe Git-Eintrag zusätzlich in
+`/opt/netbox/local_requirements.txt` aufgenommen. Anschließend müssen beide
+Plugins aktiviert sein; ihre Reihenfolge ist beliebig:
+
+```python
+PLUGINS = [
+    "netbox_topology_views",
+    "netbox_utilities",
+]
+```
+
+Die Integration ändert keine Dateien von Topology Views und erzeugt keine
+zusätzlichen Datenbankeinträge. Sie wird ausschließlich auf dessen Rack-Seite
+geladen und kann mit
+`topology_views_rack_width_enabled = False` in `PLUGINS_CONFIG` deaktiviert
+werden. Ist Topology Views nicht installiert oder enthält der installierte
+Stand keine Rack-Ansicht, bleibt NetBox Utilities unverändert nutzbar.
+
 ### Front- und Rearports von Patchpaneln automatisch verknüpfen
 
 Geräte, deren NetBox-Geräterolle `Patchpanel` heißt, werden automatisch als
@@ -142,25 +385,15 @@ weiter. Auch Kurzformen wie `F01` und `R1` werden als dieselbe Kennung erkannt.
 Fehlt die passende Gegenseite, bleibt der Port unverknüpft; die nachfolgenden
 Nummern rutschen nicht auf.
 
-Die Zuordnung wird nach Änderungen am Gerät, nach dem Einbau eines Moduls und
-nach dem Anlegen oder Umbenennen einzelner Front- beziehungsweise Rearports
-erneut hergestellt. Dabei ersetzt die Patchpanel-Automatik abweichende
-vorhandene Port-Mappings auf diesen Geräten durch die feste 1:1-Zuordnung.
+Die Zuordnung wird ausschließlich beim erstmaligen Anlegen eines Patchpanels,
+beim Einbau eines neuen Moduls sowie beim Anlegen eines neuen Front- oder
+Rearports hergestellt. Das Bearbeiten eines vorhandenen Patchpanels, Moduls
+oder Ports löst die Automatik nicht aus.
 
-Beim Update auf Version `0.7.2` korrigiert eine Plugin-Migration die Zuordnung
-automatisch für alle bereits vorhandenen Geräte mit dieser Rolle und berechnet
-die betroffenen Kabelpfade beziehungsweise Verbindungsenden neu. Vor dem
-Produktivupdate sollte daher geprüft werden, ob Geräte mit bewusst
-abweichenden oder mehrpoligen Mappings nicht die Rolle `Patchpanel` tragen
-sollen.
-
-Der Reparaturlauf kann bei Bedarf jederzeit erneut und ohne erneute Migration
-gestartet werden:
-
-```bash
-cd /opt/netbox/netbox
-/opt/netbox/venv/bin/python manage.py repair_patchpanel_mappings
-```
+Bei Installation oder Update findet kein automatischer Bestandslauf statt.
+Vorhandene Patchpanel-Geräte und deren Kabelpfade bleiben unverändert. Die
+Automatik greift erst, wenn ein betreffendes Gerät, Modul oder ein Front-/Rearport
+neu angelegt wird.
 
 ### Mehrere Geräte mit NetBox Reorder Rack verschieben
 
@@ -168,6 +401,13 @@ Wenn `netbox-reorder-rack` in Version `1.1.4` installiert und aktiviert ist,
 erweitert NetBox Utilities dessen vorhandenen Speichervorgang automatisch.
 In der Drag-and-drop-Ansicht können mehrere Geräte verschoben oder miteinander
 getauscht und anschließend gemeinsam über **Save** gespeichert werden.
+Teilbreitengeräte werden dort ebenfalls nebeneinander angezeigt. Das
+12-spaltige Raster bildet volle, halbe, Drittel- und Viertelbreite exakt ab.
+Beim horizontalen Verschieben rastet ein Gerät auf einer für seine Breite
+gültigen Position ein; **Save** speichert Höhe, Rackseite und Breitenposition
+gemeinsam in derselben Transaktion. Die gewählte Rackbreite selbst wird in der
+Reorder-Ansicht nicht verändert und weiterhin auf der Geräte-Neu- oder
+Bearbeitungsseite gepflegt.
 
 Die optionale Abhängigkeit wird separat installiert und für spätere NetBox-
 Updates in `/opt/netbox/local_requirements.txt` aufgenommen:
@@ -187,8 +427,8 @@ PLUGINS = [
 ```
 
 NetBox Utilities verändert keine Dateien des Reorder-Plugins. Stattdessen wird
-dessen API beim Start kompatibel erweitert. Beim Speichern werden alle
-betroffenen Geräte und das Rack gesperrt, die alten Positionen gemeinsam
+dessen Oberfläche und API beim Start kompatibel erweitert. Beim Speichern
+werden alle betroffenen Geräte und das Rack gesperrt, die alten Positionen gemeinsam
 freigegeben und danach sämtliche Zielpositionen mit der normalen
 NetBox-Modellvalidierung geprüft. Der Vorgang läuft in einer Transaktion: Bei
 einem Platz-, Validierungs- oder Berechtigungsfehler bleibt das gesamte Rack
@@ -201,7 +441,7 @@ Andere Versionen als `1.1.4` werden aus Sicherheitsgründen nicht automatisch
 verändert und erzeugen lediglich einen Hinweis im NetBox-Log. Das
 Reorder-Projekt selbst weist derzeit offiziell nur Kompatibilität bis NetBox
 4.5 aus; die Erweiterung in diesem Plugin ist gezielt für die hier unterstützte
-NetBox-Version 4.6.5 umgesetzt.
+NetBox-Versionen 4.6.5 bis 4.6.7 umgesetzt und getestet.
 
 ### Mehrere Bilder hochladen
 

netbox_utilities/__init__.py

@@ -1,12 +1,12 @@
 from netbox.plugins import PluginConfig, get_plugin_config
 
-__version__ = "0.7.2"
+__version__ = "0.10.3"
 
 
 class NetBoxUtilitiesConfig(PluginConfig):
     name = "netbox_utilities"
     verbose_name = "NetBox Utilities"
-    description = "Navigation, tenant utilities, patchpanel mapping, bulk uploads, and atomic rack reordering"
+    description = "Navigation, tenant utilities, connection VLANs, partial-width racks, and bulk operations"
     version = __version__
     author = "LKE"
     base_url = "utilities"
@@ -14,7 +14,9 @@ class NetBoxUtilitiesConfig(PluginConfig):
     max_version = "4.6.99"
     default_settings = {
         "navigation_customization_enabled": True,
+        "connection_vlans_enabled": True,
         "reorder_rack_bulk_save_enabled": True,
+        "topology_views_rack_width_enabled": True,
         "tenant_filter_enabled": True,
         "tenant_required": True,
     }
@@ -25,12 +27,22 @@ class NetBoxUtilitiesConfig(PluginConfig):
     def ready(self):
         super().ready()
         from .patchpanel import install_patchpanel_automation
+        from .rack_width import install_rack_width_support
         from .tenant_scope import install_search_filter
         from .tenant_validation import install_tenant_validation
 
         install_search_filter()
         install_tenant_validation()
         install_patchpanel_automation()
+        install_rack_width_support()
+        if get_plugin_config("netbox_utilities", "connection_vlans_enabled"):
+            from .connection_vlans import install_connection_vlan_support
+
+            install_connection_vlan_support()
+        if self.apps.is_installed("netbox_export"):
+            from .netbox_export import install_netbox_export_rack_width_support
+
+            install_netbox_export_rack_width_support()
         if get_plugin_config("netbox_utilities", "reorder_rack_bulk_save_enabled"):
             from .reorder_rack import install_reorder_rack_bulk_save
 

netbox_utilities/connection_vlans.py

@@ -0,0 +1,150 @@
+from copy import deepcopy
+from functools import wraps
+
+from ipam.models import VLAN, VLANGroup
+from utilities.forms.fields import DynamicModelChoiceField, DynamicModelMultipleChoiceField
+from utilities.forms.rendering import FieldSet
+
+from .models import CableVLANAssignment, WirelessLinkVLANAssignment
+
+FORM_FIELD = "utilities_vlans"
+GROUP_FILTER_FIELD = "utilities_vlan_group"
+PATCH_MARKER = "_netbox_utilities_connection_vlans_installed"
+
+
+def include_connection_vlans_in_fieldsets(fieldsets):
+    """Add the connection VLAN field to an isolated copy of a form layout."""
+    if not fieldsets:
+        return (FieldSet(GROUP_FILTER_FIELD, FORM_FIELD, name="VLANs der Verbindung"),)
+
+    copied_fieldsets = deepcopy(fieldsets)
+
+    def insert_into_link_group(group):
+        items = list(getattr(group, "items", ()))
+        if "description" in items or "tags" in items:
+            items = [item for item in items if item not in (GROUP_FILTER_FIELD, FORM_FIELD)]
+            index = items.index("tags") if "tags" in items else len(items)
+            items[index:index] = (GROUP_FILTER_FIELD, FORM_FIELD)
+            group.items = tuple(items)
+            return True
+
+        for item in items:
+            if any(insert_into_link_group(nested) for nested in getattr(item, "groups", ())):
+                return True
+        return False
+
+    if any(insert_into_link_group(fieldset) for fieldset in copied_fieldsets):
+        return tuple(copied_fieldsets)
+    return (*copied_fieldsets, FieldSet(GROUP_FILTER_FIELD, FORM_FIELD, name="VLANs der Verbindung"))
+
+
+def _build_connection_vlan_form(base_form, assignment_model, target_field):
+    if getattr(base_form, PATCH_MARKER, False):
+        return base_form
+
+    class ConnectionVLANForm(base_form):
+        utilities_vlan_group = DynamicModelChoiceField(
+            queryset=VLANGroup.objects.all(),
+            required=False,
+            selector=True,
+            label="VLAN-Gruppe (Filter)",
+            help_text="Optional: Schränkt die nachfolgende VLAN-Auswahl auf diese Gruppe ein.",
+        )
+        utilities_vlans = DynamicModelMultipleChoiceField(
+            queryset=VLAN.objects.all(),
+            required=False,
+            selector=True,
+            query_params={"group_id": f"${GROUP_FILTER_FIELD}"},
+            label="VLANs der Verbindung",
+            help_text=(
+                "Dokumentiert ein oder mehrere VLANs auf dieser Verbindung. "
+                "Die Tagged-/Untagged-VLAN-Einstellungen der Interfaces bleiben unverändert."
+            ),
+        )
+
+        @property
+        def fieldsets(self):
+            return include_connection_vlans_in_fieldsets(super().fieldsets)
+
+        def __init__(self, *args, **kwargs):
+            super().__init__(*args, **kwargs)
+            if not self.is_bound and getattr(self.instance, "pk", None):
+                assignment = (
+                    assignment_model.objects.filter(**{target_field: self.instance}).prefetch_related("vlans").first()
+                )
+                if assignment is not None:
+                    selected_vlans = list(assignment.vlans.all())
+                    self.initial[FORM_FIELD] = selected_vlans
+                    group_ids = {vlan.group_id for vlan in selected_vlans if getattr(vlan, "group_id", None)}
+                    if len(group_ids) == 1:
+                        self.initial[GROUP_FILTER_FIELD] = group_ids.pop()
+
+        def save(self, commit=True):
+            connection = super().save(commit=commit)
+            if commit:
+                self._save_connection_vlans(connection)
+            else:
+                native_save_m2m = self.save_m2m
+
+                def save_m2m():
+                    native_save_m2m()
+                    self._save_connection_vlans(connection)
+
+                self.save_m2m = save_m2m
+            return connection
+
+        def _save_connection_vlans(self, connection):
+            selected_vlans = list(self.cleaned_data.get(FORM_FIELD) or ())
+            lookup = {target_field: connection}
+            if not selected_vlans:
+                assignment_model.objects.filter(**lookup).delete()
+                return
+            assignment, _created = assignment_model.objects.get_or_create(**lookup)
+            assignment.vlans.set(selected_vlans)
+
+    ConnectionVLANForm.__name__ = f"ConnectionVLAN{base_form.__name__}"
+    ConnectionVLANForm.__qualname__ = ConnectionVLANForm.__name__
+    ConnectionVLANForm.__module__ = __name__
+    setattr(ConnectionVLANForm, PATCH_MARKER, True)
+    return ConnectionVLANForm
+
+
+def _install_cable_vlan_form():
+    import dcim.forms
+    from dcim.forms import connections
+    from dcim.views import CableEditView
+
+    if getattr(CableEditView, PATCH_MARKER, False):
+        return
+
+    native_get_cable_form = dcim.forms.get_cable_form
+
+    @wraps(native_get_cable_form)
+    def get_connection_vlan_cable_form(*args, **kwargs):
+        base_form = native_get_cable_form(*args, **kwargs)
+        return _build_connection_vlan_form(base_form, CableVLANAssignment, "cable")
+
+    setattr(get_connection_vlan_cable_form, PATCH_MARKER, True)
+    dcim.forms.get_cable_form = get_connection_vlan_cable_form
+    connections.get_cable_form = get_connection_vlan_cable_form
+    CableEditView.template_name = "netbox_utilities/cable_edit.html"
+    CableEditView.htmx_template_name = "netbox_utilities/cable_edit_form.html"
+    setattr(CableEditView, PATCH_MARKER, True)
+
+
+def _install_wireless_link_vlan_form():
+    from wireless.views import WirelessLinkEditView
+
+    if getattr(WirelessLinkEditView, PATCH_MARKER, False):
+        return
+    WirelessLinkEditView.form = _build_connection_vlan_form(
+        WirelessLinkEditView.form,
+        WirelessLinkVLANAssignment,
+        "wireless_link",
+    )
+    setattr(WirelessLinkEditView, PATCH_MARKER, True)
+
+
+def install_connection_vlan_support():
+    _install_cable_vlan_form()
+    _install_wireless_link_vlan_form()

netbox_utilities/management/commands/repair_patchpanel_mappings.py

@@ -1,15 +0,0 @@
-from django.core.management.base import BaseCommand
-
-from netbox_utilities.patchpanel import repair_existing_patchpanels
-
-
-class Command(BaseCommand):
-    help = "Repair front/rear mappings and cable paths for all devices with the Patchpanel role"
-
-    def handle(self, *args, **options):
-        device_count, mapping_count = repair_existing_patchpanels()
-        self.stdout.write(
-            self.style.SUCCESS(
-                f"Repaired {mapping_count} front/rear mappings on {device_count} Patchpanel devices."
-            )
-        )

netbox_utilities/middleware.py

@@ -22,7 +22,10 @@ class GlobalTenantFilterMiddleware:
         try:
             if scope is not None and request.method in {"GET", "HEAD"}:
                 self._inject_filter_parameter(request, scope)
-            return self.get_response(request)
+            response = self.get_response(request)
+            from .topology_views import apply_topology_rack_widths
+
+            return apply_topology_rack_widths(request, response)
         finally:
             active_tenant_scope.reset(token)
 

netbox_utilities/migrations/0004_patchpanel_port_mappings.py

@@ -1,55 +1,12 @@
-import re
-
 from django.db import migrations
 
 
-def natural_port_key(port):
-    parts = tuple(
-        int(part) if part.isdigit() else part.casefold()
-        for part in re.split(r"(\d+)", str(port.name))
-    )
-    return parts, port.pk
-
-
-def synchronize_existing_patchpanels(apps, schema_editor):
-    Device = apps.get_model("dcim", "Device")
-    FrontPort = apps.get_model("dcim", "FrontPort")
-    PortMapping = apps.get_model("dcim", "PortMapping")
-    RearPort = apps.get_model("dcim", "RearPort")
-    database = schema_editor.connection.alias
-
-    device_ids = Device.objects.using(database).filter(role__name__iexact="Patchpanel").values_list("pk", flat=True)
-    for device_id in device_ids.iterator():
-        front_ports = sorted(
-            FrontPort.objects.using(database).filter(device_id=device_id).only("pk", "name"),
-            key=natural_port_key,
-        )
-        rear_ports = sorted(
-            RearPort.objects.using(database).filter(device_id=device_id).only("pk", "name"),
-            key=natural_port_key,
-        )
-        PortMapping.objects.using(database).filter(device_id=device_id).delete()
-        PortMapping.objects.using(database).bulk_create(
-            [
-                PortMapping(
-                    device_id=device_id,
-                    front_port_id=front_port.pk,
-                    rear_port_id=rear_port.pk,
-                    front_port_position=1,
-                    rear_port_position=1,
-                )
-                for front_port, rear_port in zip(front_ports, rear_ports)
-            ],
-            batch_size=1000,
-        )
-
-
 class Migration(migrations.Migration):
     dependencies = [
         ("dcim", "0237_module_remove_local_context_data"),
         ("netbox_utilities", "0003_navigationpreference_sidebar_layout"),
     ]
 
-    operations = [
-        migrations.RunPython(synchronize_existing_patchpanels, migrations.RunPython.noop),
-    ]
+    # Kept in the migration graph for installations which already recorded it.
+    # Existing devices must not be modified automatically.
+    operations = []

netbox_utilities/migrations/0005_fix_patchpanel_port_number_mappings.py

@@ -1,81 +1,11 @@
-import re
-from collections import defaultdict
-
 from django.db import migrations
 
 
-def natural_port_key(port):
-    parts = tuple(
-        int(part) if part.isdigit() else part.casefold()
-        for part in re.split(r"(\d+)", str(port.name))
-    )
-    return parts, port.pk
-
-
-def port_identifier(port):
-    name = str(port.name).casefold()
-    name = re.sub(r"\b(?:front|rear)(?:[\s_-]*port)?(?=\b|\d)", " ", name)
-    name = re.sub(r"^(?:fp|rp|f|r)(?=\s*[-_.:/]?\s*\d)", "", name)
-    tokens = re.findall(r"\d+|[^\W\d_]+", name)
-    identifier = tuple(int(token) if token.isdigit() else token for token in tokens)
-    return identifier or None
-
-
-def pair_ports(front_ports, rear_ports):
-    front_by_identifier = defaultdict(list)
-    rear_by_identifier = defaultdict(list)
-    for port in front_ports:
-        if identifier := port_identifier(port):
-            front_by_identifier[identifier].append(port)
-    for port in rear_ports:
-        if identifier := port_identifier(port):
-            rear_by_identifier[identifier].append(port)
-
-    pairs = []
-    for identifier, matching_front_ports in front_by_identifier.items():
-        pairs.extend(
-            zip(
-                sorted(matching_front_ports, key=natural_port_key),
-                sorted(rear_by_identifier.get(identifier, []), key=natural_port_key),
-            )
-        )
-    return pairs
-
-
-def fix_existing_patchpanel_mappings(apps, schema_editor):
-    Device = apps.get_model("dcim", "Device")
-    FrontPort = apps.get_model("dcim", "FrontPort")
-    PortMapping = apps.get_model("dcim", "PortMapping")
-    RearPort = apps.get_model("dcim", "RearPort")
-    database = schema_editor.connection.alias
-
-    device_ids = Device.objects.using(database).filter(role__name__iexact="Patchpanel").values_list("pk", flat=True)
-    for device_id in device_ids.iterator():
-        front_ports = FrontPort.objects.using(database).filter(device_id=device_id).only("pk", "name")
-        rear_ports = RearPort.objects.using(database).filter(device_id=device_id).only("pk", "name")
-        pairs = pair_ports(front_ports, rear_ports)
-
-        PortMapping.objects.using(database).filter(device_id=device_id).delete()
-        PortMapping.objects.using(database).bulk_create(
-            [
-                PortMapping(
-                    device_id=device_id,
-                    front_port_id=front_port.pk,
-                    rear_port_id=rear_port.pk,
-                    front_port_position=1,
-                    rear_port_position=1,
-                )
-                for front_port, rear_port in pairs
-            ],
-            batch_size=1000,
-        )
-
-
 class Migration(migrations.Migration):
     dependencies = [
         ("netbox_utilities", "0004_patchpanel_port_mappings"),
     ]
 
-    operations = [
-        migrations.RunPython(fix_existing_patchpanel_mappings, migrations.RunPython.noop),
-    ]
+    # Kept in the migration graph for installations which already recorded it.
+    # Existing devices must not be modified automatically.
+    operations = []

netbox_utilities/migrations/0006_retrace_existing_patchpanel_paths.py

@@ -1,19 +1,11 @@
 from django.db import migrations
 
 
-def repair_mappings_and_paths(apps, schema_editor):
-    # Runtime models are intentional here: NetBox's CablePath.retrace() is
-    # required to refresh the denormalized path data after migration 0005.
-    from netbox_utilities.patchpanel import repair_existing_patchpanels
-
-    repair_existing_patchpanels()
-
-
 class Migration(migrations.Migration):
     dependencies = [
         ("netbox_utilities", "0005_fix_patchpanel_port_number_mappings"),
     ]
 
-    operations = [
-        migrations.RunPython(repair_mappings_and_paths, migrations.RunPython.noop),
-    ]
+    # Kept in the migration graph for installations which already recorded it.
+    # Existing devices and cable paths must not be modified automatically.
+    operations = []

netbox_utilities/migrations/0007_devicerackplacement.py

@@ -0,0 +1,65 @@
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+def drop_core_rack_position_constraint(apps, schema_editor):
+    if schema_editor.connection.vendor == "postgresql":
+        schema_editor.execute(
+            'ALTER TABLE "dcim_device" DROP CONSTRAINT IF EXISTS "dcim_device_unique_rack_position_face"'
+        )
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("dcim", "0237_module_remove_local_context_data"),
+        ("netbox_utilities", "0006_retrace_existing_patchpanel_paths"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="DeviceRackPlacement",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name="ID"),
+                ),
+                (
+                    "width",
+                    models.PositiveSmallIntegerField(
+                        choices=[(2, "1/2 Rackbreite"), (3, "1/3 Rackbreite"), (4, "1/4 Rackbreite")]
+                    ),
+                ),
+                (
+                    "horizontal_position",
+                    models.PositiveSmallIntegerField(
+                        help_text="Position von links innerhalb der Rackbreite.",
+                        validators=[
+                            django.core.validators.MinValueValidator(1),
+                            django.core.validators.MaxValueValidator(4),
+                        ],
+                    ),
+                ),
+                ("updated", models.DateTimeField(auto_now=True)),
+                (
+                    "device",
+                    models.OneToOneField(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="netbox_utilities_rack_placement",
+                        to="dcim.device",
+                    ),
+                ),
+            ],
+            options={
+                "verbose_name": "Gerätebreite im Rack",
+                "verbose_name_plural": "Gerätebreiten im Rack",
+                "constraints": [
+                    models.CheckConstraint(
+                        condition=models.Q(width__gte=models.F("horizontal_position")),
+                        name="netbox_utilities_placement_position_within_width",
+                    )
+                ],
+            },
+        ),
+        migrations.RunPython(drop_core_rack_position_constraint, migrations.RunPython.noop),
+    ]

netbox_utilities/migrations/0008_connection_vlan_assignments.py

@@ -0,0 +1,73 @@
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("ipam", "0001_squashed"),
+        ("netbox_utilities", "0007_devicerackplacement"),
+        ("wireless", "0001_squashed_0008"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="CableVLANAssignment",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name="ID"),
+                ),
+                ("updated", models.DateTimeField(auto_now=True)),
+                (
+                    "cable",
+                    models.OneToOneField(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="netbox_utilities_vlan_assignment",
+                        to="dcim.cable",
+                    ),
+                ),
+                (
+                    "vlans",
+                    models.ManyToManyField(
+                        blank=True,
+                        related_name="netbox_utilities_cable_assignments",
+                        to="ipam.vlan",
+                    ),
+                ),
+            ],
+            options={
+                "verbose_name": "VLAN-Zuordnung einer Kabelverbindung",
+                "verbose_name_plural": "VLAN-Zuordnungen von Kabelverbindungen",
+            },
+        ),
+        migrations.CreateModel(
+            name="WirelessLinkVLANAssignment",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name="ID"),
+                ),
+                ("updated", models.DateTimeField(auto_now=True)),
+                (
+                    "vlans",
+                    models.ManyToManyField(
+                        blank=True,
+                        related_name="netbox_utilities_wireless_link_assignments",
+                        to="ipam.vlan",
+                    ),
+                ),
+                (
+                    "wireless_link",
+                    models.OneToOneField(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="netbox_utilities_vlan_assignment",
+                        to="wireless.wirelesslink",
+                    ),
+                ),
+            ],
+            options={
+                "verbose_name": "VLAN-Zuordnung einer Funkverbindung",
+                "verbose_name_plural": "VLAN-Zuordnungen von Funkverbindungen",
+            },
+        ),
+    ]

netbox_utilities/models.py

@@ -46,3 +46,78 @@ class UtilitiesSettings(models.Model):
 
     def __str__(self):
         return "NetBox Utilities settings"
+
+
+class DeviceRackPlacement(models.Model):
+    WIDTH_CHOICES = (
+        (2, "1/2 Rackbreite"),
+        (3, "1/3 Rackbreite"),
+        (4, "1/4 Rackbreite"),
+    )
+
+    device = models.OneToOneField(
+        "dcim.Device",
+        on_delete=models.CASCADE,
+        related_name="netbox_utilities_rack_placement",
+    )
+    width = models.PositiveSmallIntegerField(choices=WIDTH_CHOICES)
+    horizontal_position = models.PositiveSmallIntegerField(
+        validators=[MinValueValidator(1), MaxValueValidator(4)],
+        help_text="Position von links innerhalb der Rackbreite.",
+    )
+    updated = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        constraints = (
+            models.CheckConstraint(
+                condition=models.Q(width__gte=models.F("horizontal_position")),
+                name="netbox_utilities_placement_position_within_width",
+            ),
+        )
+        verbose_name = "Gerätebreite im Rack"
+        verbose_name_plural = "Gerätebreiten im Rack"
+
+    def __str__(self):
+        return f"{self.device}: 1/{self.width}, Position {self.horizontal_position}"
+
+
+class CableVLANAssignment(models.Model):
+    cable = models.OneToOneField(
+        "dcim.Cable",
+        on_delete=models.CASCADE,
+        related_name="netbox_utilities_vlan_assignment",
+    )
+    vlans = models.ManyToManyField(
+        "ipam.VLAN",
+        related_name="netbox_utilities_cable_assignments",
+        blank=True,
+    )
+    updated = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        verbose_name = "VLAN-Zuordnung einer Kabelverbindung"
+        verbose_name_plural = "VLAN-Zuordnungen von Kabelverbindungen"
+
+    def __str__(self):
+        return f"VLANs für Kabel {self.cable}"
+
+
+class WirelessLinkVLANAssignment(models.Model):
+    wireless_link = models.OneToOneField(
+        "wireless.WirelessLink",
+        on_delete=models.CASCADE,
+        related_name="netbox_utilities_vlan_assignment",
+    )
+    vlans = models.ManyToManyField(
+        "ipam.VLAN",
+        related_name="netbox_utilities_wireless_link_assignments",
+        blank=True,
+    )
+    updated = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        verbose_name = "VLAN-Zuordnung einer Funkverbindung"
+        verbose_name_plural = "VLAN-Zuordnungen von Funkverbindungen"
+
+    def __str__(self):
+        return f"VLANs für Funkverbindung {self.wireless_link}"

netbox_utilities/netbox_export.py

@@ -0,0 +1,226 @@
+import logging
+from dataclasses import dataclass
+from decimal import Decimal
+from functools import wraps
+from importlib import import_module
+
+from django.apps import apps
+from django.core.exceptions import ValidationError
+
+from .models import DeviceRackPlacement
+from .rack_width import (
+    FULL_WIDTH,
+    get_width_position,
+    normalize_width_position,
+    placement_rectangles_overlap,
+    stage_width_position,
+)
+
+logger = logging.getLogger(__name__)
+
+SUPPORTED_NETBOX_EXPORT_VERSIONS = {"0.3.11"}
+RACK_WIDTH_RECORD_KEY = "netbox_utilities_rack_placement"
+PATCH_MARKER = "_netbox_utilities_rack_width_version"
+PATCH_VERSION = 1
+
+
+@dataclass(frozen=True)
+class WidthAwareDeferredDevicePlacement:
+    rack_spec: dict | None
+    position: object
+    face: object
+    width: int
+    horizontal_position: int
+
+
+def _is_device(value):
+    return getattr(getattr(value, "_meta", None), "label_lower", None) == "dcim.device"
+
+
+def _serialize_rack_width(original, obj, *args, **kwargs):
+    record = original(obj, *args, **kwargs)
+    if _is_device(obj):
+        width, horizontal_position = get_width_position(obj)
+        record[RACK_WIDTH_RECORD_KEY] = {
+            "schema_version": 1,
+            "width": width,
+            "horizontal_position": horizontal_position,
+        }
+    return record
+
+
+def _defer_rack_width(original, model, record):
+    prepared, placement = original(model, record)
+    if placement is None:
+        return prepared, placement
+
+    metadata = record.get(RACK_WIDTH_RECORD_KEY)
+    if not isinstance(metadata, dict) or metadata.get("schema_version") != 1:
+        return prepared, placement
+    try:
+        width, horizontal_position = normalize_width_position(
+            metadata.get("width"),
+            metadata.get("horizontal_position"),
+        )
+    except ValidationError:
+        logger.warning("NetBox Export archive contains invalid rack width metadata for %s", record.get("id"))
+        return prepared, placement
+
+    return prepared, WidthAwareDeferredDevicePlacement(
+        rack_spec=placement.rack_spec,
+        position=placement.position,
+        face=placement.face,
+        width=width,
+        horizontal_position=horizontal_position,
+    )
+
+
+def _device_footprint(device):
+    device_type = getattr(device, "device_type", None)
+    height = Decimal(str(getattr(device_type, "u_height", 1) or 0))
+    if height <= 0:
+        height = Decimal("0.5")
+    return height, bool(getattr(device_type, "is_full_depth", False))
+
+
+def _width_aware_device_placement_conflicts(original, device, rack, position, face):
+    if not _is_device(device):
+        return original(device, rack, position, face)
+    if rack is None or position is None:
+        return []
+
+    width, horizontal_position = get_width_position(device)
+    height, full_depth = _device_footprint(device)
+    candidates = list(
+        type(device)
+        ._default_manager.select_for_update()
+        .select_related("device_type")
+        .filter(rack=rack, position__isnull=False)
+        .exclude(pk=device.pk)
+    )
+    stored_placements = {
+        placement.device_id: placement
+        for placement in DeviceRackPlacement.objects.select_for_update().filter(
+            device_id__in=[candidate.pk for candidate in candidates]
+        )
+    }
+    conflicts = []
+    for candidate in candidates:
+        candidate_height, candidate_full_depth = _device_footprint(candidate)
+        if not (full_depth or candidate_full_depth or candidate.face == face):
+            continue
+        stored_placement = stored_placements.get(candidate.pk)
+        if stored_placement is None:
+            candidate_width, candidate_horizontal_position = FULL_WIDTH, 1
+        else:
+            candidate_width, candidate_horizontal_position = normalize_width_position(
+                stored_placement.width,
+                stored_placement.horizontal_position,
+            )
+        if placement_rectangles_overlap(
+            position,
+            height,
+            width,
+            horizontal_position,
+            candidate.position,
+            candidate_height,
+            candidate_width,
+            candidate_horizontal_position,
+        ):
+            conflicts.append(candidate)
+    return conflicts
+
+
+def _apply_rack_widths(original, placements, resolved, resolver, compatibility, **kwargs):
+    placements = list(placements)
+    width_aware = []
+    for record_id, placement in placements:
+        if not isinstance(placement, WidthAwareDeferredDevicePlacement):
+            continue
+        device = resolved[record_id]
+        stage_width_position(device, placement.width, placement.horizontal_position)
+        width_aware.append((device, placement))
+
+    # The native placement pass reloads rack occupants from the database for
+    # every device. Persist all imported widths first so a device placed early
+    # in the same pass is not mistaken for a full-width conflict later on.
+    for device, placement in width_aware:
+        _save_rack_width(device, placement)
+
+    result = original(placements, resolved, resolver, compatibility, **kwargs)
+
+    for device, placement in width_aware:
+        if placement.width == FULL_WIDTH or not device.rack_id or not device.position:
+            DeviceRackPlacement.objects.filter(device=device).delete()
+        else:
+            _save_rack_width(device, placement)
+    return result
+
+
+def _save_rack_width(device, placement):
+    if placement.width == FULL_WIDTH:
+        DeviceRackPlacement.objects.filter(device=device).delete()
+        return
+    DeviceRackPlacement.objects.update_or_create(
+        device=device,
+        defaults={
+            "width": placement.width,
+            "horizontal_position": placement.horizontal_position,
+        },
+    )
+
+
+def _rack_placement_is_exportable(original, model):
+    if model is DeviceRackPlacement:
+        return True
+    return original(model)
+
+
+def _patch_function(module, name, wrapper_factory):
+    current = getattr(module, name)
+    if getattr(current, PATCH_MARKER, None) == PATCH_VERSION:
+        return
+    original = current
+
+    @wraps(original)
+    def patched(*args, **kwargs):
+        return wrapper_factory(original, *args, **kwargs)
+
+    setattr(patched, PATCH_MARKER, PATCH_VERSION)
+    setattr(module, name, patched)
+
+
+def install_netbox_export_rack_width_support():
+    if not apps.is_installed("netbox_export"):
+        return False
+
+    plugin_config = apps.get_app_config("netbox_export")
+    plugin_version = getattr(plugin_config, "version", None)
+    if plugin_version not in SUPPORTED_NETBOX_EXPORT_VERSIONS:
+        logger.warning(
+            "NetBox Utilities did not patch netbox-export version %s; supported versions: %s",
+            plugin_version,
+            ", ".join(sorted(SUPPORTED_NETBOX_EXPORT_VERSIONS)),
+        )
+        return False
+
+    exporter = import_module("netbox_export.services.exporter")
+    graph = import_module("netbox_export.services.graph")
+    importer = import_module("netbox_export.services.importer")
+    required = (
+        (exporter, "serialize_object"),
+        (graph, "is_exportable_model"),
+        (importer, "_defer_device_placement"),
+        (importer, "_device_placement_conflicts"),
+        (importer, "_apply_device_placements"),
+    )
+    if not all(hasattr(module, name) for module, name in required):
+        logger.warning("NetBox Utilities could not find the expected netbox-export 0.3.11 integration hooks")
+        return False
+
+    _patch_function(exporter, "serialize_object", _serialize_rack_width)
+    _patch_function(graph, "is_exportable_model", _rack_placement_is_exportable)
+    _patch_function(importer, "_defer_device_placement", _defer_rack_width)
+    _patch_function(importer, "_device_placement_conflicts", _width_aware_device_placement_conflicts)
+    _patch_function(importer, "_apply_device_placements", _apply_rack_widths)
+    return True

netbox_utilities/patchpanel.py

@@ -75,7 +75,7 @@ def retrace_patchpanel_paths(ports):
     return retraced
 
 
-def synchronize_patchpanel(device_id, *, force_retrace=False):
+def synchronize_patchpanel(device_id):
     """Enforce front position 1 -> rear position 1 for a Patchpanel device."""
     if not device_id:
         return 0
@@ -113,28 +113,12 @@ def synchronize_patchpanel(device_id, *, force_retrace=False):
                     for front, rear in pairs
                 ]
             )
-            force_retrace = True
-
-        if force_retrace:
             retrace_patchpanel_paths([*front_ports, *rear_ports])
         return len(pairs)
 
 
-def repair_existing_patchpanels():
-    """Repair mappings and cable paths for all existing Patchpanel devices."""
-    from dcim.models import Device
-
-    device_ids = Device.objects.filter(role__name__iexact=PATCHPANEL_ROLE_NAME).values_list("pk", flat=True)
-    device_count = 0
-    mapping_count = 0
-    for device_id in device_ids:
-        mapping_count += synchronize_patchpanel(device_id, force_retrace=True)
-        device_count += 1
-    return device_count, mapping_count
-
-
-def _component_saved(sender, instance, raw=False, **kwargs):
-    if not raw and not _component_instantiation_active.get():
+def _component_saved(sender, instance, created=False, raw=False, **kwargs):
+    if created and not raw and not _component_instantiation_active.get():
         synchronize_patchpanel(getattr(instance, "device_id", None))
 
 
@@ -147,6 +131,10 @@ def _wrap_component_container_save(model, device_id_getter):
 
     @wraps(original_save)
     def patchpanel_aware_save(instance, *args, **kwargs):
+        created = instance._state.adding
+        if not created:
+            return original_save(instance, *args, **kwargs)
+
         token = _component_instantiation_active.set(True)
         try:
             result = original_save(instance, *args, **kwargs)

netbox_utilities/rack_width.py

@@ -0,0 +1,592 @@
+import decimal
+import logging
+from collections import defaultdict
+from contextvars import ContextVar
+from copy import deepcopy
+from fractions import Fraction
+from functools import wraps
+
+from django import forms
+from django.core.exceptions import ObjectDoesNotExist, ValidationError
+from django.db.models import Count, Q
+from django.db.models.signals import post_save, pre_save
+
+from .models import DeviceRackPlacement
+
+logger = logging.getLogger(__name__)
+
+FULL_WIDTH = 1
+WIDTH_CHOICES = (
+    (FULL_WIDTH, "Volle Rackbreite"),
+    (2, "1/2 Rackbreite"),
+    (3, "1/3 Rackbreite"),
+    (4, "1/4 Rackbreite"),
+)
+POSITION_CHOICES = (
+    (1, "Position 1 (links)"),
+    (2, "Position 2"),
+    (3, "Position 3"),
+    (4, "Position 4 (rechts)"),
+)
+CORE_RACK_POSITION_CONSTRAINT = "dcim_device_unique_rack_position_face"
+
+_validated_device = ContextVar("netbox_utilities_width_validated_device", default=None)
+
+RACK_WIDTH_FORM_FIELDS = ("utilities_rack_width", "utilities_horizontal_position")
+
+
+def normalize_width_position(width, horizontal_position):
+    try:
+        width = int(width or FULL_WIDTH)
+        horizontal_position = int(horizontal_position or 1)
+    except (TypeError, ValueError):
+        raise ValidationError("Rackbreite und Breitenposition sind ungültig.") from None
+    if width not in {1, 2, 3, 4}:
+        raise ValidationError("Die Rackbreite muss voll, 1/2, 1/3 oder 1/4 sein.")
+    if width == FULL_WIDTH:
+        return FULL_WIDTH, 1
+    if not 1 <= horizontal_position <= width:
+        raise ValidationError(f"Für 1/{width} Rackbreite sind nur die Positionen 1 bis {width} möglich.")
+    return width, horizontal_position
+
+
+def horizontal_interval(width, horizontal_position):
+    width, horizontal_position = normalize_width_position(width, horizontal_position)
+    return Fraction(horizontal_position - 1, width), Fraction(horizontal_position, width)
+
+
+def intervals_overlap(first, second):
+    return max(first[0], second[0]) < min(first[1], second[1])
+
+
+def intervals_cover_full_width(intervals):
+    if not intervals:
+        return False
+    merged_end = Fraction(0, 1)
+    for start, end in sorted(intervals):
+        if start > merged_end:
+            return False
+        merged_end = max(merged_end, end)
+    return merged_end >= 1
+
+
+def placement_rectangles_overlap(
+    first_position,
+    first_height,
+    first_width,
+    first_horizontal_position,
+    second_position,
+    second_height,
+    second_width,
+    second_horizontal_position,
+):
+    first_vertical = (
+        decimal.Decimal(str(first_position)),
+        decimal.Decimal(str(first_position)) + decimal.Decimal(str(first_height)),
+    )
+    second_vertical = (
+        decimal.Decimal(str(second_position)),
+        decimal.Decimal(str(second_position)) + decimal.Decimal(str(second_height)),
+    )
+    return intervals_overlap(first_vertical, second_vertical) and intervals_overlap(
+        horizontal_interval(first_width, first_horizontal_position),
+        horizontal_interval(second_width, second_horizontal_position),
+    )
+
+
+def _stored_width_position(device):
+    if not getattr(device, "pk", None):
+        return FULL_WIDTH, 1
+    try:
+        placement = device.netbox_utilities_rack_placement
+    except (AttributeError, ObjectDoesNotExist):
+        return FULL_WIDTH, 1
+    return placement.width, placement.horizontal_position
+
+
+def get_width_position(device, placements=None):
+    staged_width = getattr(device, "_netbox_utilities_rack_width", None)
+    staged_position = getattr(device, "_netbox_utilities_horizontal_position", None)
+    if staged_width is not None:
+        return normalize_width_position(staged_width, staged_position)
+    if placements is not None and device.pk in placements:
+        placement = placements[device.pk]
+        return placement.width, placement.horizontal_position
+    return _stored_width_position(device)
+
+
+def effective_width_positions(devices, placements=None):
+    """Return stored rack widths and infer missing rows for devices sharing one slot."""
+    devices = list(devices)
+    groups = defaultdict(list)
+    result = {}
+
+    for device in devices:
+        key = (
+            device.rack_id,
+            device.face,
+            decimal.Decimal(str(device.position)),
+            decimal.Decimal(str(device.device_type.u_height)),
+        )
+        groups[key].append(device)
+
+    for group in groups.values():
+        stored = {}
+        missing = []
+        for device in group:
+            if placements is not None:
+                placement = placements.get(device.pk)
+            else:
+                try:
+                    placement = device.netbox_utilities_rack_placement
+                except ObjectDoesNotExist:
+                    placement = None
+            if placement is None:
+                missing.append(device)
+            else:
+                stored[device.pk] = normalize_width_position(placement.width, placement.horizontal_position)
+
+        candidate_width = None
+        stored_widths = {width for width, _position in stored.values()}
+        if len(stored_widths) == 1:
+            stored_width = next(iter(stored_widths))
+            if len(group) <= stored_width:
+                candidate_width = stored_width
+        elif not stored and 2 <= len(group) <= 4:
+            candidate_width = len(group)
+
+        if candidate_width is not None:
+            used_positions = {position for width, position in stored.values() if width == candidate_width}
+            free_positions = iter(
+                position for position in range(1, candidate_width + 1) if position not in used_positions
+            )
+            for device in sorted(missing, key=lambda item: item.pk):
+                position = next(free_positions, None)
+                if position is None:
+                    break
+                result[device.pk] = (candidate_width, position, "inferred")
+
+        for device_id, (width, position) in stored.items():
+            result[device_id] = (width, position, "stored")
+        for device in missing:
+            result.setdefault(device.pk, (FULL_WIDTH, 1, "default"))
+
+    return result
+
+
+def stage_width_position(device, width, horizontal_position):
+    width, horizontal_position = normalize_width_position(width, horizontal_position)
+    device._netbox_utilities_rack_width = width
+    device._netbox_utilities_horizontal_position = horizontal_position
+    return width, horizontal_position
+
+
+def include_rack_width_in_fieldsets(fieldsets):
+    """Return an isolated fieldset layout which renders both rack width fields."""
+    if not fieldsets:
+        return fieldsets
+
+    copied_fieldsets = deepcopy(fieldsets)
+
+    def insert_after_position(group):
+        items = list(getattr(group, "items", ()))
+        if "position" in items:
+            index = items.index("position") + 1
+            for field_name in reversed(RACK_WIDTH_FORM_FIELDS):
+                if field_name not in items:
+                    items.insert(index, field_name)
+            group.items = tuple(items)
+            return True
+
+        for item in items:
+            nested_groups = getattr(item, "groups", ())
+            if any(insert_after_position(nested_group) for nested_group in nested_groups):
+                return True
+        return False
+
+    if any(insert_after_position(fieldset) for fieldset in copied_fieldsets):
+        return tuple(copied_fieldsets)
+
+    from utilities.forms.rendering import FieldSet
+
+    return (
+        *copied_fieldsets,
+        FieldSet(*RACK_WIDTH_FORM_FIELDS, name="Rackbreite im Rack"),
+    )
+
+
+def _vertical_interval(device, position=None):
+    start = decimal.Decimal(position if position is not None else device.position)
+    height = decimal.Decimal(str(device.device_type.u_height))
+    return start, start + height
+
+
+def _faces_overlap(first, second):
+    return bool(first.device_type.is_full_depth or second.device_type.is_full_depth or first.face == second.face)
+
+
+def _placement_map(device_ids):
+    return {
+        placement.device_id: placement for placement in DeviceRackPlacement.objects.filter(device_id__in=device_ids)
+    }
+
+
+def find_placement_conflict(device, *, position=None, exclude=None, ignore_excluded_devices=False):
+    if not getattr(device, "rack_id", None) or not (position if position is not None else device.position):
+        return None
+    try:
+        candidate_vertical = _vertical_interval(device, position)
+    except (AttributeError, ObjectDoesNotExist, TypeError, ValueError):
+        return None
+    candidate_horizontal = horizontal_interval(*get_width_position(device))
+
+    from dcim.models import Device
+
+    devices = Device.objects.filter(rack_id=device.rack_id, position__gte=1).select_related("device_type")
+    excluded_ids = set(exclude or ())
+    if device.pk:
+        excluded_ids.add(device.pk)
+    if excluded_ids:
+        devices = devices.exclude(pk__in=excluded_ids)
+    if ignore_excluded_devices:
+        devices = devices.exclude(device_type__exclude_from_utilization=True)
+    devices = list(devices)
+    placements = _placement_map([other.pk for other in devices])
+
+    for other in devices:
+        if not _faces_overlap(device, other):
+            continue
+        other_horizontal = horizontal_interval(*get_width_position(other, placements))
+        if intervals_overlap(candidate_vertical, _vertical_interval(other)) and intervals_overlap(
+            candidate_horizontal,
+            other_horizontal,
+        ):
+            return other
+    return None
+
+
+def validate_device_placement(device):
+    if not getattr(device, "rack_id", None) or not getattr(device, "position", None):
+        return
+    width, horizontal_position = get_width_position(device)
+    normalize_width_position(width, horizontal_position)
+    if conflict := find_placement_conflict(device):
+        raise ValidationError(
+            {
+                "position": (
+                    f"U{device.position} überschneidet sich in der Rackbreite mit dem Gerät {conflict}. "
+                    "Wählen Sie eine freie Breitenposition."
+                )
+            }
+        )
+
+
+def available_units_for_device(rack, device, *, exclude=None, ignore_excluded_devices=False):
+    try:
+        height = decimal.Decimal(str(device.device_type.u_height))
+    except (AttributeError, ObjectDoesNotExist):
+        return []
+    if not device.position:
+        return []
+    units = list(rack.units)
+    required = set(_decimal_range(device.position, decimal.Decimal(device.position) + height))
+    if not required.issubset(units):
+        return []
+    conflict = find_placement_conflict(
+        device,
+        exclude=exclude,
+        ignore_excluded_devices=ignore_excluded_devices,
+    )
+    return [device.position] if conflict is None else []
+
+
+def _decimal_range(start, stop):
+    current = decimal.Decimal(start)
+    stop = decimal.Decimal(stop)
+    while current < stop:
+        yield current
+        current += decimal.Decimal("0.5")
+
+
+def _install_rack_methods():
+    from dcim.models import Rack
+
+    # Version 0.9.0 replaced get_rack_units() globally. A long-running
+    # process which reloads the plugin must restore NetBox's native method
+    # before installing the current, non-destructive implementation.
+    already_installed = getattr(Rack, "_netbox_utilities_rack_width_installed", False)
+    installed_version = getattr(Rack, "_netbox_utilities_rack_width_version", None)
+    if already_installed and installed_version is None:
+        for method_name in ("get_rack_units", "get_available_units"):
+            method = getattr(Rack, method_name)
+            if wrapped := getattr(method, "__wrapped__", None):
+                setattr(Rack, method_name, wrapped)
+        already_installed = False
+
+    if already_installed:
+        Rack._netbox_utilities_rack_width_version = 2
+        return
+    original_available_units = Rack.get_available_units
+
+    @wraps(original_available_units)
+    def width_aware_available_units(
+        rack,
+        u_height=1.0,
+        rack_face=None,
+        exclude=None,
+        ignore_excluded_devices=False,
+    ):
+        device = _validated_device.get()
+        if device is not None and getattr(device, "rack_id", None) == rack.pk:
+            return available_units_for_device(
+                rack,
+                device,
+                exclude=exclude,
+                ignore_excluded_devices=ignore_excluded_devices,
+            )
+        return original_available_units(rack, u_height, rack_face, exclude, ignore_excluded_devices)
+
+    Rack.get_available_units = width_aware_available_units
+    Rack._netbox_utilities_rack_width_installed = True
+    Rack._netbox_utilities_rack_width_version = 2
+
+
+def _install_device_validation():
+    from dcim.models import Device
+
+    if getattr(Device, "_netbox_utilities_rack_width_installed", False):
+        return
+    original_clean = Device.clean
+
+    @wraps(original_clean)
+    def width_aware_clean(device, *args, **kwargs):
+        token = _validated_device.set(device)
+        try:
+            result = original_clean(device, *args, **kwargs)
+        finally:
+            _validated_device.reset(token)
+        validate_device_placement(device)
+        return result
+
+    Device.clean = width_aware_clean
+    Device._meta.constraints = tuple(
+        constraint
+        for constraint in Device._meta.constraints
+        if not (
+            constraint.name == CORE_RACK_POSITION_CONSTRAINT
+            or tuple(getattr(constraint, "fields", ())) == ("rack", "position", "face")
+        )
+    )
+    Device._meta.__dict__.pop("total_unique_constraints", None)
+    Device._netbox_utilities_rack_width_installed = True
+
+
+def _install_device_form():
+    from dcim.views import DeviceEditView
+    from netbox.registry import registry
+
+    if getattr(DeviceEditView, "_netbox_utilities_rack_width_installed", False):
+        return
+
+    base_device_form = DeviceEditView.form
+
+    class RackWidthDeviceForm(base_device_form):
+        utilities_rack_width = forms.ChoiceField(
+            label="Rackbreite",
+            choices=WIDTH_CHOICES,
+            required=False,
+            initial=FULL_WIDTH,
+            help_text="Optional: Geräte können sich eine HE nebeneinander teilen.",
+        )
+        utilities_horizontal_position = forms.ChoiceField(
+            label="Breitenposition",
+            choices=POSITION_CHOICES,
+            required=False,
+            initial=1,
+            help_text="Position von links; bei halber Breite sind Position 1 und 2 möglich.",
+        )
+
+        @property
+        def fieldsets(self):
+            return include_rack_width_in_fieldsets(super().fieldsets)
+
+        def __init__(self, *args, **kwargs):
+            super().__init__(*args, **kwargs)
+            width, horizontal_position = _stored_width_position(self.instance)
+            if not self.is_bound:
+                self.initial["utilities_rack_width"] = width
+                self.initial["utilities_horizontal_position"] = horizontal_position
+
+            reordered = {}
+            for name, field in self.fields.items():
+                if name in {"utilities_rack_width", "utilities_horizontal_position"}:
+                    continue
+                reordered[name] = field
+                if name == "position":
+                    reordered["utilities_rack_width"] = self.fields["utilities_rack_width"]
+                    reordered["utilities_horizontal_position"] = self.fields["utilities_horizontal_position"]
+            self.fields = reordered
+
+        def clean(self):
+            super().clean()
+            cleaned_data = self.cleaned_data
+            try:
+                width, horizontal_position = normalize_width_position(
+                    cleaned_data.get("utilities_rack_width"),
+                    cleaned_data.get("utilities_horizontal_position"),
+                )
+            except ValidationError as error:
+                self.add_error("utilities_horizontal_position", error)
+                return cleaned_data
+            if not cleaned_data.get("rack") or not cleaned_data.get("position"):
+                width, horizontal_position = FULL_WIDTH, 1
+            cleaned_data["utilities_rack_width"] = width
+            cleaned_data["utilities_horizontal_position"] = horizontal_position
+            stage_width_position(self.instance, width, horizontal_position)
+            return cleaned_data
+
+        def save(self, commit=True):
+            device = super().save(commit=commit)
+            if not commit:
+                return device
+            width, horizontal_position = get_width_position(device)
+            if width == FULL_WIDTH or not device.rack_id or not device.position:
+                DeviceRackPlacement.objects.filter(device=device).delete()
+            else:
+                DeviceRackPlacement.objects.update_or_create(
+                    device=device,
+                    defaults={"width": width, "horizontal_position": horizontal_position},
+                )
+            return device
+
+    RackWidthDeviceForm.__module__ = __name__
+    RackWidthDeviceForm.__qualname__ = "RackWidthDeviceForm"
+
+    class RackWidthDeviceEditView(DeviceEditView):
+        form = RackWidthDeviceForm
+        template_name = "netbox_utilities/device_edit.html"
+        htmx_template_name = "netbox_utilities/device_edit_form.html"
+
+    RackWidthDeviceEditView.__module__ = __name__
+    RackWidthDeviceEditView.__qualname__ = "RackWidthDeviceEditView"
+
+    replaced_views = set()
+    for view_config in registry["views"]["dcim"]["device"]:
+        if view_config["name"] in {"add", "edit"}:
+            view_config["view"] = RackWidthDeviceEditView
+            replaced_views.add(view_config["name"])
+    if replaced_views != {"add", "edit"}:
+        missing_views = ", ".join(sorted({"add", "edit"} - replaced_views))
+        logger.warning(
+            "NetBox Utilities could not replace these device registry views: %s; "
+            "the core DeviceEditView fallback remains active",
+            missing_views,
+        )
+
+    DeviceEditView.form = RackWidthDeviceForm
+    DeviceEditView.template_name = RackWidthDeviceEditView.template_name
+    DeviceEditView.htmx_template_name = RackWidthDeviceEditView.htmx_template_name
+    DeviceEditView._netbox_utilities_rack_width_installed = True
+
+
+def _install_rack_svg():
+    from dcim.svg.racks import RackElevationSVG
+
+    if getattr(RackElevationSVG, "_netbox_utilities_rack_width_version", None) == 4:
+        return
+    current_draw_face = RackElevationSVG.draw_face
+    current_globals = getattr(current_draw_face, "__globals__", {})
+    if current_globals.get("__name__") == __name__ and hasattr(current_draw_face, "__wrapped__"):
+        original_draw_face = current_draw_face.__wrapped__
+    else:
+        original_draw_face = current_draw_face
+
+    @wraps(original_draw_face)
+    def width_aware_draw_face(elevation, face, opposite=False):
+        from svgwrite.shapes import Rect
+
+        # NetBox's get_rack_units() stores only one device per rack unit and
+        # therefore cannot represent two devices mounted beside each other.
+        # Query every mounted device directly and render each exactly once.
+        devices = list(_rack_elevation_devices(elevation.rack, face))
+        widths = effective_width_positions(devices)
+        for device in devices:
+            width_divisor, horizontal_position, _source = widths[device.pk]
+            height = decimal.Decimal(str(device.device_type.u_height))
+            coords = elevation._get_device_coords(device.position, height)
+            width = elevation.unit_width / width_divisor
+            coords = (coords[0] + width * (horizontal_position - 1), coords[1])
+            size = (width, int(elevation.unit_height * height))
+            if device.pk in elevation.permitted_device_ids:
+                if device.face == face and not opposite:
+                    elevation.draw_device_front(device, coords, size)
+                else:
+                    elevation.draw_device_rear(device, coords, size)
+            else:
+                elevation.drawing.add(Rect(coords, size, class_="blocked"))
+
+    RackElevationSVG.draw_face = width_aware_draw_face
+    RackElevationSVG._netbox_utilities_rack_width_installed = True
+    RackElevationSVG._netbox_utilities_rack_width_version = 4
+
+
+def _rack_elevation_devices(rack, face):
+    """Return every annotated device which must be drawn on a rack face."""
+    from dcim.models import Device
+
+    return (
+        Device.objects.filter(
+            rack=rack,
+            position__gt=0,
+            device_type__u_height__gt=0,
+        )
+        .filter(Q(face=face) | Q(device_type__is_full_depth=True))
+        .select_related(
+            "device_type",
+            "device_type__manufacturer",
+            "role",
+            "virtual_chassis",
+            "netbox_utilities_rack_placement",
+        )
+        .annotate(devicebay_count=Count("devicebays"))
+        .order_by("position", "pk")
+    )
+
+
+def _validate_before_save(sender, instance, raw=False, **kwargs):
+    if not raw:
+        using = kwargs.get("using")
+        if instance.rack_id:
+            from dcim.models import Rack
+            from django.db import transaction
+
+            connection = transaction.get_connection(using)
+            if connection.in_atomic_block:
+                Rack.objects.using(using).select_for_update().filter(pk=instance.rack_id).exists()
+        validate_device_placement(instance)
+
+
+def _cleanup_unracked_placement(sender, instance, raw=False, using=None, **kwargs):
+    if not raw and (not instance.rack_id or not instance.position):
+        DeviceRackPlacement.objects.using(using).filter(device_id=instance.pk).delete()
+
+
+def install_rack_width_support():
+    from dcim.models import Device
+
+    _install_rack_methods()
+    _install_device_validation()
+    _install_device_form()
+    _install_rack_svg()
+    pre_save.connect(
+        _validate_before_save,
+        sender=Device,
+        dispatch_uid="netbox_utilities.validate_device_rack_width",
+        weak=False,
+    )
+    post_save.connect(
+        _cleanup_unracked_placement,
+        sender=Device,
+        dispatch_uid="netbox_utilities.cleanup_device_rack_width",
+        weak=False,
+    )

netbox_utilities/reorder_rack.py

@@ -5,19 +5,27 @@ from importlib import import_module
 
 from dcim.models import Device, Rack
 from django.apps import apps
-from django.core.exceptions import ValidationError
-from django.db import transaction
+from django.core.exceptions import ObjectDoesNotExist, ValidationError
+from django.db import OperationalError, ProgrammingError, transaction
 from django.http import Http404
 from django.shortcuts import get_object_or_404
+from netbox.plugins import get_plugin_config
 from rest_framework import status
 from rest_framework.exceptions import PermissionDenied
 from rest_framework.response import Response
 from utilities.permissions import get_permission_for_model
 
+from . import __version__
+from .models import DeviceRackPlacement
+from .rack_width import FULL_WIDTH, effective_width_positions, normalize_width_position, stage_width_position
+
 logger = logging.getLogger(__name__)
 
 SUPPORTED_REORDER_RACK_VERSIONS = {"1.1.4"}
 PATCH_MARKER = "_netbox_utilities_bulk_save"
+VIEW_PATCH_MARKER = "_netbox_utilities_width_aware_view"
+GRID_COLUMNS = 12
+REORDER_RACK_VIEW = "dcim:rack_reorder"
 
 
 class RackLayoutError(Exception):
@@ -29,9 +37,31 @@ class DevicePlacement:
     device_id: int
     position: Decimal | None
     face: str
+    grid_x: int | None
 
 
-def parse_device_placements(layout):
+def grid_dimensions(width, horizontal_position):
+    try:
+        width, horizontal_position = normalize_width_position(width, horizontal_position)
+    except ValidationError as error:
+        raise RackLayoutError(str(error)) from error
+    grid_width = GRID_COLUMNS // width
+    return grid_width, (horizontal_position - 1) * grid_width
+
+
+def horizontal_position_from_grid_x(width, grid_x):
+    if isinstance(grid_x, bool) or not isinstance(grid_x, int):
+        raise RackLayoutError("Die horizontale Rasterposition muss eine ganze Zahl sein.")
+    grid_width, _ = grid_dimensions(width, 1)
+    if grid_x < 0 or grid_x > GRID_COLUMNS - grid_width or grid_x % grid_width:
+        raise RackLayoutError(f"Rasterposition {grid_x} ist für 1/{width} Rackbreite nicht zulässig.")
+    return grid_x // grid_width + 1
+
+
+def parse_device_placements(layout, *, grid_columns=None):
+    if grid_columns not in {None, GRID_COLUMNS}:
+        raise RackLayoutError(f"Das Rackraster muss {GRID_COLUMNS} Spalten verwenden.")
+
     placements = []
     seen_device_ids = set()
 
@@ -53,6 +83,7 @@ def parse_device_placements(layout):
 
             if section == "other":
                 position = None
+                grid_x = None
             else:
                 try:
                     position = Decimal(str(item["y"]))
@@ -61,7 +92,13 @@ def parse_device_placements(layout):
                 if not position.is_finite():
                     raise RackLayoutError(f"Gerät {device_id} besitzt keine gültige Rack-Position.")
 
-            placements.append(DevicePlacement(device_id=device_id, position=position, face=face))
+                grid_x = None
+                if grid_columns == GRID_COLUMNS:
+                    grid_x = item.get("x")
+                    if isinstance(grid_x, bool) or not isinstance(grid_x, int) or not 0 <= grid_x < GRID_COLUMNS:
+                        raise RackLayoutError(f"Gerät {device_id} besitzt keine gültige horizontale Rasterposition.")
+
+            placements.append(DevicePlacement(device_id=device_id, position=position, face=face, grid_x=grid_x))
 
     return placements
 
@@ -77,35 +114,84 @@ def apply_rack_layout(*, rack, placements, user):
         missing = ", ".join(str(device_id) for device_id in sorted(missing_ids))
         raise RackLayoutError(f"Diese Geräte gehören nicht zum gewählten Rack: {missing}.")
 
+    stored_placements = {
+        placement.device_id: placement
+        for placement in DeviceRackPlacement.objects.select_for_update().filter(device_id__in=placement_by_id)
+    }
+    mounted_devices = [device for device in devices.values() if device.position is not None and device.position > 0]
+    effective_placements = effective_width_positions(mounted_devices, stored_placements)
+    target_placements = []
+    for placement in placements:
+        current_width, current_horizontal_position, _source = effective_placements.get(
+            placement.device_id,
+            (FULL_WIDTH, 1, "default"),
+        )
+        if placement.position is None:
+            target_width, target_horizontal_position = FULL_WIDTH, 1
+        elif placement.grid_x is None:
+            target_width = current_width
+            target_horizontal_position = current_horizontal_position
+        else:
+            target_width = current_width
+            target_horizontal_position = horizontal_position_from_grid_x(target_width, placement.grid_x)
+        target_placements.append(
+            (
+                devices[placement.device_id],
+                placement,
+                target_width,
+                target_horizontal_position,
+                current_width,
+                current_horizontal_position,
+            )
+        )
+
     changed = [
-        (devices[placement.device_id], placement)
-        for placement in placements
+        (device, placement, target_width, target_horizontal_position)
+        for (
+            device,
+            placement,
+            target_width,
+            target_horizontal_position,
+            current_width,
+            current_horizontal_position,
+        ) in target_placements
         if (
-            devices[placement.device_id].position != placement.position
-            or devices[placement.device_id].face != placement.face
+            device.position != placement.position
+            or device.face != placement.face
+            or current_width != target_width
+            or current_horizontal_position != target_horizontal_position
         )
     ]
     if not changed:
         return []
 
     permission = get_permission_for_model(Device, "change")
-    for device, _placement in changed:
+    for device, _placement, _width, _horizontal_position in changed:
         if not user.has_perm(permission, obj=device):
             raise PermissionDenied(f"Keine Berechtigung zum Verschieben von {device}.")
 
-    for device, _placement in changed:
+    for device, _placement, _width, _horizontal_position in changed:
         device.snapshot()
 
-    changed_ids = [device.pk for device, _placement in changed]
+    changed_ids = [device.pk for device, _placement, _width, _horizontal_position in changed]
     Device.objects.filter(pk__in=changed_ids).update(position=None, face="")
 
-    for device, placement in changed:
+    for device, placement, width, horizontal_position in changed:
         device.position = placement.position
         device.face = placement.face
+        stage_width_position(device, width, horizontal_position)
         device.full_clean()
         device.save()
 
-    return [device for device, _placement in changed]
+        if width == FULL_WIDTH or placement.position is None:
+            DeviceRackPlacement.objects.filter(device=device).delete()
+        else:
+            DeviceRackPlacement.objects.update_or_create(
+                device=device,
+                defaults={"width": width, "horizontal_position": horizontal_position},
+            )
+
+    return [device for device, _placement, _width, _horizontal_position in changed]
 
 
 def _validation_error_message(error):
@@ -117,6 +203,149 @@ def _validation_error_message(error):
     return "; ".join(str(message) for message in error.messages)
 
 
+def is_reorder_rack_request(request):
+    resolver_match = getattr(request, "resolver_match", None)
+    return getattr(resolver_match, "view_name", None) == REORDER_RACK_VIEW
+
+
+def reorder_rack_width_enabled(request):
+    if not (
+        is_reorder_rack_request(request)
+        and get_plugin_config("netbox_utilities", "reorder_rack_bulk_save_enabled")
+        and apps.is_installed("netbox_reorder_rack")
+    ):
+        return False
+    plugin_config = apps.get_app_config("netbox_reorder_rack")
+    return getattr(plugin_config, "version", None) in SUPPORTED_REORDER_RACK_VERSIONS
+
+
+def reorder_grid_y(rack, position, height):
+    rack_height = int(Decimal(str(rack.u_height)) * 2)
+    grid_height = int(Decimal(str(height)) * 2)
+    unit_id = int(Decimal(str(position)) * 2)
+    if rack.desc_units:
+        return unit_id - 2
+    if grid_height > 1:
+        return rack_height - unit_id - grid_height + 2
+    return rack_height - unit_id
+
+
+def _image_url(image):
+    if not image:
+        return ""
+    try:
+        return image.url
+    except (AttributeError, ValueError):
+        return ""
+
+
+def _device_label(device):
+    return device.label or str(device.device_type)
+
+
+def _empty_reorder_rack_width_data(request, *, status="ready"):
+    selected_view = request.GET.get("view", "images-and-labels")
+    return {
+        "columns": GRID_COLUMNS,
+        "unit_width": 220,
+        "images": selected_view != "labels-only",
+        "labels": selected_view != "images-only",
+        "devices": [],
+        "status": status,
+        "schema_version": 3,
+        "complete": False,
+    }
+
+
+def get_reorder_rack_width_data(request, *, rack=None, devices=None):
+    """Describe every mounted widget for netbox-reorder-rack's GridStack UI."""
+    # The patched Reorder view passes its already-authorized rack and device
+    # queryset explicitly.  The global helper keeps the permission-scoped
+    # lookup for callers which do not own the rendered view.
+    view_owned_data = rack is not None
+    if not view_owned_data and not reorder_rack_width_enabled(request):
+        return None
+
+    data = _empty_reorder_rack_width_data(request)
+    rack_id = rack.pk if rack is not None else getattr(request.resolver_match, "kwargs", {}).get("pk")
+    if not rack_id:
+        data["status"] = "missing-rack"
+        return data
+
+    from netbox.config import get_config
+    from utilities.html import foreground_color
+
+    try:
+        if rack is None:
+            rack = Rack.objects.restrict(request.user, "view").filter(pk=rack_id).first()
+        if rack is None:
+            return None
+        if devices is None:
+            devices = (
+                Device.objects.restrict(request.user, "view")
+                .filter(
+                    rack=rack,
+                    position__gt=0,
+                    device_type__u_height__gt=0,
+                )
+                .select_related(
+                    "device_type",
+                    "device_type__manufacturer",
+                    "role",
+                    "virtual_chassis",
+                    "netbox_utilities_rack_placement",
+                )
+                .order_by("position", "pk")
+            )
+        devices = list(devices)
+        widths = effective_width_positions(devices)
+        permission = get_permission_for_model(Device, "change")
+        for device in devices:
+            width, horizontal_position, width_source = widths[device.pk]
+            grid_width, grid_x = grid_dimensions(width, horizontal_position)
+            role_color = device.role.color or "1685fc"
+            grid_height = int(Decimal(str(device.device_type.u_height)) * 2)
+            data["devices"].append(
+                {
+                    "id": device.pk,
+                    "label": _device_label(device),
+                    "face": device.face,
+                    "full_depth": device.device_type.is_full_depth,
+                    "grid_x": grid_x,
+                    "grid_y": reorder_grid_y(rack, device.position, device.device_type.u_height),
+                    "grid_width": grid_width,
+                    "grid_height": grid_height,
+                    "width": width,
+                    "horizontal_position": horizontal_position,
+                    "width_source": width_source,
+                    "color": role_color,
+                    "text_color": foreground_color(role_color),
+                    "front_image": _image_url(device.device_type.front_image),
+                    "rear_image": _image_url(device.device_type.rear_image),
+                    "locked": not request.user.has_perm(permission, obj=device),
+                }
+            )
+        data["unit_width"] = get_config().RACK_ELEVATION_DEFAULT_UNIT_WIDTH
+        data["complete"] = True
+        return data
+    except (
+        AttributeError,
+        ObjectDoesNotExist,
+        OperationalError,
+        ProgrammingError,
+        RackLayoutError,
+        TypeError,
+        ValueError,
+    ):
+        logger.warning(
+            "Could not load partial rack widths for netbox-reorder-rack rack %s; using the native rack layout",
+            rack_id,
+            exc_info=True,
+        )
+        data["status"] = "native-fallback"
+        return data
+
+
 def bulk_reorder_update(self, request, pk=None):
     serializer = self.serializer_class(data=request.data)
     serializer.is_valid(raise_exception=True)
@@ -128,7 +357,12 @@ def bulk_reorder_update(self, request, pk=None):
             if layout["rack_id"] != rack.pk:
                 raise RackLayoutError("Die Rack-ID der Anfrage stimmt nicht mit dem Ziel-Rack überein.")
 
-            placements = parse_device_placements(layout)
+            grid_columns_header = request.headers.get("X-NetBox-Utilities-Rack-Grid-Columns")
+            try:
+                grid_columns = int(grid_columns_header) if grid_columns_header is not None else None
+            except (TypeError, ValueError):
+                raise RackLayoutError("Das angegebene Rackraster ist ungültig.") from None
+            placements = parse_device_placements(layout, grid_columns=grid_columns)
             changed_devices = apply_rack_layout(rack=rack, placements=placements, user=request.user)
             if not changed_devices:
                 return Response(
@@ -168,6 +402,60 @@ def bulk_reorder_update(self, request, pk=None):
         )
 
 
+def width_aware_reorder_get(self, request, pk):
+    """Render every rack device server-side on the native Reorder page."""
+    from dcim.choices import SubdeviceRoleChoices
+    from django.conf import settings
+    from django.shortcuts import render
+
+    rack = get_object_or_404(Rack, pk=pk)
+    selected_view = request.GET.get("view", "images-and-labels")
+    images = selected_view != "labels-only"
+    labels = selected_view != "images-only"
+    non_racked = (
+        Device.objects.filter(rack=rack, position__isnull=True, parent_bay__isnull=True)
+        .exclude(device_type__subdevice_role=SubdeviceRoleChoices.ROLE_CHILD)
+        .select_related("device_type", "role")
+    )
+    mounted_devices = (
+        Device.objects.filter(
+            rack=rack,
+            position__gt=0,
+            device_type__u_height__gt=0,
+        )
+        .select_related(
+            "device_type",
+            "device_type__manufacturer",
+            "role",
+            "virtual_chassis",
+            "netbox_utilities_rack_placement",
+        )
+        .order_by("position", "pk")
+    )
+    width_data = get_reorder_rack_width_data(request, rack=rack, devices=mounted_devices)
+    if not width_data or not width_data.get("complete"):
+        original_get = getattr(type(self), "_netbox_utilities_original_get", None)
+        if original_get is not None:
+            return original_get(self, request, pk)
+        raise Http404
+
+    return render(
+        request,
+        "netbox_utilities/reorder_rack.html",
+        {
+            "object": rack,
+            "images": images,
+            "labels": labels,
+            "unit_width": width_data["unit_width"],
+            "reorder_devices": width_data["devices"],
+            "reorder_rack_width_data": width_data,
+            "non_racked": non_racked,
+            "basepath": settings.BASE_PATH,
+            "asset_version": __version__,
+        },
+    )
+
+
 def install_reorder_rack_bulk_save():
     if not apps.is_installed("netbox_reorder_rack"):
         return False
@@ -182,13 +470,19 @@ def install_reorder_rack_bulk_save():
         )
         return False
 
-    views = import_module("netbox_reorder_rack.api.views")
-    save_viewset = views.SaveViewSet
-    if getattr(save_viewset, PATCH_MARKER, False):
-        return True
+    api_views = import_module("netbox_reorder_rack.api.views")
+    save_viewset = api_views.SaveViewSet
+    if not getattr(save_viewset, PATCH_MARKER, False):
+        save_viewset._netbox_utilities_original_update = save_viewset.update
+        save_viewset.update = bulk_reorder_update
+        setattr(save_viewset, PATCH_MARKER, True)
+
+    page_views = import_module("netbox_reorder_rack.views")
+    reorder_view = page_views.ReorderView
+    if not getattr(reorder_view, VIEW_PATCH_MARKER, False):
+        reorder_view._netbox_utilities_original_get = reorder_view.get
+        reorder_view.get = width_aware_reorder_get
+        setattr(reorder_view, VIEW_PATCH_MARKER, True)
 
-    save_viewset._netbox_utilities_original_update = save_viewset.update
-    save_viewset.update = bulk_reorder_update
-    setattr(save_viewset, PATCH_MARKER, True)
     logger.info("Enabled atomic multi-device saving for netbox-reorder-rack %s", plugin_version)
     return True

netbox_utilities/runtime.py

@@ -11,6 +11,10 @@ def navigation_customization_enabled():
     return bool(get_plugin_config("netbox_utilities", "navigation_customization_enabled"))
 
 
+def connection_vlans_enabled():
+    return bool(get_plugin_config("netbox_utilities", "connection_vlans_enabled"))
+
+
 def tenant_filter_enabled():
     if not get_plugin_config("netbox_utilities", "tenant_filter_enabled"):
         return False

netbox_utilities/static/netbox_utilities/forms.js

@@ -91,10 +91,41 @@
     });
   }
 
+  function configureRackWidth(root = document) {
+    const widthField = root.querySelector('[name="utilities_rack_width"]');
+    const positionField = root.querySelector('[name="utilities_horizontal_position"]');
+    if (!widthField || !positionField || widthField.dataset.netboxUtilitiesWidth === 'true') return;
+    widthField.dataset.netboxUtilitiesWidth = 'true';
+
+    const updatePositions = () => {
+      const width = Number.parseInt(widthField.value || '1', 10);
+      Array.from(positionField.options).forEach((option) => {
+        const position = Number.parseInt(option.value || '1', 10);
+        option.disabled = position > width;
+      });
+
+      const resetPosition = width === 1 || Number.parseInt(positionField.value || '1', 10) > width;
+      if (resetPosition) {
+        positionField.value = '1';
+      }
+
+      positionField.disabled = width === 1;
+      if (positionField.tomselect) positionField.tomselect.sync();
+
+      if (resetPosition) {
+        positionField.dispatchEvent(new Event('change', {bubbles: true}));
+      }
+    };
+
+    widthField.addEventListener('change', updatePositions);
+    updatePositions();
+  }
+
   function initialize(root = document) {
     rewriteImageUploadLinks(root);
     configureTenantConfirmation(root);
     configureImagePreview(root);
+    configureRackWidth(root);
   }
 
   if (document.readyState === 'loading') {

netbox_utilities/static/netbox_utilities/netbox_utilities.css

@@ -29,6 +29,51 @@
   white-space: nowrap;
 }
 
+.rack-device.netbox-utilities-partial-width {
+  box-sizing: border-box;
+  right: auto !important;
+  left: calc(var(--netbox-utilities-rack-device-left) + 3px) !important;
+  width: calc(var(--netbox-utilities-rack-device-width) - 6px) !important;
+}
+
+/*
+ * netbox-reorder-rack 1.1.4 bundles GridStack 10, while NetBox 4.6.7
+ * provides GridStack 11's base stylesheet. GridStack 11 calculates item
+ * widths through a CSS variable which the older runtime never sets. Without
+ * these explicit rules every 12-column widget therefore has width: 0px.
+ * Do not mark these declarations important: while dragging, GridStack writes
+ * pixel coordinates inline on a fixed-position helper. Those inline values
+ * must take precedence or the helper is sized relative to the viewport.
+ */
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item {
+  width: calc(100% / 12);
+}
+
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="2"] { width: calc(200% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="3"] { width: 25%; }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="4"] { width: calc(400% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="5"] { width: calc(500% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="6"] { width: 50%; }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="7"] { width: calc(700% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="8"] { width: calc(800% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="9"] { width: 75%; }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="10"] { width: calc(1000% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="11"] { width: calc(1100% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-w="12"] { width: 100%; }
+
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="0"] { left: 0; }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="1"] { left: calc(100% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="2"] { left: calc(200% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="3"] { left: 25%; }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="4"] { left: calc(400% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="5"] { left: calc(500% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="6"] { left: 50%; }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="7"] { left: calc(700% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="8"] { left: calc(800% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="9"] { left: 75%; }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="10"] { left: calc(1000% / 12); }
+.netbox-utilities-reorder-grid[gs-column="12"] > .grid-stack-item[gs-x="11"] { left: calc(1100% / 12); }
+
 .netbox-utilities-sidebar-resizer {
   display: none;
 }

netbox_utilities/static/netbox_utilities/reorder-rack-width.js

@@ -0,0 +1,188 @@
+(() => {
+  'use strict';
+
+  const source = document.getElementById('netbox-utilities-reorder-rack-width-data');
+  if (!source) return;
+
+  let data;
+  try {
+    data = JSON.parse(source.textContent);
+  } catch (error) {
+    console.error('NetBox Utilities could not read the Reorder Rack width data.', error);
+    return;
+  }
+  if (data.status && data.status !== 'ready') {
+    console.warn('NetBox Utilities is leaving Reorder Rack in its native layout.', data.status);
+    return;
+  }
+  if (data.schema_version !== 3 || data.complete !== true || !Array.isArray(data.devices)) {
+    console.warn('NetBox Utilities received an incomplete Reorder Rack payload and kept the native layout.');
+    return;
+  }
+  const validDeviceData = data.devices.every(device => (
+    Number.isInteger(Number(device.id))
+    && ['front', 'rear'].includes(device.face)
+    && Number.isInteger(Number(device.grid_x))
+    && Number.isInteger(Number(device.grid_y))
+    && Number.isInteger(Number(device.grid_width))
+    && Number.isInteger(Number(device.grid_height))
+  ));
+  if (!validDeviceData) {
+    console.warn('NetBox Utilities received invalid Reorder Rack device data and kept the native layout.');
+    return;
+  }
+
+  const columns = Number.parseInt(data.columns, 10) || 12;
+  const gridElements = {
+    front: document.getElementById('grid-front'),
+    rear: document.getElementById('grid-rear'),
+    other: document.getElementById('grid-other'),
+  };
+  if (!gridElements.front || !gridElements.rear || !gridElements.other) return;
+
+  const nativeMountedItems = [
+    ...gridElements.front.querySelectorAll('.grid-stack-item'),
+    ...gridElements.rear.querySelectorAll('.grid-stack-item'),
+  ];
+  if (!data.devices.length && nativeMountedItems.length) {
+    console.warn('NetBox Utilities received no replacement devices and kept the populated native layout.');
+    return;
+  }
+  const devicesById = new Map(data.devices.map(device => [String(device.id), device]));
+  const nativeItemsByFace = {};
+
+  const setAttribute = (element, name, value) => element.setAttribute(name, String(value));
+  const originalFetch = window.fetch.bind(window);
+  window.fetch = (resource, options = {}) => {
+    const resourceUrl = typeof resource === 'string' || resource instanceof URL
+      ? resource
+      : resource?.url;
+    let url;
+    try {
+      url = new URL(resourceUrl, document.baseURI);
+    } catch (_) {
+      return originalFetch(resource, options);
+    }
+    const method = String(options.method || resource?.method || 'GET').toUpperCase();
+    if (method !== 'PUT' || !/\/api\/plugins\/reorder\/save\/\d+\/?$/.test(url.pathname)) {
+      return originalFetch(resource, options);
+    }
+
+    const headers = new Headers(options.headers || resource?.headers);
+    headers.set('X-NetBox-Utilities-Rack-Grid-Columns', String(columns));
+    return originalFetch(resource, {...options, headers});
+  };
+
+  Object.entries(gridElements).forEach(([face, grid]) => {
+    setAttribute(grid, 'gs-column', columns);
+    const nativeItemsById = new Map(
+      Array.from(grid.querySelectorAll('.grid-stack-item')).map(item => [item.getAttribute('gs-id'), item]),
+    );
+    grid.querySelectorAll('.grid-stack-item').forEach(item => {
+      // Keep every native widget whenever possible. Rack.get_rack_units() can
+      // expose only one device per unit, so missing shared widgets are added
+      // from the complete payload below.
+      if (face !== 'other') {
+        const device = devicesById.get(item.getAttribute('gs-id'));
+        const belongsOnFace = device && (device.face === face || device.full_depth);
+        if (!belongsOnFace) {
+          item.remove();
+          return;
+        }
+        setAttribute(item, 'gs-w', device.grid_width);
+        setAttribute(item, 'gs-h', device.grid_height);
+        setAttribute(item, 'gs-x', device.grid_x);
+        setAttribute(item, 'gs-y', device.grid_y);
+        item.dataset.rackWidth = String(device.width);
+        item.dataset.horizontalPosition = String(device.horizontal_position);
+        return;
+      }
+      setAttribute(item, 'gs-w', columns);
+      setAttribute(item, 'gs-x', 0);
+      item.dataset.rackWidth = '1';
+      item.dataset.horizontalPosition = '1';
+    });
+    nativeItemsByFace[face] = nativeItemsById;
+  });
+
+  const addWidget = (device, gridFace, itemFace, rearSide = false) => {
+    const item = document.createElement('div');
+    item.className = 'grid-stack-item netbox-utilities-reorder-rack-device';
+    setAttribute(item, 'gs-w', device.grid_width);
+    setAttribute(item, 'gs-h', device.grid_height);
+    setAttribute(item, 'gs-x', device.grid_x);
+    setAttribute(item, 'gs-y', device.grid_y);
+    setAttribute(item, 'gs-id', device.id);
+    setAttribute(item, 'gs-locked', device.locked ? 'true' : 'false');
+    setAttribute(item, 'gs-no-move', device.locked ? 'true' : 'false');
+    item.dataset.itemColor = device.color;
+    item.dataset.itemTextColor = device.text_color;
+    item.dataset.fullDepth = device.full_depth ? 'True' : 'False';
+    item.dataset.itemFace = itemFace;
+    item.dataset.rackWidth = String(device.width);
+    item.dataset.horizontalPosition = String(device.horizontal_position);
+
+    const content = document.createElement('div');
+    content.className = 'grid-stack-item-content';
+    if (rearSide) content.classList.add('device_rear');
+    const image = rearSide ? device.rear_image : device.front_image;
+    if (image && data.images) {
+      content.style.backgroundImage = `url("${String(image).replaceAll('"', '\\"')}")`;
+      content.style.backgroundSize = `${data.unit_width}px`;
+      content.style.color = `#${device.text_color}`;
+      if (data.labels) content.textContent = device.label;
+    } else {
+      if (!rearSide) content.style.backgroundColor = `#${device.color}`;
+      content.style.color = rearSide ? '#000000' : `#${device.text_color}`;
+      content.textContent = device.label;
+    }
+    item.appendChild(content);
+    gridElements[gridFace].appendChild(item);
+  };
+
+  data.devices.forEach(device => {
+    const face = device.face === 'rear' ? 'rear' : 'front';
+    if (!nativeItemsByFace[face].has(String(device.id))) {
+      addWidget(device, face, face);
+    }
+    if (device.full_depth) {
+      const oppositeFace = face === 'front' ? 'rear' : 'front';
+      if (!nativeItemsByFace[oppositeFace].has(String(device.id))) {
+        addWidget(device, oppositeFace, 'back', true);
+      }
+    }
+  });
+
+  const snapElement = element => {
+    if (!element?.gridstackNode) return;
+    const width = Number.parseInt(element.dataset.rackWidth || '1', 10);
+    if (![1, 2, 3, 4].includes(width)) return;
+    const gridWidth = columns / width;
+    const node = element.gridstackNode;
+    const gridX = Math.max(0, Math.min(columns - gridWidth, Math.round(node.x / gridWidth) * gridWidth));
+    element.dataset.horizontalPosition = String(gridX / gridWidth + 1);
+    if (node.x !== gridX || node.w !== gridWidth) {
+      node.grid.update(element, {x: gridX, w: gridWidth});
+    }
+  };
+
+  const snapGrid = grid => grid.getGridItems().forEach(snapElement);
+  const attachSnapping = () => {
+    Object.values(gridElements).forEach(element => {
+      const grid = element.gridstack;
+      if (!grid) return;
+      grid.on('dragstop', (_event, item) => snapElement(item));
+      grid.on('dropped', (_event, _previous, current) => snapElement(current?.el));
+    });
+  };
+
+  document.addEventListener('click', event => {
+    const target = event.target instanceof Element ? event.target : event.target?.parentElement;
+    if (!target?.closest('#saveButton')) return;
+    Object.values(gridElements).forEach(element => {
+      if (element.gridstack) snapGrid(element.gridstack);
+    });
+  }, true);
+
+  document.addEventListener('DOMContentLoaded', attachSnapping, {once: true});
+})();

netbox_utilities/static/netbox_utilities/topology-rack-width.js

@@ -0,0 +1,387 @@
+(() => {
+  'use strict';
+
+  const placementSource = document.getElementById('netbox-utilities-topology-rack-width-data');
+  if (!placementSource) return;
+
+  let payload;
+  try {
+    payload = JSON.parse(placementSource.textContent);
+  } catch (error) {
+    console.error('NetBox Utilities could not read the Topology Views rack widths.', error);
+    return;
+  }
+  if (!Array.isArray(payload) && (payload?.schema_version !== 3 || payload?.complete !== true)) {
+    console.warn('NetBox Utilities received an incomplete Topology Views payload and kept the native layout.');
+    return;
+  }
+  if (!Array.isArray(payload) && payload?.status && payload.status !== 'ready') {
+    console.warn('NetBox Utilities is leaving Topology Views in its native layout.', payload.status);
+    return;
+  }
+  const placementData = Array.isArray(payload) ? payload : payload?.devices;
+  if (!Array.isArray(placementData)) {
+    console.error('NetBox Utilities received invalid Topology Views rack width data.');
+    return;
+  }
+
+  const normalizePath = value => {
+    try {
+      return new URL(value, document.baseURI).pathname.replace(/\/+$/, '/');
+    } catch (_) {
+      return '';
+    }
+  };
+
+  const normalizePlacement = value => {
+    const width = Number.parseInt(value?.width, 10);
+    const horizontalPosition = Number.parseInt(value?.horizontal_position, 10);
+    if (![2, 3, 4].includes(width) || horizontalPosition < 1 || horizontalPosition > width) return null;
+    return {
+      width,
+      horizontalPosition,
+      source: String(value.width_source || 'stored'),
+      leftPercent: Number.isFinite(Number(value.left_percent))
+        ? Number(value.left_percent)
+        : (horizontalPosition - 1) / width * 100,
+      widthPercent: Number.isFinite(Number(value.width_percent))
+        ? Number(value.width_percent)
+        : 100 / width,
+    };
+  };
+
+  const placementsByPath = new Map();
+  const placementsByDeviceId = new Map();
+  placementData.forEach(item => {
+    const placement = normalizePlacement(item);
+    if (!placement) return;
+    const path = normalizePath(item.url);
+    if (path) placementsByPath.set(path, placement);
+    placementsByDeviceId.set(String(item.device_id), placement);
+  });
+
+  const rackCards = Array.from(document.querySelectorAll('.rack-card[data-rack-id][data-rack-units]'));
+  const liveViewCompatible = rackCards.length > 0 && rackCards.every(card => {
+    if (!/^\d+$/.test(String(card.dataset.rackId)) || !Number.isFinite(Number(card.dataset.rackUnits))) {
+      return false;
+    }
+    return Array.from(card.querySelectorAll('.rack-device')).every(device => (
+      device.hasAttribute('href')
+      && ['front', 'rear'].includes(device.dataset.face)
+      && Number.isFinite(Number(device.dataset.position))
+      && Number.isFinite(Number(device.dataset.deviceHeight))
+      && typeof device.dataset.deviceColor === 'string'
+    ));
+  });
+  if (!rackCards.length && !placementData.length) return;
+  if (!liveViewCompatible) {
+    console.warn('NetBox Utilities left Topology Views unchanged because its rack DOM is not compatible.');
+    return;
+  }
+
+  const placementForElement = element => {
+    const path = normalizePath(element.getAttribute('href'));
+    if (placementsByPath.has(path)) return placementsByPath.get(path);
+    const deviceId = path.match(/\/devices\/(\d+)\/?$/)?.[1];
+    return deviceId ? placementsByDeviceId.get(deviceId) : null;
+  };
+
+  document.querySelectorAll('.rack-device').forEach(device => {
+    const placement = placementForElement(device);
+    if (!placement) return;
+    device.classList.add('netbox-utilities-partial-width');
+    device.dataset.rackWidth = String(placement.width);
+    device.dataset.horizontalPosition = String(placement.horizontalPosition);
+    device.dataset.rackWidthSource = placement.source;
+    device.style.setProperty('--netbox-utilities-rack-device-left', `${placement.leftPercent}%`);
+    device.style.setProperty('--netbox-utilities-rack-device-width', `${placement.widthPercent}%`);
+  });
+
+  const rackDataSource = document.getElementById('rack-export-data');
+  if (!rackDataSource) return;
+
+  let rackData;
+  try {
+    rackData = JSON.parse(rackDataSource.textContent);
+  } catch (error) {
+    console.error('NetBox Utilities could not read the Topology Views rack export data.', error);
+    return;
+  }
+
+  const rackExportCompatible = Array.isArray(rackData) && rackData.length > 0 && rackData.every(rack => {
+    if (!rack || !/^\d+$/.test(String(rack.id)) || !Array.isArray(rack.devices)) return false;
+    if (!Number.isFinite(Number(rack.u_height)) || !Number.isFinite(Number(rack.starting_unit))) return false;
+    const card = document.querySelector(`.rack-card[data-rack-id="${rack.id}"]`);
+    if (!card || !Number.isFinite(Number(card.dataset.rackUnits))) return false;
+    return true;
+  });
+  if (!rackExportCompatible) {
+    console.warn('NetBox Utilities left Topology Views exports unchanged because their schema is not compatible.');
+    return;
+  }
+
+  const xmlEscape = value => String(value ?? '').replace(/[&<>"']/g, character => ({
+    '&': '&amp;',
+    '<': '&lt;',
+    '>': '&gt;',
+    '"': '&quot;',
+    "'": '&apos;',
+  })[character]);
+  const safeName = value => String(value || 'export')
+    .replace(/[^a-z0-9._-]+/gi, '-')
+    .replace(/^-|-$/g, '');
+  const numberOr = (value, fallback) => {
+    const number = Number.parseFloat(value);
+    return Number.isFinite(number) ? number : fallback;
+  };
+
+  const activeNetBoxTheme = () => {
+    for (const element of [document.body, document.documentElement]) {
+      const match = getComputedStyle(element).backgroundColor.match(/[\d.]+/g);
+      if (match && match.length >= 3 && (match.length < 4 || Number(match[3]) > 0)) {
+        const [red, green, blue] = match.map(Number);
+        return (.2126 * red + .7152 * green + .0722 * blue) < 140 ? 'dark' : 'light';
+      }
+    }
+    return document.body.dataset.bsTheme || document.documentElement.dataset.bsTheme || 'light';
+  };
+
+  const exportPalette = () => activeNetBoxTheme() === 'dark' ? {
+    frame: '#52606d',
+    grid: '#667382',
+    heading: '#8fc8ff',
+    muted: '#a9b7c6',
+    deviceFill: '#162e45',
+    deviceText: '#ffffff',
+    deviceSubtext: '#cad5df',
+  } : {
+    frame: '#718096',
+    grid: '#8b99a8',
+    heading: '#0b69b7',
+    muted: '#52606d',
+    deviceFill: '#eef6ff',
+    deviceText: '#132238',
+    deviceSubtext: '#52606d',
+  };
+
+  const exportPlacement = device => {
+    const width = Number.parseInt(device.dataset.rackWidth || '1', 10);
+    const horizontalPosition = Number.parseInt(device.dataset.horizontalPosition || '1', 10);
+    if (![1, 2, 3, 4].includes(width) || horizontalPosition < 1 || horizontalPosition > width) {
+      return {width: 1, horizontalPosition: 1};
+    }
+    return {width, horizontalPosition};
+  };
+
+  const renderedRackData = racks => racks.map(rack => {
+    const card = document.querySelector(`.rack-card[data-rack-id="${rack.id}"]`);
+    if (!card) return rack;
+    const rackUnits = numberOr(card.dataset.rackUnits, numberOr(rack.u_height, 1));
+    const devices = Array.from(card.querySelectorAll('.rack-device')).map(device => {
+      const placement = exportPlacement(device);
+      return {
+        name: device.dataset.deviceName || device.querySelector('span')?.textContent || 'Gerät',
+        type: device.dataset.deviceType || '',
+        position: numberOr(device.dataset.position, numberOr(rack.starting_unit, 1)),
+        height: Math.max(numberOr(device.dataset.deviceHeight, 100 / rackUnits), 1),
+        face: device.dataset.face === 'rear' ? 'rear' : 'front',
+        color: device.dataset.deviceColor || '#1685fc',
+        width: placement.width,
+        horizontalPosition: placement.horizontalPosition,
+      };
+    });
+    return {...rack, devices};
+  });
+
+  const horizontalGeometry = (faceX, faceWidth, device) => {
+    const width = [1, 2, 3, 4].includes(device.width) ? device.width : 1;
+    const horizontalPosition = device.horizontalPosition >= 1 && device.horizontalPosition <= width
+      ? device.horizontalPosition
+      : 1;
+    const slotWidth = faceWidth / width;
+    return {
+      x: faceX + (horizontalPosition - 1) * slotWidth + 3,
+      width: Math.max(slotWidth - 6, 1),
+    };
+  };
+
+  const svgDocument = (width, height, content) =>
+    `<svg xmlns="http://www.w3.org/2000/svg" width="${width}" height="${height}" viewBox="0 0 ${width} ${height}">${content}</svg>`;
+  const drawioDocument = cells =>
+    `<mxfile host="app.diagrams.net" type="device"><diagram name="Rack export"><mxGraphModel page="0" background="none" grid="1" guides="1" connect="1"><root><mxCell id="0"/><mxCell id="1" parent="0"/>${cells}</root></mxGraphModel></diagram></mxfile>`;
+
+  const buildRackDrawio = racks => {
+    const palette = exportPalette();
+    const unit = 22;
+    const faceWidth = 250;
+    const labelWidth = 28;
+    const faceGap = 28;
+    const rackGap = 44;
+    const header = 55;
+    const rackWidth = labelWidth + faceWidth * 2 + faceGap;
+    let cells = '';
+    let cellId = 2;
+    const vertex = (value, style, x, y, width, height) => {
+      cells += `<mxCell id="${cellId++}" value="${xmlEscape(value)}" style="${style}" vertex="1" parent="1"><mxGeometry x="${x}" y="${y}" width="${width}" height="${height}" as="geometry"/></mxCell>`;
+    };
+
+    racks.forEach((rack, rackIndex) => {
+      const rackUnits = numberOr(rack.u_height, 1);
+      const baseX = 10 + rackIndex * (rackWidth + rackGap);
+      const rackHeight = rackUnits * unit;
+      const startingUnit = numberOr(rack.starting_unit, 1);
+      vertex(rack.name, `text;html=1;strokeColor=none;fillColor=none;align=left;verticalAlign=middle;fontSize=16;fontStyle=1;fontColor=${palette.heading};`, baseX, 0, rackWidth, 25);
+      vertex(`${rack.site}${rack.location ? ` · ${rack.location}` : ''} · ${rackUnits}U`, `text;html=1;strokeColor=none;fillColor=none;align=left;fontSize=10;fontColor=${palette.muted};`, baseX, 24, rackWidth, 20);
+      ['front', 'rear'].forEach((face, faceIndex) => {
+        const faceX = baseX + labelWidth + faceIndex * (faceWidth + faceGap);
+        vertex(face === 'front' ? 'VORDERSEITE' : 'RÜCKSEITE', `text;html=1;strokeColor=none;fillColor=none;align=center;fontSize=10;fontColor=${palette.muted};`, faceX, 38, faceWidth, 17);
+        vertex('', `rounded=0;html=1;fillColor=none;strokeColor=${palette.frame};strokeWidth=4;`, faceX, header, faceWidth, rackHeight);
+        for (let row = 0; row < rackUnits; row += 1) {
+          const y = header + row * unit;
+          const unitLabel = rack.desc_units ? startingUnit + row : startingUnit + rackUnits - 1 - row;
+          if (faceIndex === 0) {
+            vertex(String(unitLabel), `text;html=1;strokeColor=none;fillColor=none;align=right;fontSize=8;fontColor=${palette.muted};`, faceX - labelWidth, y, labelWidth - 4, unit);
+          }
+        }
+        rack.devices.filter(device => device.face === face).forEach(device => {
+          const positionOffset = device.position - startingUnit;
+          const y = rack.desc_units
+            ? header + positionOffset * unit
+            : header + rackHeight - (positionOffset + device.height) * unit;
+          const height = Math.max(device.height * unit, 4);
+          const geometry = horizontalGeometry(faceX, faceWidth, device);
+          const value = height >= 31
+            ? `${device.name}<br><font style="font-size:9px">U${device.position} · ${device.type}</font>`
+            : device.name;
+          vertex(value, `rounded=1;html=1;whiteSpace=wrap;overflow=hidden;align=left;verticalAlign=top;spacingLeft=5;spacingTop=2;fillColor=${palette.deviceFill};strokeColor=${device.color};strokeWidth=2;fontColor=${palette.deviceText};fontSize=11;`, geometry.x, y + 1, geometry.width, height - 2);
+        });
+      });
+    });
+    return drawioDocument(cells);
+  };
+
+  const buildRackSvg = racks => {
+    const palette = exportPalette();
+    const unit = 22;
+    const faceWidth = 250;
+    const labelWidth = 28;
+    const faceGap = 28;
+    const rackGap = 44;
+    const header = 55;
+    const rackWidth = labelWidth + faceWidth * 2 + faceGap;
+    const maxUnits = Math.max(...racks.map(rack => numberOr(rack.u_height, 1)), 1);
+    const width = racks.length * rackWidth + Math.max(0, racks.length - 1) * rackGap + 20;
+    const height = header + maxUnits * unit + 25;
+    let definitions = '';
+    let content = '';
+
+    racks.forEach((rack, rackIndex) => {
+      const rackUnits = numberOr(rack.u_height, 1);
+      const baseX = 10 + rackIndex * (rackWidth + rackGap);
+      const rackHeight = rackUnits * unit;
+      const startingUnit = numberOr(rack.starting_unit, 1);
+      content += `<text x="${baseX}" y="20" fill="${palette.heading}" font-family="sans-serif" font-size="16" font-weight="700">${xmlEscape(rack.name)}</text>`;
+      content += `<text x="${baseX}" y="39" fill="${palette.muted}" font-family="sans-serif" font-size="11">${xmlEscape(rack.site)}${rack.location ? ` · ${xmlEscape(rack.location)}` : ''} · ${rackUnits}U</text>`;
+      ['front', 'rear'].forEach((face, faceIndex) => {
+        const faceX = baseX + labelWidth + faceIndex * (faceWidth + faceGap);
+        content += `<text x="${faceX + faceWidth / 2}" y="51" text-anchor="middle" fill="${palette.muted}" font-family="sans-serif" font-size="10">${face === 'front' ? 'VORDERSEITE' : 'RÜCKSEITE'}</text>`;
+        content += `<rect x="${faceX}" y="${header}" width="${faceWidth}" height="${rackHeight}" fill="none" stroke="${palette.frame}" stroke-width="4"/>`;
+        for (let row = 0; row < rackUnits; row += 1) {
+          const y = header + row * unit;
+          const unitLabel = rack.desc_units ? startingUnit + row : startingUnit + rackUnits - 1 - row;
+          content += `<line x1="${faceX}" y1="${y}" x2="${faceX + faceWidth}" y2="${y}" stroke="${palette.grid}" stroke-opacity=".35"/>`;
+          if (faceIndex === 0) {
+            content += `<text x="${faceX - 6}" y="${y + 15}" text-anchor="end" fill="${palette.muted}" font-family="sans-serif" font-size="9">${unitLabel}</text>`;
+          }
+        }
+        rack.devices.filter(device => device.face === face).forEach((device, deviceIndex) => {
+          const positionOffset = device.position - startingUnit;
+          const y = rack.desc_units
+            ? header + positionOffset * unit
+            : header + rackHeight - (positionOffset + device.height) * unit;
+          const deviceHeight = Math.max(device.height * unit, 4);
+          const geometry = horizontalGeometry(faceX, faceWidth, device);
+          const clipId = `netbox-utilities-rack-${rackIndex}-${faceIndex}-${deviceIndex}`;
+          definitions += `<clipPath id="${clipId}"><rect x="${geometry.x}" y="${y + 1}" width="${geometry.width}" height="${deviceHeight - 2}"/></clipPath>`;
+          content += `<g clip-path="url(#${clipId})">`;
+          content += `<rect x="${geometry.x}" y="${y + 1}" width="${geometry.width}" height="${deviceHeight - 2}" rx="3" fill="${palette.deviceFill}" stroke="${xmlEscape(device.color)}" stroke-width="2"/>`;
+          if (deviceHeight >= 13) {
+            content += `<text x="${geometry.x + 6}" y="${y + Math.min(15, deviceHeight - 4)}" fill="${palette.deviceText}" font-family="sans-serif" font-size="11" font-weight="600">${xmlEscape(device.name)}</text>`;
+          }
+          if (deviceHeight >= 31) {
+            content += `<text x="${geometry.x + 6}" y="${y + 28}" fill="${palette.deviceSubtext}" font-family="sans-serif" font-size="9">U${device.position} · ${xmlEscape(device.type)}</text>`;
+          }
+          content += '</g>';
+        });
+      });
+    });
+
+    const svg = svgDocument(width, height, `<defs>${definitions}</defs>${content}`);
+    return {svg, drawio: buildRackDrawio(racks), width, height};
+  };
+
+  const downloadBlob = (blob, filename) => {
+    const link = document.createElement('a');
+    link.href = URL.createObjectURL(blob);
+    link.download = filename;
+    link.click();
+    setTimeout(() => URL.revokeObjectURL(link.href), 1000);
+  };
+
+  const exportGraphic = (graphic, format, filename) => {
+    if (format === 'svg') {
+      downloadBlob(new Blob([graphic.svg], {type: 'image/svg+xml'}), `${filename}.svg`);
+      return;
+    }
+    if (format === 'drawio') {
+      downloadBlob(new Blob([graphic.drawio], {type: 'application/xml'}), `${filename}.drawio`);
+      return;
+    }
+
+    const image = new Image();
+    const url = URL.createObjectURL(new Blob([graphic.svg], {type: 'image/svg+xml'}));
+    image.onload = () => {
+      const scale = 2;
+      const canvas = document.createElement('canvas');
+      canvas.width = graphic.width * scale;
+      canvas.height = graphic.height * scale;
+      const context = canvas.getContext('2d');
+      context.clearRect(0, 0, canvas.width, canvas.height);
+      context.scale(scale, scale);
+      context.drawImage(image, 0, 0);
+      canvas.toBlob(blob => downloadBlob(blob, `${filename}.png`), 'image/png');
+      URL.revokeObjectURL(url);
+    };
+    image.onerror = () => URL.revokeObjectURL(url);
+    image.src = url;
+  };
+
+  const selectedRacks = button => button.dataset.scope === 'all'
+    ? rackData
+    : rackData.filter(rack => String(rack.id) === button.dataset.scope);
+  const containsPartialWidthDevice = racks => racks.some(rack =>
+    document.querySelector(`.rack-card[data-rack-id="${rack.id}"] .netbox-utilities-partial-width`));
+
+  document.addEventListener('click', event => {
+    const target = event.target instanceof Element ? event.target : event.target?.parentElement;
+    const button = target?.closest('.rack-export');
+    if (!button) return;
+
+    const selection = selectedRacks(button);
+    if (!selection.length || !containsPartialWidthDevice(selection)) return;
+
+    try {
+      const racks = renderedRackData(selection);
+      const graphic = buildRackSvg(racks);
+      const filename = button.dataset.scope === 'all'
+        ? 'racks-gesamt'
+        : `rack-${safeName(racks[0]?.name)}`;
+      exportGraphic(graphic, button.dataset.format, filename);
+      event.preventDefault();
+      event.stopImmediatePropagation();
+    } catch (error) {
+      // Let Topology Views' original click handler provide its normal export fallback.
+      console.error('NetBox Utilities could not create the width-aware rack export.', error);
+    }
+  }, true);
+})();

netbox_utilities/template_content.py

@@ -5,7 +5,12 @@ from netbox.plugins import PluginTemplateExtension
 from tenancy.models import Tenant, TenantGroup
 
 from . import __version__
-from .models import NavigationPreference
+from .models import (
+    CableVLANAssignment,
+    DeviceRackPlacement,
+    NavigationPreference,
+    WirelessLinkVLANAssignment,
+)
 from .navigation_helpers import (
     SIDEBAR_WIDTH_DEFAULT,
     SIDEBAR_WIDTH_MAX,
@@ -14,7 +19,7 @@ from .navigation_helpers import (
     normalize_preferences,
     normalize_sidebar_width,
 )
-from .runtime import navigation_customization_enabled, tenant_filter_enabled
+from .runtime import connection_vlans_enabled, navigation_customization_enabled, tenant_filter_enabled
 
 
 class UtilitiesGlobalContent(PluginTemplateExtension):
@@ -99,5 +104,47 @@ class DeviceUtilitiesContent(PluginTemplateExtension):
             return ""
         return self.render("netbox_utilities/device_bulk_module_button.html")
 
+    def right_page(self):
+        placement = DeviceRackPlacement.objects.filter(device=self.context["object"]).first()
+        if placement is None:
+            return ""
+        return self.render(
+            "netbox_utilities/device_rack_width_panel.html",
+            {
+                "rack_width": f"1/{placement.width}",
+                "horizontal_position": placement.horizontal_position,
+            },
+        )
 
-template_extensions = [UtilitiesGlobalContent, DeviceUtilitiesContent]
+
+class ConnectionVLANContent(PluginTemplateExtension):
+    models = ["dcim.cable", "wireless.wirelesslink"]
+
+    def right_page(self):
+        if not connection_vlans_enabled():
+            return ""
+
+        connection = self.context["object"]
+        if connection._meta.label_lower == "dcim.cable":
+            assignment_model = CableVLANAssignment
+            lookup = {"cable": connection}
+        else:
+            assignment_model = WirelessLinkVLANAssignment
+            lookup = {"wireless_link": connection}
+
+        assignment = assignment_model.objects.filter(**lookup).first()
+        if assignment is None:
+            return ""
+
+        from ipam.models import VLAN
+
+        visible_vlans = VLAN.objects.restrict(self.context["request"].user, "view").filter(
+            pk__in=assignment.vlans.values("pk")
+        )
+        return self.render(
+            "netbox_utilities/connection_vlans_panel.html",
+            {"connection_vlans": visible_vlans},
+        )
+
+
+template_extensions = [UtilitiesGlobalContent, DeviceUtilitiesContent, ConnectionVLANContent]

netbox_utilities/templates/netbox_utilities/cable_edit.html

@@ -0,0 +1,5 @@
+{% extends 'dcim/cable_edit.html' %}
+
+{% block form %}
+  {% include 'netbox_utilities/cable_edit_form.html' %}
+{% endblock %}

netbox_utilities/templates/netbox_utilities/cable_edit_form.html

@@ -0,0 +1,123 @@
+{% load static %}
+{% load helpers %}
+{% load form_helpers %}
+{% load i18n %}
+
+{% for field in form.hidden_fields %}
+  {{ field }}
+{% endfor %}
+
+{# A side termination #}
+<div class="field-group mb-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "A Side" %}</h2>
+  </div>
+  {% render_field form.a_terminations_type %}
+  {% if 'termination_a_device' in form.fields %}
+    {% render_field form.termination_a_device %}
+  {% endif %}
+  {% if 'termination_a_powerpanel' in form.fields %}
+    {% render_field form.termination_a_powerpanel %}
+  {% endif %}
+  {% if 'termination_a_circuit' in form.fields %}
+    {% render_field form.termination_a_circuit %}
+  {% endif %}
+  {% if 'a_terminations' in form.fields %}
+    {% render_field form.a_terminations %}
+  {% endif %}
+</div>
+
+{# B side termination and connection VLANs #}
+<div class="field-group mb-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "B Side" %}</h2>
+  </div>
+  {% render_field form.b_terminations_type %}
+  {% if 'termination_b_device' in form.fields %}
+    {% render_field form.termination_b_device %}
+  {% endif %}
+  {% if 'termination_b_powerpanel' in form.fields %}
+    {% render_field form.termination_b_powerpanel %}
+  {% endif %}
+  {% if 'termination_b_circuit' in form.fields %}
+    {% render_field form.termination_b_circuit %}
+  {% endif %}
+  {% if 'b_terminations' in form.fields %}
+    {% render_field form.b_terminations %}
+  {% endif %}
+  {% if form.utilities_vlan_group %}
+    {% render_field form.utilities_vlan_group %}
+  {% endif %}
+  {% if form.utilities_vlans %}
+    {% render_field form.utilities_vlans %}
+  {% endif %}
+</div>
+
+{# Cable attributes #}
+<div class="field-group mb-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Cable" %}</h2>
+  </div>
+  {% render_field form.status %}
+  {% render_field form.profile %}
+  {% render_field form.type %}
+  {% render_field form.bundle %}
+  {% render_field form.label %}
+  {% render_field form.description %}
+  {% render_field form.color %}
+  <div class="row mb-3{% if form.length.errors or form.length_unit.errors %} has-errors{% endif %}">
+    <label class="col-sm-3 col-form-label text-lg-end">{{ form.length.label }}</label>
+    <div class="col-md-5">
+      {% render_field_with_aria form.length %}
+      {% if form.length.errors %}
+        <div class="form-text text-danger" id="{{ form.length.auto_id }}_errors" role="alert">
+          {% for error in form.length.errors %}{{ error }}{% if not forloop.last %}<br />{% endif %}{% endfor %}
+        </div>
+      {% endif %}
+    </div>
+    <div class="col-md-4">
+      {% render_field_with_aria form.length_unit %}
+      {% if form.length_unit.errors %}
+        <div class="form-text text-danger" id="{{ form.length_unit.auto_id }}_errors" role="alert">
+          {% for error in form.length_unit.errors %}{{ error }}{% if not forloop.last %}<br />{% endif %}{% endfor %}
+        </div>
+      {% endif %}
+    </div>
+  </div>
+  {% render_field form.tags %}
+</div>
+
+<div class="field-group mb-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Tenancy" %}</h2>
+  </div>
+  {% render_field form.tenant_group %}
+  {% render_field form.tenant %}
+</div>
+
+<div class="field-group mb-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Ownership" %}</h2>
+  </div>
+  {% render_field form.owner_group %}
+  {% render_field form.owner %}
+</div>
+
+{% if form.custom_fields %}
+  <div class="field-group mb-5">
+    <div class="row">
+      <h2 class="col-9 offset-3">{% trans "Custom Fields" %}</h2>
+    </div>
+    {% render_custom_fields form %}
+  </div>
+{% endif %}
+
+<div class="field-group mb-5">
+  <h2 class="text-center">{% trans "Comments" %}</h2>
+  {% render_field form.comments %}
+</div>
+
+{# Meta fields #}
+<div class="bg-primary-subtle border border-primary rounded-1 pt-3 px-3 mb-3">
+  {% render_field form.changelog_message %}
+</div>

netbox_utilities/templates/netbox_utilities/connection_vlans_panel.html

@@ -0,0 +1,12 @@
+<div class="card">
+  <h2 class="card-header">VLANs der Verbindung</h2>
+  <div class="card-body">
+    {% if connection_vlans %}
+      {% for vlan in connection_vlans %}
+        <a href="{{ vlan.get_absolute_url }}" class="badge text-bg-primary me-1 mb-1">{{ vlan }}</a>
+      {% endfor %}
+    {% else %}
+      <span class="text-muted">Keine VLANs zugeordnet</span>
+    {% endif %}
+  </div>
+</div>

netbox_utilities/templates/netbox_utilities/device_edit.html

@@ -0,0 +1,5 @@
+{% extends 'dcim/device_edit.html' %}
+
+{% block form %}
+  {% include 'netbox_utilities/device_edit_form.html' %}
+{% endblock form %}

netbox_utilities/templates/netbox_utilities/device_edit_form.html

@@ -0,0 +1,130 @@
+{% load form_helpers %}
+{% load i18n %}
+
+{% for field in form.hidden_fields %}
+  {{ field }}
+{% endfor %}
+
+<div class="field-group my-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Device" %}</h2>
+  </div>
+  {% render_field form.name %}
+  {% render_field form.role %}
+  {% render_field form.description %}
+  {% render_field form.tags %}
+</div>
+
+<div class="field-group my-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Hardware" %}</h2>
+  </div>
+  {% render_field form.device_type %}
+  {% render_field form.airflow %}
+  {% render_field form.serial %}
+  {% render_field form.asset_tag %}
+</div>
+
+<div class="field-group my-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Location" %}</h2>
+  </div>
+  {% render_field form.site %}
+  {% render_field form.location %}
+  {% render_field form.rack %}
+
+  {% if object.device_type.is_child_device and object.parent_bay %}
+    <div class="row mb-3">
+      <label for="id_parent_device" class="col-sm-3 col-form-label">{% trans "Parent Device" %}</label>
+      <div class="col">
+        <input id="id_parent_device" class="form-control" value="{{ object.parent_bay.device }}" disabled />
+      </div>
+    </div>
+    <div class="row mb-3">
+      <label for="id_parent_bay" class="col-sm-3 col-form-label">{% trans "Parent Bay" %}</label>
+      <div class="col">
+        <div class="input-group">
+          <input id="id_parent_bay" class="form-control" value="{{ object.parent_bay.name }}" disabled />
+          <a href="{% url 'dcim:devicebay_depopulate' pk=object.parent_bay.pk %}" title="{% trans "Remove" %}" aria-label="{% trans "Remove" %}" class="btn btn-danger d-inline-flex align-items-center">
+            <i class="mdi mdi-close-thick" aria-hidden="true"></i>&nbsp;{% trans "Remove" %}
+          </a>
+        </div>
+      </div>
+    </div>
+  {% else %}
+    {% render_field form.face %}
+    {% render_field form.position %}
+    {% render_field form.utilities_rack_width %}
+    {% render_field form.utilities_horizontal_position %}
+    {% render_field form.latitude %}
+    {% render_field form.longitude %}
+  {% endif %}
+</div>
+
+<div class="field-group my-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Management" %}</h2>
+  </div>
+  {% render_field form.status %}
+  {% render_field form.platform %}
+  {% render_field form.config_template %}
+  {% if object.pk %}
+    {% render_field form.primary_ip4 %}
+    {% render_field form.primary_ip6 %}
+    {% render_field form.oob_ip %}
+  {% endif %}
+</div>
+
+<div class="field-group my-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Virtualization" %}</h2>
+  </div>
+  {% render_field form.cluster %}
+</div>
+
+<div class="field-group my-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Tenancy" %}</h2>
+  </div>
+  {% render_field form.tenant_group %}
+  {% render_field form.tenant %}
+</div>
+
+<div class="field-group my-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Virtual Chassis" %}</h2>
+  </div>
+  {% render_field form.virtual_chassis %}
+  {% render_field form.vc_position %}
+  {% render_field form.vc_priority %}
+</div>
+
+<div class="field-group mb-5">
+  <div class="row">
+    <h2 class="col-9 offset-3">{% trans "Ownership" %}</h2>
+  </div>
+  {% render_field form.owner_group %}
+  {% render_field form.owner %}
+</div>
+
+{% if form.custom_fields %}
+  <div class="field-group my-5">
+    <div class="row">
+      <h2 class="col-9 offset-3">{% trans "Custom Fields" %}</h2>
+    </div>
+    {% render_custom_fields form %}
+  </div>
+{% endif %}
+
+<div class="field-group my-5">
+  <h2 class="text-center">{% trans "Local Config Context Data" %}</h2>
+  {% render_field form.local_context_data %}
+</div>
+
+<div class="field-group mb-5">
+  {% render_field form.comments %}
+</div>
+
+<div class="bg-primary-subtle border border-primary rounded-1 pt-3 px-3 mb-3">
+  {% render_field form.changelog_message %}
+</div>

netbox_utilities/templates/netbox_utilities/device_rack_width_panel.html

@@ -0,0 +1,13 @@
+<div class="card">
+  <h2 class="card-header">Rackbreite</h2>
+  <table class="table table-hover attr-table">
+    <tr>
+      <th scope="row">Breite</th>
+      <td>{{ rack_width }} der Rackbreite</td>
+    </tr>
+    <tr>
+      <th scope="row">Position von links</th>
+      <td>{{ horizontal_position }}</td>
+    </tr>
+  </table>
+</div>

netbox_utilities/templates/netbox_utilities/reorder_rack.html

@@ -0,0 +1,58 @@
+{% extends "netbox_reorder_rack/rack.html" %}
+{% load perms %}
+{% load rack %}
+{% load i18n %}
+{% load static %}
+
+{% block head %}
+  {{ block.super }}
+  {{ reorder_rack_width_data|json_script:"netbox-utilities-reorder-rack-width-data" }}
+  <script src="{% static 'netbox_utilities/reorder-rack-width.js' %}?v={{ asset_version }}" defer></script>
+{% endblock %}
+
+{% block content %}
+  <div class="row">
+    <div class="d-flex justify-content-end btn-list mb-2">
+      <select class="btn btn-outline-secondary no-ts rack-view" id="view-selector">
+        <option value="images-and-labels"{% if images and labels %} selected{% endif %}>{% trans "Images and Labels" %}</option>
+        <option value="images-only"{% if images and not labels %} selected{% endif %}>{% trans "Images only" %}</option>
+        <option value="labels-only"{% if labels and not images %} selected{% endif %}>{% trans "Labels only" %}</option>
+      </select>
+      <button class="btn btn-success" id="saveButton" disabled>Save</button>
+    </div>
+  </div>
+  <div class="container mt-2">
+    <div class="row">
+      <div class="col-lg-4 col-md-6 col-sm-12 text-center">
+        <h4>Front</h4>
+        {% include "netbox_utilities/reorder_rack_grid.html" with face="front" grid_id=0 %}
+      </div>
+      <div class="col-lg-4 col-md-6 col-sm-12 text-center">
+        <h4>Back</h4>
+        {% include "netbox_utilities/reorder_rack_grid.html" with face="rear" grid_id=1 %}
+      </div>
+      <div class="col-lg-4 col-md-6 col-sm-12 text-center">
+        <h4>Non-Racked Devices</h4>
+        <div class="d-flex justify-content-center">
+          <div class="grid-stack rack netbox-utilities-reorder-grid" id="grid-other" gs-column="12" gs-max-row="150"
+               gs-min-row="{{ object.u_height|mul:2 }}" data-grid-id="2">
+            {% for device in non_racked %}
+              <div class="grid-stack-item" gs-w="12" gs-h="{{ device.device_type.u_height|mul:2 }}"
+                   gs-x="0" gs-id="{{ device.pk }}" data-item-face="none"
+                   data-item-color="{{ device.role.color|default:'1685fc' }}"
+                   data-item-text-color="{% if device.role.color %}{{ device.role.color|text_color }}{% else %}000000{% endif %}"
+                   data-full-depth="{{ device.device_type.is_full_depth }}"
+                   gs-locked="{% if not request.user|can_change:device %}true{% else %}false{% endif %}"
+                   gs-no-move="{% if not request.user|can_change:device %}true{% else %}false{% endif %}">
+                <div class="grid-stack-item-content"
+                     style="{% if images and device.device_type.front_image %}background-image: url('{{ device.device_type.front_image.url }}'); background-size: {{ unit_width }}px;{% else %}background-color: #{{ device.role.color|default:'1685fc' }};{% endif %} color: #{% if device.role.color %}{{ device.role.color|text_color }}{% else %}000000{% endif %}">
+                  {% if images and device.device_type.front_image %}{% if labels %}{{ device.name|default:device.device_type }}{% endif %}{% else %}{{ device.name|default:device.device_type }}{% endif %}
+                </div>
+              </div>
+            {% endfor %}
+          </div>
+        </div>
+      </div>
+    </div>
+  </div>
+{% endblock %}

netbox_utilities/templates/netbox_utilities/reorder_rack_grid.html

@@ -0,0 +1,40 @@
+{% load rack %}
+<div class="d-flex justify-content-center">
+  <div class="rack_front d-flex">
+    <ul class="unit_numbers">
+      {% for unit in object.units %}
+        {% if unit|rack_unit %}<li>{{ unit|rack_unit_to_int }}</li>{% else %}<li></li>{% endif %}
+      {% endfor %}
+    </ul>
+    <div class="grid-stack rack netbox-utilities-reorder-grid" id="grid-{{ face }}" gs-column="12"
+         gs-max-row="{{ object.u_height|mul:2 }}" gs-min-row="{{ object.u_height|mul:2 }}"
+         data-grid-id="{{ grid_id }}">
+      {% for device in reorder_devices %}
+        {% if device.face == face or device.full_depth %}
+          <div class="grid-stack-item" gs-w="{{ device.grid_width }}" gs-h="{{ device.grid_height }}"
+               gs-x="{{ device.grid_x }}" gs-y="{{ device.grid_y }}" gs-id="{{ device.id }}"
+               gs-locked="{% if device.locked %}true{% else %}false{% endif %}"
+               gs-no-move="{% if device.locked %}true{% else %}false{% endif %}"
+               data-item-color="{{ device.color }}" data-item-text-color="{{ device.text_color }}"
+               data-full-depth="{% if device.full_depth %}True{% else %}False{% endif %}"
+               data-item-face="{% if device.face == face %}{{ face }}{% else %}back{% endif %}"
+               data-rack-width="{{ device.width }}"
+               data-horizontal-position="{{ device.horizontal_position }}">
+            {% if device.face == face %}
+              <div class="grid-stack-item-content"
+                   style="{% if images and device.front_image %}background-image: url('{{ device.front_image }}'); background-size: {{ unit_width }}px; color: #{{ device.text_color }}{% else %}background-color: #{{ device.color }}; color: #{{ device.text_color }}{% endif %}">
+                {% if images and device.front_image %}{% if labels %}{{ device.label }}{% endif %}{% else %}{{ device.label }}{% endif %}
+              </div>
+            {% else %}
+              <div class="grid-stack-item-content device_rear"
+                   style="{% if images and device.rear_image %}background-image: url('{{ device.rear_image }}'); background-size: {{ unit_width }}px; color: #{{ device.text_color }}{% else %}color: #000000{% endif %}">
+                {% if images and device.rear_image %}{% if labels %}{{ device.label }}{% endif %}{% else %}{{ device.label }}{% endif %}
+              </div>
+            {% endif %}
+          </div>
+        {% endif %}
+      {% endfor %}
+    </div>
+    <ul class="indexes"></ul>
+  </div>
+</div>

netbox_utilities/tenant_autofill.py

@@ -25,16 +25,20 @@ def tenant_id_from_object(obj, depth=0):
     if isinstance(obj, Tenant):
         return obj.pk
 
-    field_names = {field.name for field in obj._meta.get_fields()}
-    if "tenant" in field_names and getattr(obj, "tenant_id", None):
+    meta = getattr(obj, "_meta", None)
+    if meta is None or not hasattr(meta, "get_fields"):
+        return None
+    fields = {field.name: field for field in meta.get_fields()}
+    if "tenant" in fields and getattr(obj, "tenant_id", None):
         return obj.tenant_id
 
     for relation in PARENT_RELATIONS:
-        if relation not in field_names:
+        field = fields.get(relation)
+        if field is None or getattr(field, "one_to_many", False) or getattr(field, "many_to_many", False):
             continue
         try:
             parent = getattr(obj, relation, None)
-        except (ObjectDoesNotExist, ValueError):
+        except (AttributeError, ObjectDoesNotExist, ValueError):
             continue
         if tenant_id := tenant_id_from_object(parent, depth + 1):
             return tenant_id
@@ -76,11 +80,7 @@ def _related_objects(form, field_name):
 
 def _is_cable(instance):
     meta = getattr(instance, "_meta", None)
-    return bool(
-        meta
-        and getattr(meta, "app_label", None) == "dcim"
-        and getattr(meta, "model_name", None) == "cable"
-    )
+    return bool(meta and getattr(meta, "app_label", None) == "dcim" and getattr(meta, "model_name", None) == "cable")
 
 
 def _instance_cable_terminations(instance):

netbox_utilities/tests/test_connection_vlans.py

@@ -0,0 +1,145 @@
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+from django import forms
+from django.forms.utils import ErrorDict
+from django.template.loader import get_template
+from django.test import SimpleTestCase
+
+from netbox_utilities.connection_vlans import (
+    FORM_FIELD,
+    GROUP_FILTER_FIELD,
+    _build_connection_vlan_form,
+    include_connection_vlans_in_fieldsets,
+)
+from netbox_utilities.models import CableVLANAssignment, WirelessLinkVLANAssignment
+
+
+class ConnectionVLANTest(SimpleTestCase):
+    def test_cable_vlan_field_is_rendered_below_b_side(self):
+        self.assertIsNotNone(get_template("netbox_utilities/cable_edit_form.html"))
+        template_path = Path(__file__).parents[1] / "templates" / "netbox_utilities" / "cable_edit_form.html"
+        template = template_path.read_text(encoding="utf-8")
+
+        b_side = template.index('{% trans "B Side" %}')
+        group_filter = template.index("{% render_field form.utilities_vlan_group %}")
+        vlan_field = template.index("{% render_field form.utilities_vlans %}")
+        cable_section = template.index('{% trans "Cable" %}')
+
+        self.assertLess(b_side, group_filter)
+        self.assertLess(group_filter, vlan_field)
+        self.assertLess(vlan_field, cable_section)
+        self.assertEqual(template.count("{% render_field form.utilities_vlan_group %}"), 1)
+        self.assertEqual(template.count("{% render_field form.utilities_vlans %}"), 1)
+
+    def test_assignment_models_are_tied_to_their_connection_and_vlans(self):
+        self.assertEqual(
+            CableVLANAssignment._meta.get_field("cable").remote_field.model._meta.label_lower, "dcim.cable"
+        )
+        self.assertEqual(
+            WirelessLinkVLANAssignment._meta.get_field("wireless_link").remote_field.model._meta.label_lower,
+            "wireless.wirelesslink",
+        )
+        self.assertEqual(CableVLANAssignment._meta.get_field("vlans").remote_field.model._meta.label_lower, "ipam.vlan")
+        self.assertEqual(
+            WirelessLinkVLANAssignment._meta.get_field("vlans").remote_field.model._meta.label_lower,
+            "ipam.vlan",
+        )
+
+    def test_connection_vlan_field_is_inserted_into_link_fieldset(self):
+        from utilities.forms.rendering import FieldSet
+
+        original = (FieldSet("status", "description", "tags", name="Link"),)
+
+        extended = include_connection_vlans_in_fieldsets(original)
+
+        self.assertEqual(
+            extended[0].items,
+            ("status", "description", GROUP_FILTER_FIELD, FORM_FIELD, "tags"),
+        )
+        self.assertEqual(original[0].items, ("status", "description", "tags"))
+
+    def test_resolved_edit_views_expose_connection_vlan_field(self):
+        import dcim.forms
+        from dcim.models import Interface
+        from dcim.views import CableEditView
+        from wireless.views import WirelessLinkEditView
+
+        cable_form = dcim.forms.get_cable_form(Interface, Interface)
+
+        self.assertIn(GROUP_FILTER_FIELD, cable_form.base_fields)
+        self.assertIn(FORM_FIELD, cable_form.base_fields)
+        self.assertEqual(cable_form.base_fields[FORM_FIELD].query_params, {"group_id": f"${GROUP_FILTER_FIELD}"})
+        self.assertEqual(CableEditView.template_name, "netbox_utilities/cable_edit.html")
+        self.assertEqual(CableEditView.htmx_template_name, "netbox_utilities/cable_edit_form.html")
+        self.assertIn(GROUP_FILTER_FIELD, WirelessLinkEditView.form.base_fields)
+        self.assertIn(FORM_FIELD, WirelessLinkEditView.form.base_fields)
+        self.assertEqual(
+            WirelessLinkEditView.form.base_fields[FORM_FIELD].query_params,
+            {"group_id": f"${GROUP_FILTER_FIELD}"},
+        )
+
+    @patch("netbox_utilities.connection_vlans.CableVLANAssignment.objects")
+    def test_form_loads_and_saves_multiple_vlans(self, assignment_objects):
+        from dcim.models import Cable
+        from utilities.forms.rendering import FieldSet
+
+        class BareCableForm(forms.ModelForm):
+            fieldsets = (FieldSet("description", name="Cable"),)
+
+            class Meta:
+                model = Cable
+                fields = ()
+
+        vlan_a = SimpleNamespace(pk=10, group_id=5)
+        vlan_b = SimpleNamespace(pk=20, group_id=5)
+        assignment = MagicMock()
+        assignment.vlans.all.return_value = [vlan_a, vlan_b]
+        assignment_objects.filter.return_value.prefetch_related.return_value.first.return_value = assignment
+        assignment_objects.get_or_create.return_value = (assignment, False)
+        cable = Cable(pk=7)
+        form_class = _build_connection_vlan_form(BareCableForm, CableVLANAssignment, "cable")
+        with patch(
+            "netbox_utilities.runtime._get_database_settings",
+            return_value={"tenant_required": True},
+        ):
+            form = form_class(instance=cable)
+
+        self.assertEqual(form.initial[FORM_FIELD], [vlan_a, vlan_b])
+        self.assertEqual(form.initial[GROUP_FILTER_FIELD], 5)
+
+        form._errors = ErrorDict()
+        form.cleaned_data = {FORM_FIELD: [vlan_a, vlan_b]}
+        with patch.object(Cable, "save"):
+            self.assertIs(form.save(), cable)
+
+        assignment_objects.get_or_create.assert_called_once_with(cable=cable)
+        assignment.vlans.set.assert_called_once_with([vlan_a, vlan_b])
+
+    @patch("netbox_utilities.connection_vlans.CableVLANAssignment.objects")
+    def test_empty_form_selection_removes_assignment(self, assignment_objects):
+        from dcim.models import Cable
+
+        class BareCableForm(forms.ModelForm):
+            fieldsets = ()
+
+            class Meta:
+                model = Cable
+                fields = ()
+
+        cable = Cable(pk=8)
+        form_class = _build_connection_vlan_form(BareCableForm, CableVLANAssignment, "cable")
+        with patch(
+            "netbox_utilities.runtime._get_database_settings",
+            return_value={"tenant_required": True},
+        ):
+            form = form_class(instance=cable)
+        form._errors = ErrorDict()
+        form.cleaned_data = {FORM_FIELD: []}
+        with patch.object(Cable, "save"):
+            form.save()
+
+        assignment_objects.filter.assert_called_with(cable=cable)
+        assignment_objects.filter.return_value.delete.assert_called_once_with()
+        assignment_objects.get_or_create.assert_not_called()

netbox_utilities/tests/test_middleware.py

@@ -1,6 +1,7 @@
 from types import SimpleNamespace
 from unittest.mock import patch
 
+from django.http import HttpResponse
 from django.test import RequestFactory, SimpleTestCase
 
 from netbox_utilities.middleware import GlobalTenantFilterMiddleware
@@ -28,6 +29,21 @@ class GlobalTenantFilterMiddlewareTest(SimpleTestCase):
     def setUp(self):
         self.factory = RequestFactory()
 
+    @patch("netbox_utilities.topology_views.apply_topology_rack_widths")
+    @patch("netbox_utilities.middleware.GlobalTenantFilterMiddleware._get_selected_scope", return_value=None)
+    def test_processes_topology_widths_after_the_view_response(self, _scope, apply_widths):
+        native_response = HttpResponse("native topology")
+        final_response = HttpResponse("width-aware topology")
+        apply_widths.return_value = final_response
+        middleware = GlobalTenantFilterMiddleware(lambda _request: native_response)
+        request = self.factory.get("/plugins/netbox_topology_views/rack-elevation/?rack_id=3")
+        request.session = {}
+
+        result = middleware(request)
+
+        self.assertIs(result, final_response)
+        apply_widths.assert_called_once_with(request, native_response)
+
     @patch("netbox_utilities.middleware.resolve")
     def test_injects_and_overrides_tenant_id(self, mocked_resolve):
         mocked_resolve.return_value = resolver_match(TenantFilterSet)

netbox_utilities/tests/test_netbox_export.py

@@ -0,0 +1,285 @@
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+from django.core.exceptions import ValidationError
+from django.test import SimpleTestCase
+
+from netbox_utilities.netbox_export import (
+    PATCH_MARKER,
+    PATCH_VERSION,
+    RACK_WIDTH_RECORD_KEY,
+    WidthAwareDeferredDevicePlacement,
+    _apply_rack_widths,
+    _defer_rack_width,
+    _serialize_rack_width,
+    _width_aware_device_placement_conflicts,
+    install_netbox_export_rack_width_support,
+)
+
+
+class FakeQuerySet(list):
+    def __init__(self, values=()):
+        super().__init__(values)
+        self.selected_related = []
+
+    def select_for_update(self):
+        return self
+
+    def select_related(self, *args):
+        self.selected_related.append(args)
+        return self
+
+    def filter(self, **kwargs):
+        values = self
+        if kwargs.get("position__isnull") is False:
+            values = [item for item in values if item.position is not None]
+        result = FakeQuerySet(values)
+        result.selected_related = self.selected_related
+        return result
+
+    def exclude(self, **kwargs):
+        pk = kwargs.get("pk")
+        result = FakeQuerySet(item for item in self if item.pk != pk)
+        result.selected_related = self.selected_related
+        return result
+
+
+class FakeDevice:
+    _meta = SimpleNamespace(label_lower="dcim.device")
+    _default_manager = FakeQuerySet()
+
+    def __init__(self, pk, *, width=1, horizontal_position=1, position=None, face="front", full_depth=False):
+        self.pk = pk
+        self.rack_id = 1 if position is not None else None
+        self.position = position
+        self.face = face
+        self.device_type = SimpleNamespace(u_height=1, is_full_depth=full_depth)
+        if width != 1:
+            self.netbox_utilities_rack_placement = SimpleNamespace(
+                width=width,
+                horizontal_position=horizontal_position,
+            )
+
+
+class NetBoxExportRackWidthTest(SimpleTestCase):
+    def test_connection_vlan_assignments_remain_exportable(self):
+        from netbox_export.services.graph import is_exportable_model
+
+        from netbox_utilities.models import CableVLANAssignment, WirelessLinkVLANAssignment
+
+        self.assertTrue(is_exportable_model(CableVLANAssignment))
+        self.assertTrue(is_exportable_model(WirelessLinkVLANAssignment))
+
+    def test_export_embeds_partial_and_full_rack_widths_on_devices(self):
+        partial = FakeDevice(1, width=2, horizontal_position=2)
+        full = FakeDevice(2)
+        original = lambda obj, *args, **kwargs: {"id": f"dcim.device:{obj.pk}"}
+
+        partial_record = _serialize_rack_width(original, partial)
+        full_record = _serialize_rack_width(original, full)
+
+        self.assertEqual(
+            partial_record[RACK_WIDTH_RECORD_KEY],
+            {"schema_version": 1, "width": 2, "horizontal_position": 2},
+        )
+        self.assertEqual(
+            full_record[RACK_WIDTH_RECORD_KEY],
+            {"schema_version": 1, "width": 1, "horizontal_position": 1},
+        )
+
+    def test_import_reads_width_metadata_without_breaking_legacy_archives(self):
+        native = SimpleNamespace(rack_spec={"ref": "dcim.rack:2"}, position=11, face="front")
+        original = MagicMock(return_value=({"fields": {}}, native))
+        record = {
+            "id": "dcim.device:334",
+            RACK_WIDTH_RECORD_KEY: {
+                "schema_version": 1,
+                "width": 2,
+                "horizontal_position": 2,
+            },
+        }
+
+        prepared, placement = _defer_rack_width(original, FakeDevice, record)
+
+        self.assertEqual(prepared, {"fields": {}})
+        self.assertEqual(
+            placement,
+            WidthAwareDeferredDevicePlacement(
+                rack_spec={"ref": "dcim.rack:2"},
+                position=11,
+                face="front",
+                width=2,
+                horizontal_position=2,
+            ),
+        )
+
+        legacy_record = {"id": "dcim.device:334"}
+        self.assertIs(_defer_rack_width(original, FakeDevice, legacy_record)[1], native)
+
+    @patch("netbox_utilities.netbox_export.normalize_width_position", side_effect=ValidationError("invalid"))
+    def test_invalid_width_metadata_falls_back_to_native_import(self, _normalize):
+        native = SimpleNamespace(rack_spec=None, position=11, face="front")
+        original = MagicMock(return_value=({}, native))
+        record = {
+            "id": "dcim.device:334",
+            RACK_WIDTH_RECORD_KEY: {
+                "schema_version": 1,
+                "width": 9,
+                "horizontal_position": 9,
+            },
+        }
+
+        self.assertIs(_defer_rack_width(original, FakeDevice, record)[1], native)
+
+    @patch("netbox_utilities.netbox_export.DeviceRackPlacement.objects")
+    def test_import_conflicts_respect_horizontal_rack_positions(self, placement_objects):
+        left = FakeDevice(1, width=2, horizontal_position=1, position=11)
+        right = FakeDevice(2, width=2, horizontal_position=2)
+        right.rack_id = 1
+        FakeDevice._default_manager = FakeQuerySet([left])
+        stored_left = SimpleNamespace(device_id=1, width=2, horizontal_position=1)
+        placement_objects.select_for_update.return_value.filter.return_value = [stored_left]
+        original = MagicMock()
+
+        conflicts = _width_aware_device_placement_conflicts(original, right, object(), 11, "front")
+
+        self.assertEqual(conflicts, [])
+        original.assert_not_called()
+        self.assertEqual(FakeDevice._default_manager.selected_related, [("device_type",)])
+        placement_objects.select_for_update.return_value.filter.assert_called_with(device_id__in=[1])
+
+        overlapping = FakeDevice(3, width=2, horizontal_position=1)
+        overlapping.rack_id = 1
+        self.assertEqual(
+            _width_aware_device_placement_conflicts(original, overlapping, object(), 11, "front"),
+            [left],
+        )
+
+    @patch("netbox_utilities.netbox_export.DeviceRackPlacement.objects")
+    def test_import_persists_partial_width_and_removes_stale_full_width(self, placement_objects):
+        partial = FakeDevice(1)
+        full = FakeDevice(2, width=2, horizontal_position=2)
+        partial_placement = WidthAwareDeferredDevicePlacement(None, 11, "front", 2, 1)
+        full_placement = WidthAwareDeferredDevicePlacement(None, 12, "front", 1, 1)
+        placements = [("partial", partial_placement), ("full", full_placement)]
+        resolved = {"partial": partial, "full": full}
+
+        def native_apply(received, *_args, **_kwargs):
+            self.assertEqual(received, placements)
+            self.assertEqual(partial._netbox_utilities_rack_width, 2)
+            self.assertEqual(full._netbox_utilities_rack_width, 1)
+            placement_objects.update_or_create.assert_called_once_with(
+                device=partial,
+                defaults={"width": 2, "horizontal_position": 1},
+            )
+            placement_objects.filter.assert_called_once_with(device=full)
+            placement_objects.filter.return_value.delete.assert_called_once_with()
+            partial.rack_id = full.rack_id = 1
+            partial.position = 11
+            full.position = 12
+            return "saved"
+
+        result = _apply_rack_widths(native_apply, placements, resolved, object(), object())
+
+        self.assertEqual(result, "saved")
+        self.assertEqual(placement_objects.update_or_create.call_count, 2)
+        self.assertEqual(placement_objects.filter.call_count, 2)
+        self.assertEqual(placement_objects.filter.return_value.delete.call_count, 2)
+
+    @patch("netbox_utilities.netbox_export.DeviceRackPlacement.objects")
+    def test_import_preloads_all_partial_widths_before_native_placement(self, placement_objects):
+        left = FakeDevice(1)
+        right = FakeDevice(2)
+        placements = [
+            ("left", WidthAwareDeferredDevicePlacement(None, 11, "front", 2, 1)),
+            ("right", WidthAwareDeferredDevicePlacement(None, 11, "front", 2, 2)),
+        ]
+        resolved = {"left": left, "right": right}
+
+        def native_apply(*_args, **_kwargs):
+            self.assertEqual(placement_objects.update_or_create.call_count, 2)
+            self.assertEqual(
+                [call.kwargs["device"] for call in placement_objects.update_or_create.call_args_list],
+                [left, right],
+            )
+            left.rack_id = right.rack_id = 1
+            left.position = right.position = 11
+
+        _apply_rack_widths(native_apply, placements, resolved, object(), object())
+
+        self.assertEqual(placement_objects.update_or_create.call_count, 4)
+
+    @patch("netbox_utilities.netbox_export.DeviceRackPlacement.objects")
+    def test_two_partial_devices_remain_in_the_same_unit_during_import(self, placement_objects):
+        left = FakeDevice(1)
+        right = FakeDevice(2)
+        FakeDevice._default_manager = FakeQuerySet([left, right])
+        placements = [
+            ("left", WidthAwareDeferredDevicePlacement(None, 11, "front", 2, 1)),
+            ("right", WidthAwareDeferredDevicePlacement(None, 11, "front", 2, 2)),
+        ]
+        resolved = {"left": left, "right": right}
+        stored = {}
+
+        def store_width(*, device, defaults):
+            stored[device.pk] = SimpleNamespace(device_id=device.pk, **defaults)
+
+        def locked_widths(**kwargs):
+            return [stored[pk] for pk in kwargs["device_id__in"] if pk in stored]
+
+        placement_objects.update_or_create.side_effect = store_width
+        placement_objects.select_for_update.return_value.filter.side_effect = locked_widths
+
+        def native_apply(received, *_args, **_kwargs):
+            for record_id, placement in received:
+                device = resolved[record_id]
+                conflicts = _width_aware_device_placement_conflicts(
+                    MagicMock(),
+                    device,
+                    object(),
+                    placement.position,
+                    placement.face,
+                )
+                self.assertEqual(conflicts, [])
+                device.rack_id = 1
+                device.position = placement.position
+                device.face = placement.face
+
+        _apply_rack_widths(native_apply, placements, resolved, object(), object())
+
+        self.assertEqual(left.position, 11)
+        self.assertEqual(right.position, 11)
+
+    @patch("netbox_utilities.netbox_export.import_module")
+    @patch("netbox_utilities.netbox_export.apps.get_app_config")
+    @patch("netbox_utilities.netbox_export.apps.is_installed", return_value=True)
+    def test_installer_patches_supported_netbox_export(self, _installed, get_config, import_module):
+        get_config.return_value = SimpleNamespace(version="0.3.11")
+        exporter = SimpleNamespace(serialize_object=lambda *args, **kwargs: {})
+        graph = SimpleNamespace(is_exportable_model=lambda model: False)
+        importer = SimpleNamespace(
+            _defer_device_placement=lambda *args, **kwargs: ({}, None),
+            _device_placement_conflicts=lambda *args, **kwargs: [],
+            _apply_device_placements=lambda *args, **kwargs: None,
+        )
+        import_module.side_effect = [exporter, graph, importer]
+
+        self.assertTrue(install_netbox_export_rack_width_support())
+
+        for module, name in (
+            (exporter, "serialize_object"),
+            (graph, "is_exportable_model"),
+            (importer, "_defer_device_placement"),
+            (importer, "_device_placement_conflicts"),
+            (importer, "_apply_device_placements"),
+        ):
+            self.assertEqual(getattr(getattr(module, name), PATCH_MARKER), PATCH_VERSION)
+
+    @patch("netbox_utilities.netbox_export.import_module")
+    @patch("netbox_utilities.netbox_export.apps.get_app_config")
+    @patch("netbox_utilities.netbox_export.apps.is_installed", return_value=True)
+    def test_installer_ignores_unsupported_netbox_export(self, _installed, get_config, import_module):
+        get_config.return_value = SimpleNamespace(version="0.4.0")
+
+        self.assertFalse(install_netbox_export_rack_width_support())
+        import_module.assert_not_called()

netbox_utilities/tests/test_optional_integration_pages.py

@@ -0,0 +1,23 @@
+from django.conf import settings
+from django.contrib.auth.context_processors import PermWrapper
+from django.contrib.auth.models import AnonymousUser
+from django.test import RequestFactory, SimpleTestCase
+
+from netbox_utilities.template_content import UtilitiesGlobalContent
+
+
+class OptionalRackIntegrationHeadTest(SimpleTestCase):
+    def test_foreign_rack_adapters_are_not_loaded_by_the_global_head(self):
+        request = RequestFactory().get("/dcim/racks/3/reorder/")
+        request.user = AnonymousUser()
+        html = UtilitiesGlobalContent(
+            {
+                "request": request,
+                "settings": settings,
+                "csrf_token": "",
+                "perms": PermWrapper(request.user),
+            }
+        ).head()
+
+        self.assertNotIn("netbox-utilities-reorder-rack-width-data", html)
+        self.assertNotIn("netbox-utilities-topology-rack-width-data", html)

netbox_utilities/tests/test_patchpanel.py

@@ -1,9 +1,17 @@
+from importlib import import_module
 from types import SimpleNamespace
 from unittest.mock import MagicMock, patch
 
 from django.test import SimpleTestCase
 
-from netbox_utilities.patchpanel import is_patchpanel, pair_ports, port_identifier, retrace_patchpanel_paths
+from netbox_utilities.patchpanel import (
+    _component_saved,
+    _wrap_component_container_save,
+    is_patchpanel,
+    pair_ports,
+    port_identifier,
+    retrace_patchpanel_paths,
+)
 
 
 def port(pk, name):
@@ -11,6 +19,53 @@ def port(pk, name):
 
 
 class PatchpanelPairingTest(SimpleTestCase):
+    @patch("netbox_utilities.patchpanel.synchronize_patchpanel")
+    def test_component_edits_do_not_trigger_automation(self, synchronize):
+        component = SimpleNamespace(device_id=42)
+
+        _component_saved(None, component, created=False)
+
+        synchronize.assert_not_called()
+
+    @patch("netbox_utilities.patchpanel.synchronize_patchpanel")
+    def test_new_components_trigger_automation(self, synchronize):
+        component = SimpleNamespace(device_id=42)
+
+        _component_saved(None, component, created=True)
+
+        synchronize.assert_called_once_with(42)
+
+    @patch("netbox_utilities.patchpanel.synchronize_patchpanel")
+    def test_existing_device_save_does_not_trigger_automation(self, synchronize):
+        class Container:
+            def __init__(self, adding):
+                self._state = SimpleNamespace(adding=adding)
+                self.pk = 42
+
+            def save(self):
+                self._state.adding = False
+                return "saved"
+
+        _wrap_component_container_save(Container, lambda instance: instance.pk)
+
+        self.assertEqual(Container(adding=False).save(), "saved")
+        synchronize.assert_not_called()
+
+        self.assertEqual(Container(adding=True).save(), "saved")
+        synchronize.assert_called_once_with(42)
+
+    def test_existing_device_migrations_are_noops(self):
+        migration_names = (
+            "0004_patchpanel_port_mappings",
+            "0005_fix_patchpanel_port_number_mappings",
+            "0006_retrace_existing_patchpanel_paths",
+        )
+
+        for migration_name in migration_names:
+            with self.subTest(migration=migration_name):
+                module = import_module(f"netbox_utilities.migrations.{migration_name}")
+                self.assertEqual(module.Migration.operations, [])
+
     def test_detects_patchpanel_role_case_insensitively(self):
         self.assertTrue(is_patchpanel(SimpleNamespace(role=SimpleNamespace(name="Patchpanel"))))
         self.assertTrue(is_patchpanel(SimpleNamespace(role=SimpleNamespace(name="PATCHPANEL"))))

netbox_utilities/tests/test_rack_width.py

@@ -0,0 +1,425 @@
+from functools import wraps
+from importlib import import_module
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import MagicMock, call, patch
+
+from django.conf import settings
+from django.contrib.auth.context_processors import PermWrapper
+from django.contrib.auth.models import AnonymousUser
+from django.core.exceptions import ValidationError
+from django.template.loader import render_to_string
+from django.test import RequestFactory, SimpleTestCase
+from django.urls import resolve, reverse
+
+from netbox_utilities.rack_width import (
+    _cleanup_unracked_placement,
+    _install_rack_methods,
+    _rack_elevation_devices,
+    available_units_for_device,
+    effective_width_positions,
+    horizontal_interval,
+    include_rack_width_in_fieldsets,
+    intervals_cover_full_width,
+    intervals_overlap,
+    normalize_width_position,
+    placement_rectangles_overlap,
+    stage_width_position,
+)
+
+
+class RackWidthTest(SimpleTestCase):
+    def test_rack_width_javascript_synchronizes_netbox_tom_select(self):
+        script = (Path(__file__).parents[1] / "static" / "netbox_utilities" / "forms.js").read_text(encoding="utf-8")
+
+        self.assertIn("positionField.disabled = width === 1", script)
+        self.assertIn("positionField.tomselect.sync()", script)
+
+    def test_svg_devices_include_core_device_bay_annotation_and_optional_placement(self):
+        from dcim.choices import DeviceFaceChoices
+        from dcim.models import Rack
+
+        devices = _rack_elevation_devices(Rack(pk=3), DeviceFaceChoices.FACE_FRONT)
+
+        self.assertIn("devicebay_count", devices.query.annotations)
+        self.assertIn("netbox_utilities_rack_placement", devices.query.select_related)
+        self.assertIn("device_type", devices.query.select_related)
+        self.assertIn("manufacturer", devices.query.select_related["device_type"])
+        self.assertNotIn("netbox_utilities_rack_placement__isnull", str(devices.query))
+
+    def test_core_rack_units_remain_available_to_other_plugins(self):
+        from dcim.models import Rack
+
+        self.assertEqual(Rack.get_rack_units.__module__, "dcim.models.racks")
+        self.assertFalse(hasattr(Rack.get_rack_units, "__wrapped__"))
+
+    def test_replaces_legacy_rack_unit_wrapper_during_upgrade(self):
+        def native_rack_units(rack):
+            return rack
+
+        def native_available_units(rack, *args, **kwargs):
+            return rack, args, kwargs
+
+        @wraps(native_rack_units)
+        def legacy_rack_units(rack):
+            return native_rack_units(rack)
+
+        @wraps(native_available_units)
+        def legacy_available_units(rack, *args, **kwargs):
+            return native_available_units(rack, *args, **kwargs)
+
+        class LegacyRack:
+            get_rack_units = legacy_rack_units
+            get_available_units = legacy_available_units
+            _netbox_utilities_rack_width_installed = True
+
+        with patch.dict("sys.modules", {"dcim.models": SimpleNamespace(Rack=LegacyRack)}):
+            _install_rack_methods()
+
+        self.assertIs(LegacyRack.get_rack_units, native_rack_units)
+        self.assertIs(LegacyRack.get_available_units.__wrapped__, native_available_units)
+        self.assertEqual(LegacyRack._netbox_utilities_rack_width_version, 2)
+
+    def test_svg_draws_all_partial_devices_sharing_one_unit_exactly_once(self):
+        from dcim.svg.racks import RackElevationSVG
+
+        regular = SimpleNamespace(
+            pk=1,
+            rack_id=3,
+            face="front",
+            position=12,
+            device_type=SimpleNamespace(u_height=1),
+            netbox_utilities_rack_placement=None,
+        )
+        partial_right = SimpleNamespace(
+            pk=2,
+            rack_id=3,
+            face="front",
+            position=11,
+            device_type=SimpleNamespace(u_height=1),
+            netbox_utilities_rack_placement=SimpleNamespace(width=2, horizontal_position=2),
+        )
+        partial_left = SimpleNamespace(
+            pk=3,
+            rack_id=3,
+            face="front",
+            position=11,
+            device_type=SimpleNamespace(u_height=1),
+            netbox_utilities_rack_placement=SimpleNamespace(width=2, horizontal_position=1),
+        )
+        rack = SimpleNamespace(get_rack_units=MagicMock())
+        elevation = SimpleNamespace(
+            rack=rack,
+            unit_width=200,
+            unit_height=20,
+            permitted_device_ids={1, 2, 3},
+            drawing=SimpleNamespace(add=MagicMock()),
+            _get_device_coords=MagicMock(return_value=(10, 20)),
+            draw_device_front=MagicMock(),
+            draw_device_rear=MagicMock(),
+        )
+
+        with patch(
+            "netbox_utilities.rack_width._rack_elevation_devices",
+            return_value=[regular, partial_left, partial_right],
+        ):
+            RackElevationSVG.draw_face(elevation, "front")
+
+        rack.get_rack_units.assert_not_called()
+        self.assertEqual(
+            elevation.draw_device_front.call_args_list,
+            [
+                call(regular, (10, 20), (200, 20)),
+                call(partial_left, (10.0, 20), (100.0, 20)),
+                call(partial_right, (110.0, 20), (100.0, 20)),
+            ],
+        )
+
+    def test_infers_two_half_widths_when_legacy_devices_share_one_unit(self):
+        devices = [
+            SimpleNamespace(
+                pk=21,
+                rack_id=3,
+                face="front",
+                position=11,
+                device_type=SimpleNamespace(u_height=1),
+                netbox_utilities_rack_placement=None,
+            ),
+            SimpleNamespace(
+                pk=22,
+                rack_id=3,
+                face="front",
+                position=11,
+                device_type=SimpleNamespace(u_height=1),
+                netbox_utilities_rack_placement=None,
+            ),
+        ]
+
+        self.assertEqual(
+            effective_width_positions(devices),
+            {
+                21: (2, 1, "inferred"),
+                22: (2, 2, "inferred"),
+            },
+        )
+
+    def test_infers_missing_position_next_to_stored_half_width(self):
+        devices = [
+            SimpleNamespace(
+                pk=31,
+                rack_id=3,
+                face="front",
+                position=11,
+                device_type=SimpleNamespace(u_height=1),
+                netbox_utilities_rack_placement=SimpleNamespace(width=2, horizontal_position=2),
+            ),
+            SimpleNamespace(
+                pk=32,
+                rack_id=3,
+                face="front",
+                position=11,
+                device_type=SimpleNamespace(u_height=1),
+                netbox_utilities_rack_placement=None,
+            ),
+        ]
+
+        self.assertEqual(
+            effective_width_positions(devices),
+            {
+                31: (2, 2, "stored"),
+                32: (2, 1, "inferred"),
+            },
+        )
+
+    def test_adds_rack_width_fields_to_existing_location_fieldset(self):
+        from utilities.forms.rendering import FieldSet
+
+        original = (FieldSet("site", "rack", "position", "latitude", name="Location"),)
+
+        extended = include_rack_width_in_fieldsets(original)
+
+        self.assertEqual(
+            extended[0].items,
+            (
+                "site",
+                "rack",
+                "position",
+                "utilities_rack_width",
+                "utilities_horizontal_position",
+                "latitude",
+            ),
+        )
+        self.assertEqual(original[0].items, ("site", "rack", "position", "latitude"))
+
+    def test_appends_visible_fallback_fieldset_when_position_is_missing(self):
+        from utilities.forms.rendering import FieldSet
+
+        extended = include_rack_width_in_fieldsets((FieldSet("name", name="Device"),))
+
+        self.assertEqual(extended[-1].name, "Rackbreite im Rack")
+        self.assertEqual(extended[-1].items, ("utilities_rack_width", "utilities_horizontal_position"))
+
+    def test_device_edit_view_uses_explicit_rack_width_form(self):
+        from netbox.registry import registry
+
+        for action in ("add", "edit"):
+            device_view = next(view["view"] for view in registry["views"]["dcim"]["device"] if view["name"] == action)
+
+            self.assertEqual(device_view.__name__, "RackWidthDeviceEditView")
+            self.assertEqual(device_view.form.__name__, "RackWidthDeviceForm")
+            self.assertEqual(device_view.template_name, "netbox_utilities/device_edit.html")
+            self.assertEqual(device_view.htmx_template_name, "netbox_utilities/device_edit_form.html")
+            self.assertIn("utilities_rack_width", device_view.form.base_fields)
+            self.assertIn("utilities_horizontal_position", device_view.form.base_fields)
+
+    def test_resolved_device_edit_page_renders_rack_width_fields(self):
+        from dcim.models import Device
+
+        object_type = SimpleNamespace(pk=1, model_class=lambda: Device)
+        with (
+            patch("core.models.ObjectType.objects.get_for_model", return_value=object_type),
+            patch(
+                "django.contrib.contenttypes.models.ContentType.objects.get_for_model",
+                return_value=object_type,
+            ),
+            patch("extras.models.CustomField.objects.get_for_model", return_value=[]),
+            patch(
+                "netbox_utilities.runtime._get_database_settings",
+                return_value={"tenant_required": True},
+            ),
+        ):
+            url = reverse("dcim:device_edit", kwargs={"pk": 1})
+            view_class = resolve(url).func.view_class
+            form = view_class.form()
+            request = self._anonymous_request()
+            context = {
+                "form": form,
+                "object": SimpleNamespace(
+                    pk=None,
+                    _meta=Device._meta,
+                    device_type=SimpleNamespace(is_child_device=False),
+                    parent_bay=None,
+                ),
+                "return_url": "/dcim/devices/",
+                "request": request,
+                "settings": settings,
+                "csrf_token": "",
+                "perms": PermWrapper(request.user),
+            }
+            rendered_pages = (
+                render_to_string(view_class.htmx_template_name, context),
+                render_to_string(view_class.template_name, context),
+            )
+
+        rack_position = 'name="position"'
+        width = 'name="utilities_rack_width"'
+        horizontal_position = 'name="utilities_horizontal_position"'
+        latitude = 'name="latitude"'
+        for html in rendered_pages:
+            self.assertIn(width, html)
+            self.assertIn(horizontal_position, html)
+            self.assertLess(html.index(rack_position), html.index(width))
+            self.assertLess(html.index(width), html.index(horizontal_position))
+            self.assertLess(html.index(horizontal_position), html.index(latitude))
+
+    def test_resolved_device_add_page_renders_rack_width_fields(self):
+        from dcim.models import Device
+
+        object_type = SimpleNamespace(pk=1, model_class=lambda: Device)
+        with (
+            patch("core.models.ObjectType.objects.get_for_model", return_value=object_type),
+            patch(
+                "django.contrib.contenttypes.models.ContentType.objects.get_for_model",
+                return_value=object_type,
+            ),
+            patch("extras.models.CustomField.objects.get_for_model", return_value=[]),
+            patch(
+                "netbox_utilities.runtime._get_database_settings",
+                return_value={"tenant_required": True},
+            ),
+        ):
+            view_class = resolve(reverse("dcim:device_add")).func.view_class
+            form = view_class.form()
+            request = self._anonymous_request()
+            context = {
+                "form": form,
+                "object": SimpleNamespace(
+                    pk=None,
+                    _meta=Device._meta,
+                    device_type=SimpleNamespace(is_child_device=False),
+                    parent_bay=None,
+                ),
+                "return_url": "/dcim/devices/",
+                "request": request,
+                "settings": settings,
+                "csrf_token": "",
+                "perms": PermWrapper(request.user),
+            }
+            rendered_pages = (
+                render_to_string(view_class.htmx_template_name, context),
+                render_to_string(view_class.template_name, context),
+            )
+
+        for html in rendered_pages:
+            self.assertIn('name="utilities_rack_width"', html)
+            self.assertIn('name="utilities_horizontal_position"', html)
+
+    def test_bound_device_form_clean_handles_netbox_clean_returning_none(self):
+        from dcim.models import Device
+        from netbox.registry import registry
+
+        edit_view = next(view["view"] for view in registry["views"]["dcim"]["device"] if view["name"] == "edit")
+        object_type = SimpleNamespace(pk=1, model_class=lambda: Device)
+        with (
+            patch("core.models.ObjectType.objects.get_for_model", return_value=object_type),
+            patch(
+                "django.contrib.contenttypes.models.ContentType.objects.get_for_model",
+                return_value=object_type,
+            ),
+            patch("extras.models.CustomField.objects.get_for_model", return_value=[]),
+            patch(
+                "netbox_utilities.runtime._get_database_settings",
+                return_value={"tenant_required": True},
+            ),
+        ):
+            form = edit_view.form(data={})
+            # NetBox 4.6.7's CheckLastUpdatedMixin.clean() updates
+            # self.cleaned_data but deliberately returns None.
+            with patch.object(form, "_post_clean"):
+                self.assertFalse(form.is_valid())
+            self.assertIsInstance(form.cleaned_data, dict)
+
+    @staticmethod
+    def _anonymous_request():
+        request = RequestFactory().get("/dcim/devices/1/edit/")
+        request.user = AnonymousUser()
+        return request
+
+    def test_normalizes_full_width_to_first_position(self):
+        self.assertEqual(normalize_width_position(1, 4), (1, 1))
+
+    def test_rejects_position_outside_selected_width(self):
+        with self.assertRaises(ValidationError):
+            normalize_width_position(2, 3)
+
+    def test_adjacent_half_widths_do_not_overlap(self):
+        self.assertFalse(intervals_overlap(horizontal_interval(2, 1), horizontal_interval(2, 2)))
+
+    def test_half_width_overlaps_full_width(self):
+        self.assertTrue(intervals_overlap(horizontal_interval(1, 1), horizontal_interval(2, 2)))
+
+    def test_two_halves_cover_full_width(self):
+        self.assertTrue(intervals_cover_full_width([horizontal_interval(2, 1), horizontal_interval(2, 2)]))
+
+    def test_single_half_does_not_cover_full_width(self):
+        self.assertFalse(intervals_cover_full_width([horizontal_interval(2, 1)]))
+
+    def test_same_unit_adjacent_devices_do_not_collide(self):
+        self.assertFalse(placement_rectangles_overlap(10, 1, 2, 1, 10, 1, 2, 2))
+
+    def test_multi_unit_device_collides_only_on_same_horizontal_area(self):
+        self.assertTrue(placement_rectangles_overlap(10, 2, 2, 1, 11, 1, 2, 1))
+        self.assertFalse(placement_rectangles_overlap(10, 2, 2, 1, 11, 1, 2, 2))
+
+    def test_stages_width_without_requiring_an_already_assigned_rack(self):
+        device = SimpleNamespace()
+
+        stage_width_position(device, 2, 2)
+
+        self.assertEqual(device._netbox_utilities_rack_width, 2)
+        self.assertEqual(device._netbox_utilities_horizontal_position, 2)
+
+    @patch("netbox_utilities.rack_width.find_placement_conflict", return_value=None)
+    def test_current_position_is_available_without_conflict(self, _find_conflict):
+        rack = SimpleNamespace(units=[1, 1.5, 2, 2.5])
+        device = SimpleNamespace(
+            position=1,
+            device_type=SimpleNamespace(u_height=1),
+        )
+
+        self.assertEqual(available_units_for_device(rack, device), [1])
+
+    @patch("netbox_utilities.rack_width.DeviceRackPlacement.objects")
+    def test_unracked_device_removes_stale_width(self, placement_objects):
+        device = SimpleNamespace(pk=12, rack_id=None, position=None)
+
+        _cleanup_unracked_placement(None, device, using="default")
+
+        placement_objects.using.assert_called_once_with("default")
+        placement_objects.using.return_value.filter.assert_called_once_with(device_id=12)
+        placement_objects.using.return_value.filter.return_value.delete.assert_called_once_with()
+
+
+class RackWidthMigrationTest(SimpleTestCase):
+    def test_postgresql_migration_drops_core_uniqueness(self):
+        migration = import_module("netbox_utilities.migrations.0007_devicerackplacement")
+        schema_editor = SimpleNamespace(
+            connection=SimpleNamespace(vendor="postgresql"),
+            execute=MagicMock(),
+        )
+
+        migration.drop_core_rack_position_constraint(None, schema_editor)
+
+        statement = schema_editor.execute.call_args.args[0]
+        self.assertIn("DROP CONSTRAINT IF EXISTS", statement)
+        self.assertIn("dcim_device_unique_rack_position_face", statement)

netbox_utilities/tests/test_reorder_rack.py

@@ -1,16 +1,24 @@
 from decimal import Decimal
+from pathlib import Path
 from types import SimpleNamespace
 from unittest.mock import MagicMock, patch
 
-from django.test import SimpleTestCase
+from django.template.loader import get_template, render_to_string
+from django.test import RequestFactory, SimpleTestCase
+from django.urls import resolve, reverse
 from rest_framework.exceptions import PermissionDenied
 
 from netbox_utilities.reorder_rack import (
     RackLayoutError,
     apply_rack_layout,
     bulk_reorder_update,
+    get_reorder_rack_width_data,
+    grid_dimensions,
+    horizontal_position_from_grid_x,
     install_reorder_rack_bulk_save,
     parse_device_placements,
+    reorder_grid_y,
+    width_aware_reorder_get,
 )
 
 
@@ -32,14 +40,41 @@ class RackLayoutParsingTest(SimpleTestCase):
         )
 
         self.assertEqual(
-            [(item.device_id, item.position, item.face) for item in placements],
+            [(item.device_id, item.position, item.face, item.grid_x) for item in placements],
             [
-                (10, Decimal(4), "front"),
-                (11, Decimal("8.5"), "front"),
-                (12, None, ""),
+                (10, Decimal(4), "front", None),
+                (11, Decimal("8.5"), "front", None),
+                (12, None, "", None),
             ],
         )
 
+    def test_reads_horizontal_positions_only_from_marked_twelve_column_payload(self):
+        placements = parse_device_placements(
+            rack_layout(front=[{"id": 10, "x": 6, "y": 4}]),
+            grid_columns=12,
+        )
+
+        self.assertEqual(placements[0].grid_x, 6)
+
+    def test_maps_rack_widths_to_twelve_column_grid(self):
+        self.assertEqual(grid_dimensions(1, 1), (12, 0))
+        self.assertEqual(grid_dimensions(2, 2), (6, 6))
+        self.assertEqual(grid_dimensions(3, 2), (4, 4))
+        self.assertEqual(grid_dimensions(4, 4), (3, 9))
+
+    def test_maps_grid_x_back_to_horizontal_position(self):
+        self.assertEqual(horizontal_position_from_grid_x(2, 6), 2)
+        self.assertEqual(horizontal_position_from_grid_x(3, 8), 3)
+        self.assertEqual(horizontal_position_from_grid_x(4, 9), 4)
+
+    def test_rejects_misaligned_grid_position(self):
+        with self.assertRaisesMessage(RackLayoutError, "nicht zulässig"):
+            horizontal_position_from_grid_x(2, 3)
+
+    def test_rejects_non_integer_grid_position(self):
+        with self.assertRaisesMessage(RackLayoutError, "ganze Zahl"):
+            horizontal_position_from_grid_x(2, 6.0)
+
     def test_rejects_duplicate_devices(self):
         with self.assertRaisesMessage(RackLayoutError, "mehrfach"):
             parse_device_placements(
@@ -55,12 +90,30 @@ class RackLayoutParsingTest(SimpleTestCase):
 
 
 class ApplyRackLayoutTest(SimpleTestCase):
+    @patch("netbox_utilities.reorder_rack.DeviceRackPlacement")
     @patch("netbox_utilities.reorder_rack.get_permission_for_model", return_value="dcim.change_device")
     @patch("netbox_utilities.reorder_rack.Device")
-    def test_clears_all_old_positions_before_saving_targets(self, device_model, _get_permission):
+    def test_clears_all_old_positions_before_saving_targets(
+        self,
+        device_model,
+        _get_permission,
+        placement_model,
+    ):
         events = []
-        first = MagicMock(pk=10, position=Decimal(1), face="front")
-        second = MagicMock(pk=11, position=Decimal(2), face="front")
+        first = MagicMock(
+            pk=10,
+            rack_id=5,
+            position=Decimal(1),
+            face="front",
+            device_type=SimpleNamespace(u_height=1),
+        )
+        second = MagicMock(
+            pk=11,
+            rack_id=5,
+            position=Decimal(2),
+            face="front",
+            device_type=SimpleNamespace(u_height=1),
+        )
         first.snapshot.side_effect = lambda: events.append("snapshot-10")
         second.snapshot.side_effect = lambda: events.append("snapshot-11")
         first.full_clean.side_effect = lambda: events.append("validate-10")
@@ -70,6 +123,7 @@ class ApplyRackLayoutTest(SimpleTestCase):
 
         device_model.objects.select_for_update.return_value.filter.return_value = [first, second]
         device_model.objects.filter.return_value.update.side_effect = lambda **_kwargs: events.append("clear")
+        placement_model.objects.select_for_update.return_value.filter.return_value = []
         user = MagicMock()
         user.has_perm.return_value = True
         placements = parse_device_placements(rack_layout(front=[{"id": 10, "y": 2}, {"id": 11, "y": 1}]))
@@ -83,11 +137,19 @@ class ApplyRackLayoutTest(SimpleTestCase):
         self.assertEqual((first.position, first.face), (Decimal(2), "front"))
         self.assertEqual((second.position, second.face), (Decimal(1), "front"))
 
+    @patch("netbox_utilities.reorder_rack.DeviceRackPlacement")
     @patch("netbox_utilities.reorder_rack.get_permission_for_model", return_value="dcim.change_device")
     @patch("netbox_utilities.reorder_rack.Device")
-    def test_rejects_changed_device_without_permission(self, device_model, _get_permission):
-        device = MagicMock(pk=10, position=Decimal(1), face="front")
+    def test_rejects_changed_device_without_permission(self, device_model, _get_permission, placement_model):
+        device = MagicMock(
+            pk=10,
+            rack_id=5,
+            position=Decimal(1),
+            face="front",
+            device_type=SimpleNamespace(u_height=1),
+        )
         device_model.objects.select_for_update.return_value.filter.return_value = [device]
+        placement_model.objects.select_for_update.return_value.filter.return_value = []
         user = MagicMock()
         user.has_perm.return_value = False
         placements = parse_device_placements(rack_layout(front=[{"id": 10, "y": 2}]))
@@ -98,27 +160,499 @@ class ApplyRackLayoutTest(SimpleTestCase):
         device_model.objects.filter.assert_not_called()
         device.save.assert_not_called()
 
+    @patch("netbox_utilities.reorder_rack.DeviceRackPlacement")
+    @patch("netbox_utilities.reorder_rack.get_permission_for_model", return_value="dcim.change_device")
+    @patch("netbox_utilities.reorder_rack.Device")
+    def test_saves_horizontal_only_move_for_partial_width_device(
+        self,
+        device_model,
+        _get_permission,
+        placement_model,
+    ):
+        device = MagicMock(
+            pk=10,
+            rack_id=5,
+            position=Decimal(4),
+            face="front",
+            device_type=SimpleNamespace(u_height=1),
+        )
+        stored = SimpleNamespace(device_id=10, width=2, horizontal_position=1)
+        device_model.objects.select_for_update.return_value.filter.return_value = [device]
+        placement_model.objects.select_for_update.return_value.filter.return_value = [stored]
+        user = MagicMock()
+        user.has_perm.return_value = True
+        placements = parse_device_placements(
+            rack_layout(front=[{"id": 10, "x": 6, "y": 4}]),
+            grid_columns=12,
+        )
+
+        changed = apply_rack_layout(rack=SimpleNamespace(pk=5), placements=placements, user=user)
+
+        self.assertEqual(changed, [device])
+        self.assertEqual(device._netbox_utilities_rack_width, 2)
+        self.assertEqual(device._netbox_utilities_horizontal_position, 2)
+        placement_model.objects.update_or_create.assert_called_once_with(
+            device=device,
+            defaults={"width": 2, "horizontal_position": 2},
+        )
+
+    @patch("netbox_utilities.reorder_rack.DeviceRackPlacement")
+    @patch("netbox_utilities.reorder_rack.get_permission_for_model", return_value="dcim.change_device")
+    @patch("netbox_utilities.reorder_rack.Device")
+    def test_legacy_payload_preserves_stored_horizontal_position(
+        self,
+        device_model,
+        _get_permission,
+        placement_model,
+    ):
+        device = MagicMock(
+            pk=10,
+            rack_id=5,
+            position=Decimal(4),
+            face="front",
+            device_type=SimpleNamespace(u_height=1),
+        )
+        stored = SimpleNamespace(device_id=10, width=2, horizontal_position=2)
+        device_model.objects.select_for_update.return_value.filter.return_value = [device]
+        placement_model.objects.select_for_update.return_value.filter.return_value = [stored]
+        user = MagicMock()
+        user.has_perm.return_value = True
+        placements = parse_device_placements(rack_layout(front=[{"id": 10, "x": 0, "y": 5}]))
+
+        changed = apply_rack_layout(rack=SimpleNamespace(pk=5), placements=placements, user=user)
+
+        self.assertEqual(changed, [device])
+        placement_model.objects.update_or_create.assert_called_once_with(
+            device=device,
+            defaults={"width": 2, "horizontal_position": 2},
+        )
+
+    @patch("netbox_utilities.reorder_rack.DeviceRackPlacement")
+    @patch("netbox_utilities.reorder_rack.get_permission_for_model", return_value="dcim.change_device")
+    @patch("netbox_utilities.reorder_rack.Device")
+    def test_persists_inferred_half_width_when_shared_device_is_moved(
+        self,
+        device_model,
+        _get_permission,
+        placement_model,
+    ):
+        left = MagicMock(
+            pk=10,
+            rack_id=5,
+            position=Decimal(4),
+            face="front",
+            device_type=SimpleNamespace(u_height=1),
+        )
+        right = MagicMock(
+            pk=11,
+            rack_id=5,
+            position=Decimal(4),
+            face="front",
+            device_type=SimpleNamespace(u_height=1),
+        )
+        device_model.objects.select_for_update.return_value.filter.return_value = [left, right]
+        placement_model.objects.select_for_update.return_value.filter.return_value = []
+        user = MagicMock()
+        user.has_perm.return_value = True
+        placements = parse_device_placements(
+            rack_layout(
+                front=[
+                    {"id": 10, "x": 0, "y": 4},
+                    {"id": 11, "x": 6, "y": 5},
+                ]
+            ),
+            grid_columns=12,
+        )
+
+        changed = apply_rack_layout(rack=SimpleNamespace(pk=5), placements=placements, user=user)
+
+        self.assertEqual(changed, [right])
+        placement_model.objects.update_or_create.assert_called_once_with(
+            device=right,
+            defaults={"width": 2, "horizontal_position": 2},
+        )
+
+
+class ReorderRackFrontendTest(SimpleTestCase):
+    def test_grid_y_matches_reorder_plugin_for_both_numbering_directions(self):
+        self.assertEqual(reorder_grid_y(SimpleNamespace(u_height=42, desc_units=True), 4, 2), 6)
+        self.assertEqual(reorder_grid_y(SimpleNamespace(u_height=42, desc_units=False), 4, 2), 74)
+
+    def test_width_adapter_runs_before_gridstack_and_preserves_original_save(self):
+        script = (Path(__file__).parents[1] / "static" / "netbox_utilities" / "reorder-rack-width.js").read_text(
+            encoding="utf-8"
+        )
+
+        self.assertIn("setAttribute(grid, 'gs-column', columns)", script)
+        self.assertIn("setAttribute(item, 'gs-w', device.grid_width)", script)
+        self.assertIn("setAttribute(item, 'gs-x', device.grid_x)", script)
+        self.assertIn("grid.on('dragstop'", script)
+        self.assertIn("grid.on('dropped'", script)
+        self.assertIn("closest('#saveButton')", script)
+        self.assertIn("X-NetBox-Utilities-Rack-Grid-Columns", script)
+        self.assertIn("if (face !== 'other')", script)
+        self.assertIn("data.schema_version !== 3", script)
+        self.assertIn("data.complete !== true", script)
+        self.assertIn("nativeMountedItems.length", script)
+        self.assertIn("const nativeItemsByFace = {}", script)
+        self.assertIn("const device = devicesById.get", script)
+        self.assertIn("if (!nativeItemsByFace[face].has", script)
+        self.assertNotIn("partialDeviceIds", script)
+        self.assertNotIn("JSON.stringify", script)
+
+    def test_server_template_uses_complete_twelve_column_device_payload(self):
+        templates = Path(__file__).parents[1] / "templates" / "netbox_utilities"
+        page = (templates / "reorder_rack.html").read_text(encoding="utf-8")
+        grid = (templates / "reorder_rack_grid.html").read_text(encoding="utf-8")
+
+        self.assertIn('include "netbox_utilities/reorder_rack_grid.html"', page)
+        self.assertIn('gs-column="12"', grid)
+        self.assertIn("{% for device in reorder_devices %}", grid)
+        self.assertIn('gs-w="{{ device.grid_width }}"', grid)
+        self.assertIn('gs-x="{{ device.grid_x }}"', grid)
+        self.assertIn("netbox-utilities-reorder-grid", grid)
+        self.assertIn('json_script:"netbox-utilities-reorder-rack-width-data"', page)
+        self.assertIn("netbox_utilities/reorder-rack-width.js", page)
+
+        get_template("netbox_utilities/reorder_rack.html")
+        rendered_grid = render_to_string(
+            "netbox_utilities/reorder_rack_grid.html",
+            {
+                "object": SimpleNamespace(units=[1], u_height=42),
+                "face": "front",
+                "grid_id": 0,
+                "reorder_devices": [
+                    {
+                        "id": 10,
+                        "label": "LEO-Fritzbox",
+                        "face": "front",
+                        "full_depth": False,
+                        "grid_x": 0,
+                        "grid_y": 62,
+                        "grid_width": 6,
+                        "grid_height": 2,
+                        "width": 2,
+                        "horizontal_position": 1,
+                        "color": "f0a000",
+                        "text_color": "000000",
+                        "locked": False,
+                    }
+                ],
+            },
+        )
+        self.assertIn('gs-column="12"', rendered_grid)
+        self.assertIn('gs-id="10"', rendered_grid)
+        self.assertIn("LEO-Fritzbox", rendered_grid)
+
+        stylesheet = (Path(__file__).parents[1] / "static" / "netbox_utilities" / "netbox_utilities.css").read_text(
+            encoding="utf-8"
+        )
+        self.assertIn('.netbox-utilities-reorder-grid[gs-column="12"]', stylesheet)
+        self.assertIn('.grid-stack-item[gs-w="6"] { width: 50%; }', stylesheet)
+        self.assertIn('.grid-stack-item[gs-w="12"] { width: 100%; }', stylesheet)
+        self.assertIn('.grid-stack-item[gs-x="6"] { left: 50%; }', stylesheet)
+        self.assertNotIn('.grid-stack-item[gs-w="6"] { width: 50% !important; }', stylesheet)
+
+        rendered_image_grid = render_to_string(
+            "netbox_utilities/reorder_rack_grid.html",
+            {
+                "object": SimpleNamespace(units=[1], u_height=42),
+                "face": "front",
+                "grid_id": 0,
+                "images": True,
+                "labels": False,
+                "unit_width": 220,
+                "reorder_devices": [
+                    {
+                        "id": 10,
+                        "label": "LEO-Fritzbox",
+                        "face": "front",
+                        "full_depth": False,
+                        "grid_x": 0,
+                        "grid_y": 62,
+                        "grid_width": 6,
+                        "grid_height": 2,
+                        "width": 2,
+                        "horizontal_position": 1,
+                        "color": "f0a000",
+                        "text_color": "000000",
+                        "locked": False,
+                        "front_image": "/media/device-type-images/fritzbox.png",
+                        "rear_image": None,
+                    }
+                ],
+            },
+        )
+        self.assertIn("background-image: url('/media/device-type-images/fritzbox.png')", rendered_image_grid)
+        self.assertIn("background-size: 220px", rendered_image_grid)
+        self.assertNotIn(">LEO-Fritzbox<", rendered_image_grid.replace("\n", ""))
+
+    def test_resolved_reorder_page_uses_server_side_width_view(self):
+        view_class = resolve(reverse("dcim:rack_reorder", kwargs={"pk": 3})).func.view_class
+
+        self.assertIs(view_class.get, width_aware_reorder_get)
+        self.assertEqual(view_class.get.__module__, "netbox_utilities.reorder_rack")
+
+    @patch("netbox_utilities.reorder_rack.get_reorder_rack_width_data")
+    @patch("netbox_utilities.reorder_rack.get_object_or_404")
+    @patch("netbox_utilities.reorder_rack.Device")
+    @patch("django.shortcuts.render")
+    def test_server_side_reorder_view_renders_payload_devices(
+        self,
+        render_mock,
+        device_model,
+        get_object,
+        get_width_data,
+    ):
+        from dcim.models import Rack, Site
+
+        rack = Rack(
+            pk=3,
+            name="Rack02 - Rechts",
+            site=Site(pk=1, name="AWO-MWT Leonardo Schule", slug="leonardo"),
+            u_height=42,
+        )
+        get_object.return_value = rack
+        device_model.objects.filter.return_value.exclude.return_value.select_related.return_value = []
+        get_width_data.return_value = {
+            "complete": True,
+            "unit_width": 220,
+            "devices": [
+                {
+                    "id": 10,
+                    "label": "LEO-Fritzbox",
+                    "face": "front",
+                    "full_depth": False,
+                    "grid_x": 0,
+                    "grid_y": 62,
+                    "grid_width": 6,
+                    "grid_height": 2,
+                    "width": 2,
+                    "horizontal_position": 1,
+                    "color": "f0a000",
+                    "text_color": "000000",
+                    "locked": False,
+                }
+            ],
+        }
+        request = RequestFactory().get("/dcim/racks/3/reorder/")
+        request.user = MagicMock()
+        request.user.is_authenticated = True
+        expected_response = SimpleNamespace(status_code=200)
+        render_mock.return_value = expected_response
+
+        response = width_aware_reorder_get(SimpleNamespace(), request, 3)
+
+        self.assertIs(response, expected_response)
+        template_name = render_mock.call_args.args[1]
+        context = render_mock.call_args.args[2]
+        self.assertEqual(template_name, "netbox_utilities/reorder_rack.html")
+        self.assertEqual(context["reorder_devices"][0]["label"], "LEO-Fritzbox")
+        self.assertEqual(context["reorder_devices"][0]["grid_width"], 6)
+        self.assertEqual(context["asset_version"], "0.10.3")
+        self.assertIs(context["reorder_rack_width_data"], get_width_data.return_value)
+        get_width_data.assert_called_once()
+        self.assertIs(get_width_data.call_args.kwargs["rack"], rack)
+        self.assertIsNotNone(get_width_data.call_args.kwargs["devices"])
+
+    @patch("netbox_utilities.reorder_rack.get_permission_for_model", return_value="dcim.change_device")
+    def test_view_owned_rack_data_does_not_repeat_route_or_object_filtering(self, _get_permission):
+        request = RequestFactory().get("/dcim/racks/3/reorder/")
+        request.user = MagicMock()
+        request.user.has_perm.return_value = True
+        rack = SimpleNamespace(pk=3, u_height=42, desc_units=False)
+        device = SimpleNamespace(
+            pk=334,
+            rack_id=3,
+            label="LEO-Fritzbox",
+            device_type=SimpleNamespace(
+                u_height=1,
+                is_full_depth=False,
+                front_image=None,
+                rear_image=None,
+            ),
+            role=SimpleNamespace(color="f0a000"),
+            face="front",
+            position=Decimal(11),
+            netbox_utilities_rack_placement=SimpleNamespace(width=2, horizontal_position=1),
+        )
+
+        with (
+            patch("netbox_utilities.reorder_rack.reorder_rack_width_enabled") as enabled,
+            patch("netbox.config.get_config", return_value=SimpleNamespace(RACK_ELEVATION_DEFAULT_UNIT_WIDTH=220)),
+            patch("utilities.html.foreground_color", return_value="000000"),
+        ):
+            result = get_reorder_rack_width_data(request, rack=rack, devices=[device])
+
+        enabled.assert_not_called()
+        self.assertTrue(result["complete"])
+        self.assertEqual(result["devices"][0]["id"], 334)
+        self.assertEqual(result["devices"][0]["grid_width"], 6)
+
+    @patch("netbox_utilities.reorder_rack.reorder_rack_width_enabled", return_value=True)
+    @patch("netbox_utilities.reorder_rack.Rack")
+    def test_malformed_partial_placement_fails_open(self, rack_model, _enabled):
+        request = RequestFactory().get("/dcim/racks/5/reorder/")
+        request.resolver_match = SimpleNamespace(kwargs={"pk": 5}, view_name="dcim:rack_reorder")
+        request.user = MagicMock()
+        rack_model.objects.restrict.return_value.filter.return_value.first.return_value = SimpleNamespace(pk=5)
+
+        with patch("netbox_utilities.reorder_rack.Device.objects.restrict", side_effect=AttributeError("stale")):
+            result = get_reorder_rack_width_data(request)
+
+        self.assertEqual(result["status"], "native-fallback")
+        self.assertEqual(result["devices"], [])
+        self.assertFalse(result["complete"])
+
+    @patch("netbox_utilities.reorder_rack.reorder_rack_width_enabled", return_value=True)
+    @patch("netbox_utilities.reorder_rack.get_permission_for_model", return_value="dcim.change_device")
+    @patch("netbox_utilities.reorder_rack.Device")
+    @patch("netbox_utilities.reorder_rack.Rack")
+    def test_describes_every_mounted_device_for_reorder_grid(
+        self,
+        rack_model,
+        device_model,
+        _get_permission,
+        _enabled,
+    ):
+        request = RequestFactory().get("/dcim/racks/5/reorder/?view=labels-only")
+        request.resolver_match = SimpleNamespace(kwargs={"pk": 5}, view_name="dcim:rack_reorder")
+        request.user = MagicMock()
+        request.user.has_perm.return_value = True
+        rack = SimpleNamespace(pk=5, u_height=42, desc_units=False)
+        rack_model.objects.restrict.return_value.filter.return_value.first.return_value = rack
+        placement = SimpleNamespace(width=2, horizontal_position=2)
+        device = SimpleNamespace(
+            pk=10,
+            rack_id=5,
+            name="Fritzbox",
+            label="Fritzbox",
+            virtual_chassis=None,
+            device_type=SimpleNamespace(
+                u_height=1,
+                is_full_depth=False,
+                front_image=None,
+                rear_image=None,
+            ),
+            role=SimpleNamespace(color="abcdef"),
+            face="front",
+            position=Decimal(4),
+            netbox_utilities_rack_placement=placement,
+        )
+        adjacent_device = SimpleNamespace(
+            pk=12,
+            rack_id=5,
+            name="Router",
+            label="Router",
+            virtual_chassis=None,
+            device_type=SimpleNamespace(
+                u_height=1,
+                is_full_depth=False,
+                front_image=None,
+                rear_image=None,
+            ),
+            role=SimpleNamespace(color="fedcba"),
+            face="front",
+            position=Decimal(4),
+            netbox_utilities_rack_placement=SimpleNamespace(width=2, horizontal_position=1),
+        )
+        full_width_device = SimpleNamespace(
+            pk=11,
+            rack_id=5,
+            name="Switch",
+            label="Switch",
+            virtual_chassis=None,
+            device_type=SimpleNamespace(
+                u_height=1,
+                is_full_depth=False,
+                front_image=None,
+                rear_image=None,
+            ),
+            role=SimpleNamespace(color="123456"),
+            face="front",
+            position=Decimal(5),
+            netbox_utilities_rack_placement=None,
+        )
+        device_queryset = MagicMock()
+        device_queryset.filter.return_value.select_related.return_value.order_by.return_value = [
+            device,
+            adjacent_device,
+            full_width_device,
+        ]
+        device_model.objects.restrict.return_value = device_queryset
+
+        with (
+            patch(
+                "netbox.config.get_config",
+                return_value=SimpleNamespace(RACK_ELEVATION_DEFAULT_UNIT_WIDTH=220),
+            ),
+            patch("utilities.html.foreground_color", return_value="000000"),
+        ):
+            result = get_reorder_rack_width_data(request)
+
+        self.assertEqual(result["columns"], 12)
+        self.assertEqual(result["status"], "ready")
+        self.assertEqual(result["schema_version"], 3)
+        self.assertTrue(result["complete"])
+        self.assertEqual(len(result["devices"]), 3)
+        self.assertEqual(result["devices"][0]["label"], "Fritzbox")
+        self.assertFalse(result["images"])
+        self.assertTrue(result["labels"])
+        device_queryset.filter.assert_called_once_with(
+            rack=rack,
+            position__gt=0,
+            device_type__u_height__gt=0,
+        )
+        self.assertEqual(
+            {key: result["devices"][0][key] for key in ("id", "grid_x", "grid_width", "width", "horizontal_position")},
+            {"id": 10, "grid_x": 6, "grid_width": 6, "width": 2, "horizontal_position": 2},
+        )
+        self.assertEqual(
+            {key: result["devices"][1][key] for key in ("id", "grid_x", "grid_width", "width")},
+            {"id": 12, "grid_x": 0, "grid_width": 6, "width": 2},
+        )
+        self.assertEqual(
+            {key: result["devices"][2][key] for key in ("id", "grid_x", "grid_width", "width")},
+            {"id": 11, "grid_x": 0, "grid_width": 12, "width": 1},
+        )
+        self.assertEqual(
+            [device["width_source"] for device in result["devices"]],
+            ["stored", "stored", "default"],
+        )
+
 
 class ReorderRackPatchTest(SimpleTestCase):
     def test_patches_supported_plugin_only_once(self):
         original_update = object()
 
+        def original_get(self, request, pk):
+            return self, request, pk
+
         class SaveViewSet:
             update = original_update
 
-        views = SimpleNamespace(SaveViewSet=SaveViewSet)
+        class ReorderView:
+            get = original_get
+
+        api_views = SimpleNamespace(SaveViewSet=SaveViewSet)
+        page_views = SimpleNamespace(ReorderView=ReorderView)
         plugin_config = SimpleNamespace(version="1.1.4")
 
         with (
             patch("netbox_utilities.reorder_rack.apps.is_installed", return_value=True),
             patch("netbox_utilities.reorder_rack.apps.get_app_config", return_value=plugin_config),
-            patch("netbox_utilities.reorder_rack.import_module", return_value=views),
+            patch(
+                "netbox_utilities.reorder_rack.import_module",
+                side_effect=lambda name: api_views if name.endswith("api.views") else page_views,
+            ),
         ):
             self.assertTrue(install_reorder_rack_bulk_save())
             self.assertTrue(install_reorder_rack_bulk_save())
 
         self.assertIs(SaveViewSet.update, bulk_reorder_update)
         self.assertIs(SaveViewSet._netbox_utilities_original_update, original_update)
+        self.assertIs(ReorderView.get, width_aware_reorder_get)
+        self.assertIs(ReorderView._netbox_utilities_original_get, original_get)
 
     def test_skips_unsupported_plugin_version(self):
         with (

netbox_utilities/tests/test_tenant_autofill.py

@@ -50,6 +50,17 @@ class FakeQuerySet:
 
 
 class TenantAutofillTest(SimpleTestCase):
+    def test_netbox_vlan_group_reverse_scopes_do_not_break_autofill(self):
+        from ipam.models import VLANGroup
+
+        self.assertIsNone(tenant_id_from_object(VLANGroup()))
+
+    def test_ignores_reverse_relation_managers_on_scoped_objects(self):
+        reverse_manager = SimpleNamespace()
+        vlan_group = FakeObject(site=reverse_manager, rack=reverse_manager)
+
+        self.assertIsNone(tenant_id_from_object(vlan_group))
+
     def test_finds_tenant_through_parent_relation(self):
         rack = FakeObject(tenant_id=42)
         device = FakeObject(rack=rack)

netbox_utilities/tests/test_topology_views.py

@@ -0,0 +1,285 @@
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+from django.http import HttpResponse
+from django.test import RequestFactory, SimpleTestCase
+
+from netbox_utilities.topology_views import (
+    _apply_topology_widths_to_device_tags,
+    _inject_topology_widths,
+    _topology_data_for_visible_devices,
+    _visible_topology_device_urls,
+    apply_topology_rack_widths,
+    get_topology_rack_width_data,
+    is_topology_rack_elevation_request,
+    serialize_topology_placement,
+    topology_rack_width_enabled,
+)
+
+
+class TopologyViewsRackWidthTest(SimpleTestCase):
+    def setUp(self):
+        self.request = RequestFactory().get("/plugins/netbox_topology_views/rack-elevation/?rack_id=3")
+        self.request.user = MagicMock()
+
+    def test_detects_only_topology_rack_elevation_route(self):
+        self.request.resolver_match = SimpleNamespace(view_name="plugins:netbox_topology_views:rack_elevation")
+        self.assertTrue(is_topology_rack_elevation_request(self.request))
+
+        self.request.resolver_match = SimpleNamespace(view_name="dcim:rack_list")
+        self.assertFalse(is_topology_rack_elevation_request(self.request))
+
+    def test_skips_integration_when_optional_plugin_is_missing(self):
+        self.request.resolver_match = SimpleNamespace(view_name="plugins:netbox_topology_views:rack_elevation")
+        with (
+            patch("netbox_utilities.topology_views.apps.is_installed", return_value=False),
+            patch("netbox_utilities.topology_views.get_plugin_config", return_value=True),
+        ):
+            self.assertFalse(topology_rack_width_enabled(self.request))
+
+    def test_skips_integration_when_admin_disabled_it(self):
+        self.request.resolver_match = SimpleNamespace(view_name="plugins:netbox_topology_views:rack_elevation")
+        with (
+            patch("netbox_utilities.topology_views.apps.is_installed", return_value=True),
+            patch("netbox_utilities.topology_views.get_plugin_config", return_value=False),
+        ):
+            self.assertFalse(topology_rack_width_enabled(self.request))
+
+    def test_serializes_fractional_width_geometry_and_device_url(self):
+        placement = SimpleNamespace(
+            device_id=17,
+            device=SimpleNamespace(pk=17, get_absolute_url=lambda: "/dcim/devices/17/"),
+            width=3,
+            horizontal_position=2,
+        )
+
+        self.assertEqual(
+            serialize_topology_placement(placement),
+            {
+                "device_id": 17,
+                "url": "/dcim/devices/17/",
+                "width": 3,
+                "horizontal_position": 2,
+                "left_percent": 33.33333333,
+                "width_percent": 33.33333333,
+                "width_source": "stored",
+            },
+        )
+
+    @patch("netbox_utilities.topology_views.topology_rack_width_enabled", return_value=True)
+    def test_queries_all_permitted_devices_and_infers_shared_unit_widths(self, _enabled):
+        self.request.resolver_match = SimpleNamespace(view_name="plugins:netbox_topology_views:rack_elevation")
+        rack_queryset = MagicMock()
+        rack_queryset.filter.return_value = rack_queryset
+        rack_queryset.values.return_value = "selected-rack-query"
+        rack_model = MagicMock()
+        rack_model.objects.restrict.return_value = rack_queryset
+
+        device_queryset = MagicMock()
+        selected_devices = MagicMock()
+        device_queryset.filter.return_value = selected_devices
+        device_model = MagicMock()
+        device_model.objects.restrict.return_value = device_queryset
+
+        devices = [
+            SimpleNamespace(
+                pk=17,
+                rack_id=3,
+                face="front",
+                position=11,
+                device_type=SimpleNamespace(u_height=1),
+                netbox_utilities_rack_placement=None,
+                get_absolute_url=lambda: "/dcim/devices/17/",
+            ),
+            SimpleNamespace(
+                pk=18,
+                rack_id=3,
+                face="front",
+                position=11,
+                device_type=SimpleNamespace(u_height=1),
+                netbox_utilities_rack_placement=None,
+                get_absolute_url=lambda: "/dcim/devices/18/",
+            ),
+        ]
+        selected_devices.select_related.return_value.order_by.return_value = devices
+
+        with patch.dict("sys.modules", {"dcim.models": SimpleNamespace(Device=device_model, Rack=rack_model)}):
+            result = get_topology_rack_width_data(self.request)
+
+        rack_queryset.filter.assert_called_once_with(pk__in=["3"])
+        device_queryset.filter.assert_called_once_with(
+            rack_id__in="selected-rack-query",
+            position__gt=0,
+            device_type__u_height__gt=0,
+        )
+        self.assertEqual(result["status"], "ready")
+        self.assertEqual(result["schema_version"], 3)
+        self.assertTrue(result["complete"])
+        self.assertEqual(len(result["devices"]), 2)
+        self.assertEqual(result["devices"][0]["width"], 2)
+        self.assertEqual(result["devices"][0]["horizontal_position"], 1)
+        self.assertEqual(result["devices"][1]["horizontal_position"], 2)
+        self.assertEqual(result["devices"][0]["width_source"], "inferred")
+
+    def test_frontend_supports_live_view_and_all_rack_export_formats(self):
+        script = (Path(__file__).parents[1] / "static" / "netbox_utilities" / "topology-rack-width.js").read_text(
+            encoding="utf-8"
+        )
+
+        self.assertIn("netbox-utilities-partial-width", script)
+        self.assertIn("horizontalGeometry", script)
+        self.assertIn("buildRackSvg", script)
+        self.assertIn("buildRackDrawio", script)
+        self.assertIn("format === 'svg'", script)
+        self.assertIn("format === 'drawio'", script)
+        self.assertIn("canvas.toBlob", script)
+        self.assertIn("event.stopImmediatePropagation()", script)
+        self.assertIn("rackExportCompatible", script)
+        self.assertIn("liveViewCompatible", script)
+        self.assertIn("payload?.devices", script)
+        self.assertIn("payload.status !== 'ready'", script)
+        self.assertIn("payload?.schema_version !== 3", script)
+        self.assertIn("placement.source", script)
+        self.assertLess(script.index("liveViewCompatible"), script.index("netbox-utilities-partial-width"))
+        self.assertLess(script.index("exportGraphic(graphic"), script.index("event.preventDefault()"))
+
+    @patch("netbox_utilities.topology_views.topology_rack_width_enabled", return_value=True)
+    def test_malformed_partial_placement_fails_open(self, _enabled):
+        self.request.resolver_match = SimpleNamespace(view_name="plugins:netbox_topology_views:rack_elevation")
+        with patch("dcim.models.Rack.objects.restrict", side_effect=AttributeError("stale")):
+            result = get_topology_rack_width_data(self.request)
+
+        self.assertEqual(result["status"], "native-fallback")
+        self.assertEqual(result["devices"], [])
+        self.assertFalse(result["complete"])
+
+    def test_partial_width_css_uses_topology_device_slot_geometry(self):
+        stylesheet = (Path(__file__).parents[1] / "static" / "netbox_utilities" / "netbox_utilities.css").read_text(
+            encoding="utf-8"
+        )
+
+        self.assertIn(".rack-device.netbox-utilities-partial-width", stylesheet)
+        self.assertIn("--netbox-utilities-rack-device-left", stylesheet)
+        self.assertIn("--netbox-utilities-rack-device-width", stylesheet)
+
+    def test_extracts_only_devices_rendered_by_the_authorized_topology_view(self):
+        html = """
+        <a class="rack-device" href="/dcim/devices/334/">Fritzbox</a>
+        <a class="rack-device active" href="/dcim/devices/340/">Grandstream</a>
+        <a href="/dcim/devices/999/">Not a rack device</a>
+        """
+
+        self.assertEqual(
+            _visible_topology_device_urls(html),
+            {334: "/dcim/devices/334/", 340: "/dcim/devices/340/"},
+        )
+
+    @patch("dcim.models.Device")
+    def test_builds_both_stored_half_widths_from_visible_he11_devices(self, device_model):
+        devices = [
+            SimpleNamespace(
+                pk=334,
+                rack_id=3,
+                face="front",
+                position=11,
+                device_type=SimpleNamespace(u_height=1),
+                netbox_utilities_rack_placement=SimpleNamespace(width=2, horizontal_position=1),
+                get_absolute_url=lambda: "/dcim/devices/334/",
+            ),
+            SimpleNamespace(
+                pk=340,
+                rack_id=3,
+                face="front",
+                position=11,
+                device_type=SimpleNamespace(u_height=1),
+                netbox_utilities_rack_placement=SimpleNamespace(width=2, horizontal_position=2),
+                get_absolute_url=lambda: "/dcim/devices/340/",
+            ),
+        ]
+        device_model.objects.filter.return_value.select_related.return_value.order_by.return_value = devices
+
+        result = _topology_data_for_visible_devices({334: "/dcim/devices/334/", 340: "/dcim/devices/340/"})
+
+        self.assertTrue(result["complete"])
+        self.assertEqual(
+            [(item["device_id"], item["width"], item["horizontal_position"]) for item in result["devices"]],
+            [(334, 2, 1), (340, 2, 2)],
+        )
+
+    @patch("netbox_utilities.topology_views._topology_data_for_visible_devices")
+    def test_injects_stored_widths_into_the_completed_foreign_response(self, get_data):
+        get_data.return_value = {
+            "devices": [
+                {
+                    "device_id": 334,
+                    "url": "/dcim/devices/334/",
+                    "width": 2,
+                    "horizontal_position": 1,
+                    "width_source": "stored",
+                    "left_percent": 0,
+                    "width_percent": 50,
+                },
+                {
+                    "device_id": 340,
+                    "url": "/dcim/devices/340/",
+                    "width": 2,
+                    "horizontal_position": 2,
+                    "width_source": "stored",
+                    "left_percent": 50,
+                    "width_percent": 50,
+                },
+            ],
+            "status": "ready",
+            "schema_version": 3,
+            "complete": True,
+        }
+        response = HttpResponse(
+            '<html><head></head><body><a class="rack-device" href="/dcim/devices/334/">A</a>'
+            '<a class="rack-device" href="/dcim/devices/340/">B</a></body></html>'
+        )
+
+        result = _inject_topology_widths(response)
+        html = result.content.decode()
+
+        get_data.assert_called_once_with({334: "/dcim/devices/334/", 340: "/dcim/devices/340/"})
+        self.assertIn('id="netbox-utilities-topology-rack-width-styles"', html)
+        self.assertIn('.rack-device[href="/dcim/devices/334/"]', html)
+        self.assertIn("left: calc(50% + 3px) !important", html)
+        self.assertIn("netbox_utilities/topology-rack-width.js?v=0.10.3", html)
+        self.assertIn("left:calc(0% + 3px)!important", html)
+        self.assertIn("left:calc(50% + 3px)!important", html)
+        self.assertIn("width:calc(50% - 6px)!important", html)
+
+    def test_preserves_existing_topology_style_while_applying_width(self):
+        data = {
+            "devices": [
+                {
+                    "url": "/dcim/devices/334/",
+                    "left_percent": 0,
+                    "width_percent": 50,
+                }
+            ]
+        }
+        html = (
+            '<a class="rack-device" href="/dcim/devices/334/" '
+            'style="bottom: 10%; height: 2%; border-color: #f00">Fritzbox</a>'
+        )
+
+        result = _apply_topology_widths_to_device_tags(html, data)
+
+        self.assertIn("bottom: 10%", result)
+        self.assertIn("height: 2%", result)
+        self.assertIn("left:calc(0% + 3px)!important", result)
+        self.assertIn("width:calc(50% - 6px)!important", result)
+
+    @patch("netbox_utilities.topology_views._inject_topology_widths")
+    @patch("netbox_utilities.topology_views.topology_rack_width_enabled", return_value=True)
+    def test_response_processor_runs_after_the_topology_view(self, _enabled, inject):
+        response = HttpResponse("<html></html>")
+        inject.return_value = response
+
+        result = apply_topology_rack_widths(self.request, response)
+
+        self.assertIs(result, response)
+        inject.assert_called_once_with(response)

netbox_utilities/topology_views.py

@@ -0,0 +1,244 @@
+import logging
+import re
+from html import unescape
+
+from django.apps import apps
+from django.core.exceptions import ObjectDoesNotExist
+from django.db import OperationalError, ProgrammingError
+from django.templatetags.static import static
+from django.utils.html import escape, json_script
+from netbox.plugins import get_plugin_config
+
+from . import __version__
+from .rack_width import effective_width_positions
+
+logger = logging.getLogger(__name__)
+
+TOPOLOGY_RACK_ELEVATION_VIEW = "plugins:netbox_topology_views:rack_elevation"
+RACK_DEVICE_TAG_RE = re.compile(
+    r"<a\b[^>]*\bclass=[\"'][^\"']*\brack-device\b[^\"']*[\"'][^>]*>",
+    re.IGNORECASE,
+)
+HREF_RE = re.compile(r"\bhref=[\"'](?P<url>[^\"']+)[\"']", re.IGNORECASE)
+STYLE_RE = re.compile(r"\bstyle=(?P<quote>[\"'])(?P<style>.*?)(?P=quote)", re.IGNORECASE)
+DEVICE_ID_RE = re.compile(r"(?:^|/)dcim/devices/(?P<device_id>\d+)/?(?:$|[?#])")
+
+
+def is_topology_rack_elevation_request(request):
+    resolver_match = getattr(request, "resolver_match", None)
+    return getattr(resolver_match, "view_name", None) == TOPOLOGY_RACK_ELEVATION_VIEW
+
+
+def topology_rack_width_enabled(request):
+    """Return whether the optional Topology Views rack integration applies."""
+    return bool(
+        is_topology_rack_elevation_request(request)
+        and get_plugin_config("netbox_utilities", "topology_views_rack_width_enabled")
+        and apps.is_installed("netbox_topology_views")
+    )
+
+
+def serialize_topology_placement(placement):
+    return serialize_topology_width(
+        placement.device,
+        placement.width,
+        placement.horizontal_position,
+        source="stored",
+    )
+
+
+def serialize_topology_width(device, width, horizontal_position, *, source):
+    width = int(width)
+    horizontal_position = int(horizontal_position)
+    return {
+        "device_id": device.pk,
+        "url": device.get_absolute_url(),
+        "width": width,
+        "horizontal_position": horizontal_position,
+        "left_percent": round((horizontal_position - 1) / width * 100, 8),
+        "width_percent": round(100 / width, 8),
+        "width_source": source,
+    }
+
+
+def get_topology_rack_width_data(request):
+    """Return permitted partial-width devices shown by Topology Views."""
+    if not topology_rack_width_enabled(request):
+        return None
+
+    data = {"devices": [], "status": "ready", "schema_version": 3, "complete": False}
+    if not request.GET:
+        return data
+
+    from dcim.models import Device, Rack
+
+    try:
+        racks = Rack.objects.restrict(request.user, "view")
+        selected_racks = request.GET.getlist("rack_id")
+        if selected_racks:
+            racks = racks.filter(pk__in=selected_racks)
+        else:
+            selected_sites = request.GET.getlist("site_id")
+            selected_locations = request.GET.getlist("location_id")
+            if selected_sites:
+                racks = racks.filter(site_id__in=selected_sites)
+            if selected_locations:
+                racks = racks.filter(location_id__in=selected_locations)
+
+        devices = list(
+            Device.objects.restrict(request.user, "view")
+            .filter(
+                rack_id__in=racks.values("pk"),
+                position__gt=0,
+                device_type__u_height__gt=0,
+            )
+            .select_related("device_type", "netbox_utilities_rack_placement")
+            .order_by("rack_id", "face", "position", "pk")
+        )
+        widths = effective_width_positions(devices)
+        data["devices"] = [
+            serialize_topology_width(device, width, position, source=source)
+            for device in devices
+            for width, position, source in (widths[device.pk],)
+            if width > 1
+        ]
+        data["complete"] = True
+        return data
+    except (
+        AttributeError,
+        ObjectDoesNotExist,
+        OperationalError,
+        ProgrammingError,
+        TypeError,
+        ValueError,
+    ):
+        # Keep NetBox usable while plugin migrations are being installed.
+        logger.warning(
+            "Could not load partial rack widths for NetBox Topology Views path %s; using its native rack layout",
+            request.get_full_path(),
+            exc_info=True,
+        )
+        data["status"] = "native-fallback"
+        return data
+
+
+def _visible_topology_device_urls(html):
+    """Return device URLs which the authorized Topology response actually contains."""
+    urls = {}
+    for tag_match in RACK_DEVICE_TAG_RE.finditer(html):
+        href_match = HREF_RE.search(tag_match.group(0))
+        if href_match is None:
+            continue
+        url = unescape(href_match.group("url"))
+        device_match = DEVICE_ID_RE.search(url)
+        if device_match is not None:
+            urls[int(device_match.group("device_id"))] = url
+    return urls
+
+
+def _topology_data_for_visible_devices(visible_urls):
+    """Build widths only for devices already exposed by the foreign view."""
+    from dcim.models import Device
+
+    devices = list(
+        Device.objects.filter(pk__in=visible_urls)
+        .select_related("device_type", "netbox_utilities_rack_placement")
+        .order_by("rack_id", "face", "position", "pk")
+    )
+    widths = effective_width_positions(devices)
+    result = {"devices": [], "status": "ready", "schema_version": 3, "complete": True}
+    for device in devices:
+        width, position, source = widths[device.pk]
+        if width <= 1:
+            continue
+        descriptor = serialize_topology_width(device, width, position, source=source)
+        descriptor["url"] = visible_urls[device.pk]
+        result["devices"].append(descriptor)
+    return result
+
+
+def _css_string(value):
+    return str(value).replace("\\", "\\\\").replace('"', '\\"').replace("\n", "\\a ")
+
+
+def _topology_width_head(data):
+    rules = []
+    for device in data["devices"]:
+        rules.append(
+            f'.rack-device[href="{_css_string(device["url"])}"] {{'
+            " right: auto !important;"
+            f" left: calc({device['left_percent']}% + 3px) !important;"
+            f" width: calc({device['width_percent']}% - 6px) !important;"
+            " }"
+        )
+    stylesheet = f'<style id="netbox-utilities-topology-rack-width-styles">{"".join(rules)}</style>'
+    payload = json_script(data, "netbox-utilities-topology-rack-width-data")
+    script_url = escape(f"{static('netbox_utilities/topology-rack-width.js')}?v={__version__}")
+    return f'{stylesheet}{payload}<script src="{script_url}" defer></script>'
+
+
+def _apply_topology_widths_to_device_tags(html, data):
+    descriptors = {device["url"]: device for device in data["devices"]}
+
+    def replace_tag(match):
+        tag = match.group(0)
+        href_match = HREF_RE.search(tag)
+        if href_match is None:
+            return tag
+        descriptor = descriptors.get(unescape(href_match.group("url")))
+        if descriptor is None:
+            return tag
+
+        geometry = (
+            "right:auto!important;"
+            f"left:calc({descriptor['left_percent']}% + 3px)!important;"
+            f"width:calc({descriptor['width_percent']}% - 6px)!important"
+        )
+        style_match = STYLE_RE.search(tag)
+        if style_match is not None:
+            quote = style_match.group("quote")
+            existing = style_match.group("style").rstrip().rstrip(";")
+            replacement = f"style={quote}{existing};{geometry}{quote}"
+            return f"{tag[: style_match.start()]}{replacement}{tag[style_match.end() :]}"
+        return f'{tag[:-1]} style="{geometry}">'
+
+    return RACK_DEVICE_TAG_RE.sub(replace_tag, html)
+
+
+def _inject_topology_widths(response):
+    if (
+        getattr(response, "streaming", False)
+        or getattr(response, "status_code", None) != 200
+        or "text/html" not in response.get("Content-Type", "")
+    ):
+        return response
+
+    html = response.content.decode(response.charset or "utf-8")
+    if "</head>" not in html.lower() or "netbox-utilities-topology-rack-width-data" in html:
+        return response
+    visible_urls = _visible_topology_device_urls(html)
+    data = _topology_data_for_visible_devices(visible_urls)
+    html = _apply_topology_widths_to_device_tags(html, data)
+    insertion = _topology_width_head(data)
+    head_end = html.lower().index("</head>")
+    html = f"{html[:head_end]}{insertion}{html[head_end:]}"
+    content = html.encode(response.charset or "utf-8")
+    response.content = content
+    if response.has_header("Content-Length"):
+        response["Content-Length"] = str(len(content))
+    return response
+
+
+def apply_topology_rack_widths(request, response):
+    """Apply widths after the optional view has rendered its authorized devices."""
+    if not topology_rack_width_enabled(request):
+        return response
+    try:
+        return _inject_topology_widths(response)
+    except Exception:
+        logger.warning(
+            "Could not inject partial rack widths into NetBox Topology Views path %s",
+            request.get_full_path(),
+            exc_info=True,
+        )
+        return response

pyproject.toml

@@ -4,8 +4,8 @@ build-backend = "hatchling.build"
 
 [project]
 name = "netbox-utilities"
-version = "0.7.2"
-description = "Navigation, tenant utilities, patchpanel mapping, bulk uploads, and atomic rack reordering for NetBox 4.6"
+version = "0.10.3"
+description = "Navigation, tenant utilities, connection VLANs, partial-width racks, and bulk operations for NetBox 4.6"
 readme = "README.md"
 requires-python = ">=3.12"
 license = { text = "MIT" }