Support MSC3916 by adding a federation /thumbnail endpoint and authenticated `_matrix/client/v1/media/thumbnail` endpoint (#17388)

[MSC3916](https://github.com/matrix-org/matrix-spec-proposals/pull/3916)
added the endpoints `_matrix/federation/v1/media/thumbnail` and the
authenticated `_matrix/client/v1/media/thumbnail`.

This PR implements those endpoints, along with stabilizing
`_matrix/client/v1/media/config` and
`_matrix/client/v1/media/preview_url`.

Complement tests are at
https://github.com/matrix-org/complement/pull/728

2 files changed, 43 insertions, 19 deletions

diff --git a/synapse/rest/client/media.py b/synapse/rest/client/media.py

index c0ae5dd66f..c30e3022de 100644
--- a/synapse/rest/client/media.py
+++ b/synapse/rest/client/media.py
@@ -47,7 +47,7 @@ from synapse.util.stringutils import parse_and_validate_server_name
 logger = logging.getLogger(__name__)
 
 
-class UnstablePreviewURLServlet(RestServlet):
+class PreviewURLServlet(RestServlet):
     """
     Same as `GET /_matrix/media/r0/preview_url`, this endpoint provides a generic preview API
     for URLs which outputs Open Graph (https://ogp.me/) responses (with some Matrix
@@ -65,9 +65,7 @@ class UnstablePreviewURLServlet(RestServlet):
       * Matrix cannot be used to distribute the metadata between homeservers.
     """
 
-    PATTERNS = [
-        re.compile(r"^/_matrix/client/unstable/org.matrix.msc3916/media/preview_url$")
-    ]
+    PATTERNS = [re.compile(r"^/_matrix/client/v1/media/preview_url$")]
 
     def __init__(
         self,
@@ -95,10 +93,8 @@ class UnstablePreviewURLServlet(RestServlet):
         respond_with_json_bytes(request, 200, og, send_cors=True)
 
 
-class UnstableMediaConfigResource(RestServlet):
-    PATTERNS = [
-        re.compile(r"^/_matrix/client/unstable/org.matrix.msc3916/media/config$")
-    ]
+class MediaConfigResource(RestServlet):
+    PATTERNS = [re.compile(r"^/_matrix/client/v1/media/config$")]
 
     def __init__(self, hs: "HomeServer"):
         super().__init__()
@@ -112,10 +108,10 @@ class UnstableMediaConfigResource(RestServlet):
         respond_with_json(request, 200, self.limits_dict, send_cors=True)
 
 
-class UnstableThumbnailResource(RestServlet):
+class ThumbnailResource(RestServlet):
     PATTERNS = [
         re.compile(
-            "/_matrix/client/unstable/org.matrix.msc3916/media/thumbnail/(?P<server_name>[^/]*)/(?P<media_id>[^/]*)$"
+            "/_matrix/client/v1/media/thumbnail/(?P<server_name>[^/]*)/(?P<media_id>[^/]*)$"
         )
     ]
 
@@ -159,11 +155,25 @@ class UnstableThumbnailResource(RestServlet):
         if self._is_mine_server_name(server_name):
             if self.dynamic_thumbnails:
                 await self.thumbnailer.select_or_generate_local_thumbnail(
-                    request, media_id, width, height, method, m_type, max_timeout_ms
+                    request,
+                    media_id,
+                    width,
+                    height,
+                    method,
+                    m_type,
+                    max_timeout_ms,
+                    False,
                 )
             else:
                 await self.thumbnailer.respond_local_thumbnail(
-                    request, media_id, width, height, method, m_type, max_timeout_ms
+                    request,
+                    media_id,
+                    width,
+                    height,
+                    method,
+                    m_type,
+                    max_timeout_ms,
+                    False,
                 )
             self.media_repo.mark_recently_accessed(None, media_id)
         else:
@@ -191,6 +201,7 @@ class UnstableThumbnailResource(RestServlet):
                 m_type,
                 max_timeout_ms,
                 ip_address,
+                True,
             )
             self.media_repo.mark_recently_accessed(server_name, media_id)
 
@@ -260,11 +271,9 @@ class DownloadResource(RestServlet):
 def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     media_repo = hs.get_media_repository()
     if hs.config.media.url_preview_enabled:
-        UnstablePreviewURLServlet(hs, media_repo, media_repo.media_storage).register(
+        PreviewURLServlet(hs, media_repo, media_repo.media_storage).register(
             http_server
         )
-    UnstableMediaConfigResource(hs).register(http_server)
-    UnstableThumbnailResource(hs, media_repo, media_repo.media_storage).register(
-        http_server
-    )
+    MediaConfigResource(hs).register(http_server)
+    ThumbnailResource(hs, media_repo, media_repo.media_storage).register(http_server)
     DownloadResource(hs, media_repo).register(http_server)
diff --git a/synapse/rest/media/thumbnail_resource.py b/synapse/rest/media/thumbnail_resource.py

index ce511c6dce..70354aa439 100644
--- a/synapse/rest/media/thumbnail_resource.py
+++ b/synapse/rest/media/thumbnail_resource.py
@@ -88,11 +88,25 @@ class ThumbnailResource(RestServlet):
         if self._is_mine_server_name(server_name):
             if self.dynamic_thumbnails:
                 await self.thumbnail_provider.select_or_generate_local_thumbnail(
-                    request, media_id, width, height, method, m_type, max_timeout_ms
+                    request,
+                    media_id,
+                    width,
+                    height,
+                    method,
+                    m_type,
+                    max_timeout_ms,
+                    False,
                 )
             else:
                 await self.thumbnail_provider.respond_local_thumbnail(
-                    request, media_id, width, height, method, m_type, max_timeout_ms
+                    request,
+                    media_id,
+                    width,
+                    height,
+                    method,
+                    m_type,
+                    max_timeout_ms,
+                    False,
                 )
             self.media_repo.mark_recently_accessed(None, media_id)
         else:
@@ -120,5 +134,6 @@ class ThumbnailResource(RestServlet):
                 m_type,
                 max_timeout_ms,
                 ip_address,
+                False,
             )
             self.media_repo.mark_recently_accessed(server_name, media_id)