fix: bind rack integrations to rendered devices

netbox_utilities/topology_views.py

@@ -1,15 +1,29 @@
 import logging
+import re
+from functools import wraps
+from html import unescape
+from importlib import import_module
 
 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"
+TOPOLOGY_VIEW_PATCH_MARKER = "_netbox_utilities_rack_width_view"
+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)
+DEVICE_ID_RE = re.compile(r"(?:^|/)dcim/devices/(?P<device_id>\d+)/?(?:$|[?#])")
 
 
 def is_topology_rack_elevation_request(request):
@@ -108,3 +122,121 @@ def get_topology_rack_width_data(request):
         )
         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 _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)
+    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 install_topology_rack_width_support():
+    """Patch the optional view and derive widths from its authorized HTML."""
+    if not (
+        apps.is_installed("netbox_topology_views")
+        and get_plugin_config("netbox_utilities", "topology_views_rack_width_enabled")
+    ):
+        return False
+
+    try:
+        topology_views = import_module("netbox_topology_views.views")
+        view = topology_views.RackElevationView
+    except (AttributeError, ImportError):
+        logger.warning("NetBox Utilities could not find the optional Topology rack elevation view")
+        return False
+
+    if getattr(view, TOPOLOGY_VIEW_PATCH_MARKER, False):
+        return True
+
+    original_get = view.get
+
+    @wraps(original_get)
+    def width_aware_topology_get(self, request, *args, **kwargs):
+        response = original_get(self, request, *args, **kwargs)
+        try:
+            return _inject_topology_widths(response)
+        except (AttributeError, ObjectDoesNotExist, OperationalError, ProgrammingError, TypeError, ValueError):
+            logger.warning(
+                "Could not inject partial rack widths into NetBox Topology Views path %s",
+                request.get_full_path(),
+                exc_info=True,
+            )
+            return response
+
+    view._netbox_utilities_original_get = original_get
+    view.get = width_aware_topology_get
+    setattr(view, TOPOLOGY_VIEW_PATCH_MARKER, True)
+    logger.info("Enabled partial rack widths for the optional Topology rack elevation view")
+    return True