✨(backend) add Traefik reverse proxy support for media-auth

Adds support for serving media behind Traefik, which currently cannot work
at all.

The media-auth subrequest views read the original request URL from a
hardcoded HTTP_X_ORIGINAL_URL header. That header is an nginx-ingress
convention. Traefik's ForwardAuth middleware sends X-Forwarded-Uri instead
and has no mechanism to emit X-Original-URL, so behind Traefik every
recording download and file attachment is rejected with a bare 403 --
indistinguishable from a legitimate permission denial, which makes it
painful to diagnose.

Add MEDIA_AUTH_ORIGINAL_URL_HEADER, defaulting to HTTP_X_ORIGINAL_URL so
existing nginx-ingress deployments are unaffected. Traefik deployments set
it to HTTP_X_FORWARDED_URI. It is used in both places that resolve the
header: RecordingViewSet._auth_get_original_url and the file attachment
_authorize_subrequest. The log message on a missing header now names the
header actually expected, which is what makes the failure diagnosable.

This mirrors the setting the sibling Docs project already exposes
(suitenumerique/docs, MEDIA_AUTH_ORIGINAL_URL_HEADER) for the same reason.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to
 ### Added
 
 - ✨(frontend) add 1080p sending resolution option #1660
+- ✨(backend) add Traefik support via configurable media-auth url header #1649
 
 ### Fixed
 

src/backend/core/api/viewsets.py

@@ -1076,9 +1076,10 @@ class RecordingViewSet(
 
     def _auth_get_original_url(self, request):
         """
-        Extracts and parses the original URL from the "HTTP_X_ORIGINAL_URL" header.
+        Extracts and parses the original URL from the configured header.
         Raises PermissionDenied if the header is missing.
-        The original url is passed by nginx in the "HTTP_X_ORIGINAL_URL" header.
+        The original url is passed by the reverse proxy in the header named by the
+        MEDIA_AUTH_ORIGINAL_URL_HEADER setting, which defaults to "HTTP_X_ORIGINAL_URL".
         See corresponding ingress configuration in Helm chart and read about the
         nginx.ingress.kubernetes.io/auth-url annotation to understand how the Nginx ingress
         is configured to do this.
@@ -1088,9 +1089,13 @@ class RecordingViewSet(
         reasons.
         """
         # Extract the original URL from the request header
-        original_url = request.META.get("HTTP_X_ORIGINAL_URL")
+        original_url = request.META.get(settings.MEDIA_AUTH_ORIGINAL_URL_HEADER)
         if not original_url:
-            logger.warning("Missing HTTP_X_ORIGINAL_URL header in subrequest")
+            logger.warning(
+                "Missing %s header in subrequest. Set MEDIA_AUTH_ORIGINAL_URL_HEADER "
+                "to the header your reverse proxy sends.",
+                settings.MEDIA_AUTH_ORIGINAL_URL_HEADER,
+            )
             raise drf_exceptions.PermissionDenied()
 
         logger.debug("Original url: '%s'", original_url)
@@ -1415,7 +1420,8 @@ class FileViewSet(
         Authorize access based on the original URL of an Nginx subrequest
         and user permissions. Returns a dictionary of URL parameters if authorized.
 
-        The original url is passed by nginx in the "HTTP_X_ORIGINAL_URL" header.
+        The original url is passed by the reverse proxy in the header named by the
+        MEDIA_AUTH_ORIGINAL_URL_HEADER setting, which defaults to "HTTP_X_ORIGINAL_URL".
         See corresponding ingress configuration in Helm chart and read about the
         nginx.ingress.kubernetes.io/auth-url annotation to understand how the Nginx ingress
         is configured to do this.
@@ -1434,9 +1440,13 @@ class FileViewSet(
         - PermissionDenied if authorization fails.
         """
         # Extract the original URL from the request header
-        original_url = request.META.get("HTTP_X_ORIGINAL_URL")
+        original_url = request.META.get(settings.MEDIA_AUTH_ORIGINAL_URL_HEADER)
         if not original_url:
-            logger.warning("Missing HTTP_X_ORIGINAL_URL header in subrequest")
+            logger.warning(
+                "Missing %s header in subrequest. Set MEDIA_AUTH_ORIGINAL_URL_HEADER "
+                "to the header your reverse proxy sends.",
+                settings.MEDIA_AUTH_ORIGINAL_URL_HEADER,
+            )
             raise drf_exceptions.PermissionDenied()
 
         parsed_url = urlparse(original_url)

src/backend/core/tests/files/test_api_files_media_auth.py

@@ -7,6 +7,7 @@ from urllib.parse import quote, urlparse
 
 from django.conf import settings
 from django.core.files.storage import default_storage
+from django.test import override_settings
 from django.utils import timezone
 
 import pytest
@@ -143,3 +144,59 @@ def test_api_files_media_auth_own_file_deleted():
     )
 
     assert response.status_code == 403
+
+
+@override_settings(MEDIA_AUTH_ORIGINAL_URL_HEADER="HTTP_X_FORWARDED_URI")
+def test_api_files_media_auth_custom_original_url_header():
+    """
+    Authorization should honour the configured original-url header.
+
+    Covers the attachment subrequest path, which resolves the header separately
+    from the recording one. Reverse proxies other than nginx-ingress use
+    different headers: Traefik's ForwardAuth sends X-Forwarded-Uri and cannot
+    emit X-Original-URL at all.
+    """
+    user = factories.UserFactory()
+
+    file = factories.FileFactory(
+        type=models.FileTypeChoices.BACKGROUND_IMAGE,
+        update_upload_state=models.FileUploadStateChoices.READY,
+        creator=user,
+    )
+
+    client = APIClient()
+    client.force_login(user)
+
+    default_storage.save(file.file_key, BytesIO(b"my prose"))
+
+    original_url = f"http://localhost/media/{file.file_key:s}"
+    response = client.get(
+        "/api/v1.0/files/media-auth/", HTTP_X_FORWARDED_URI=original_url
+    )
+
+    assert response.status_code == 200
+    assert "AWS4-HMAC-SHA256 Credential=" in response["Authorization"]
+
+
+@override_settings(MEDIA_AUTH_ORIGINAL_URL_HEADER="HTTP_X_FORWARDED_URI")
+def test_api_files_media_auth_default_header_ignored_when_reconfigured():
+    """
+    Only the configured header should be honoured, never a hardcoded fallback.
+    """
+    user = factories.UserFactory()
+
+    file = factories.FileFactory(
+        type=models.FileTypeChoices.BACKGROUND_IMAGE,
+        update_upload_state=models.FileUploadStateChoices.READY,
+        creator=user,
+    )
+
+    client = APIClient()
+    client.force_login(user)
+
+    original_url = f"http://localhost/media/{file.file_key:s}"
+    response = client.get(
+        "/api/v1.0/files/media-auth/", HTTP_X_ORIGINAL_URL=original_url
+    )
+
+    assert response.status_code == 403

src/backend/core/tests/recording/test_api_recordings_media_auth.py

@@ -8,6 +8,7 @@ from uuid import uuid4
 
 from django.conf import settings
 from django.core.files.storage import default_storage
+from django.test import override_settings
 from django.utils import timezone
 
 import pytest
@@ -282,3 +283,63 @@ def test_api_recordings_media_auth_success_administrator(mode):
         timeout=1,
     )
     assert response.content.decode("utf-8") == "my prose"
+
+
+def test_api_recordings_media_auth_missing_header():
+    """
+    Test that a subrequest without the configured original-url header is rejected.
+    """
+    user = UserFactory()
+
+    client = APIClient()
+    client.force_login(user)
+
+    response = client.get("/api/v1.0/recordings/media-auth/")
+
+    assert response.status_code == 403
+
+
+@override_settings(MEDIA_AUTH_ORIGINAL_URL_HEADER="HTTP_X_FORWARDED_URI")
+def test_api_recordings_media_auth_custom_original_url_header():
+    """
+    Test that the header carrying the original URL can be configured.
+
+    Reverse proxies other than nginx-ingress use different headers: Traefik's
+    ForwardAuth sends X-Forwarded-Uri and cannot emit X-Original-URL at all.
+    """
+    user = UserFactory()
+
+    client = APIClient()
+    client.force_login(user)
+
+    original_url = f"http://localhost/media/recordings/{uuid4()!s}.mp4"
+
+    response = client.get(
+        "/api/v1.0/recordings/media-auth/", HTTP_X_FORWARDED_URI=original_url
+    )
+
+    # The header was read and parsed: we get as far as looking the recording up,
+    # rather than being rejected for a missing header.
+    assert response.status_code == 404
+
+
+@override_settings(MEDIA_AUTH_ORIGINAL_URL_HEADER="HTTP_X_FORWARDED_URI")
+def test_api_recordings_media_auth_default_header_ignored_when_reconfigured():
+    """
+    Test that only the configured header is honoured.
+
+    Guards against the header being read from a hardcoded name in parallel with
+    the setting.
+    """
+    user = UserFactory()
+
+    client = APIClient()
+    client.force_login(user)
+
+    original_url = f"http://localhost/media/recordings/{uuid4()!s}.mp4"
+
+    response = client.get(
+        "/api/v1.0/recordings/media-auth/", HTTP_X_ORIGINAL_URL=original_url
+    )
+
+    assert response.status_code == 403

src/backend/meet/settings.py

@@ -129,6 +129,15 @@ class Base(Configuration):
     MEDIA_BASE_URL = values.Value(
         "", environ_name="MEDIA_BASE_URL", environ_prefix=None
     )
+    # Header the reverse proxy uses to pass the original request URL to the
+    # media-auth subrequest views. nginx-ingress sends X-Original-URL, which is
+    # the default. Other proxies use different headers -- Traefik's ForwardAuth,
+    # for instance, sends X-Forwarded-Uri and cannot emit X-Original-URL at all.
+    MEDIA_AUTH_ORIGINAL_URL_HEADER = values.Value(
+        default="HTTP_X_ORIGINAL_URL",
+        environ_name="MEDIA_AUTH_ORIGINAL_URL_HEADER",
+        environ_prefix=None,
+    )
 
     SITE_ID = 1