From a4c5e4a6451dfc7b378c10b916635de6bdafa80a Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 Jan 2018 11:06:42 +0000
Subject: [PATCH 01/10] Fix thumbnailing remote files

---
 synapse/rest/media/v1/media_repository.py   | 28 +++++++++++++++++++++
 synapse/rest/media/v1/thumbnail_resource.py |  4 +--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 45bc534200..2608fab5de 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -227,6 +227,34 @@ class MediaRepository(object):
         else:
             respond_404(request)
 
+    @defer.inlineCallbacks
+    def get_remote_media_info(self, server_name, media_id):
+        """Gets the media info associated with the remote file, downloading
+        if necessary.
+
+        Args:
+            server_name (str): Remote server_name where the media originated.
+            media_id (str): The media ID of the content (as defined by the
+                remote server).
+
+        Returns:
+            Deferred[dict]: The media_info of the file
+        """
+        # We linearize here to ensure that we don't try and download remote
+        # media multiple times concurrently
+        key = (server_name, media_id)
+        with (yield self.remote_media_linearizer.queue(key)):
+            responder, media_info = yield self._get_remote_media_impl(
+                server_name, media_id,
+            )
+
+        # Ensure we actually use the responder so that it releases resources
+        if responder:
+            with responder:
+                pass
+
+        defer.returnValue(media_info)
+
     @defer.inlineCallbacks
     def _get_remote_media_impl(self, server_name, media_id):
         """Looks for media in local cache, if not there then attempt to
diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index 835540c3dd..70cea7782e 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -165,7 +165,7 @@ class ThumbnailResource(Resource):
     def _select_or_generate_remote_thumbnail(self, request, server_name, media_id,
                                              desired_width, desired_height,
                                              desired_method, desired_type):
-        media_info = yield self.media_repo.get_remote_media(server_name, media_id)
+        media_info = yield self.media_repo.get_remote_media_info(server_name, media_id)
 
         thumbnail_infos = yield self.store.get_remote_media_thumbnails(
             server_name, media_id,
@@ -216,7 +216,7 @@ class ThumbnailResource(Resource):
         # TODO: Don't download the whole remote file
         # We should proxy the thumbnail from the remote server instead of
         # downloading the remote file and generating our own thumbnails.
-        yield self.media_repo.get_remote_media(server_name, media_id)
+        yield self.media_repo.get_remote_media_info(server_name, media_id)
 
         thumbnail_infos = yield self.store.get_remote_media_thumbnails(
             server_name, media_id,

From c5b589f2e8205ca0253534cf5826b807253bb8ea Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 Jan 2018 12:01:40 +0000
Subject: [PATCH 02/10] Log when we respond with 404

---
 synapse/rest/media/v1/media_repository.py   | 1 +
 synapse/rest/media/v1/thumbnail_resource.py | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 2608fab5de..b12fabd943 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -285,6 +285,7 @@ class MediaRepository(object):
         # If we have an entry in the DB, try and look for it
         if media_info:
             if media_info["quarantined_by"]:
+                logger.info("Media is quarentined")
                 raise NotFoundError()
 
             responder = yield self.media_storage.fetch_media(file_info)
diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index 70cea7782e..b8c38eb319 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -85,6 +85,7 @@ class ThumbnailResource(Resource):
         media_info = yield self.store.get_local_media(media_id)
 
         if not media_info or media_info["quarantined_by"]:
+            logger.info("Media is quarantined")
             respond_404(request)
             return
 
@@ -111,6 +112,7 @@ class ThumbnailResource(Resource):
             responder = yield self.media_storage.fetch_media(file_info)
             yield respond_with_responder(request, responder, t_type, t_length)
         else:
+            logger.info("Couldn't find any generated thumbnails")
             respond_404(request)
 
     @defer.inlineCallbacks
@@ -120,6 +122,7 @@ class ThumbnailResource(Resource):
         media_info = yield self.store.get_local_media(media_id)
 
         if not media_info or media_info["quarantined_by"]:
+            logger.info("Media is quarantined")
             respond_404(request)
             return
 
@@ -159,6 +162,7 @@ class ThumbnailResource(Resource):
         if file_path:
             yield respond_with_file(request, desired_type, file_path)
         else:
+            logger.warn("Failed to generate local thumbnail")
             respond_404(request)
 
     @defer.inlineCallbacks
@@ -197,7 +201,7 @@ class ThumbnailResource(Resource):
                     yield respond_with_responder(request, responder, t_type, t_length)
                     return
 
-        logger.debug("We don't have a local thumbnail of that size. Generating")
+        logger.debug("We don't have a remote thumbnail of that size. Generating")
 
         # Okay, so we generate one.
         file_path = yield self.media_repo.generate_remote_exact_thumbnail(
@@ -208,6 +212,7 @@ class ThumbnailResource(Resource):
         if file_path:
             yield respond_with_file(request, desired_type, file_path)
         else:
+            logger.warn("Failed to generate remote thumbnail")
             respond_404(request)
 
     @defer.inlineCallbacks
@@ -241,6 +246,7 @@ class ThumbnailResource(Resource):
             responder = yield self.media_storage.fetch_media(file_info)
             yield respond_with_responder(request, responder, t_type, t_length)
         else:
+            logger.info("Failed to find any generated thumbnails")
             respond_404(request)
 
     def _select_thumbnail(self, desired_width, desired_height, desired_method,

From 9795b9ebb11953747e6362fe123725326885667b Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 Jan 2018 12:02:06 +0000
Subject: [PATCH 03/10] Correctly use server_name/file_id when
 generating/fetching remote thumbnails

---
 synapse/rest/media/v1/media_repository.py   | 7 +++++--
 synapse/rest/media/v1/thumbnail_resource.py | 6 +++---
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index b12fabd943..e82dcfdc2c 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -539,7 +539,10 @@ class MediaRepository(object):
             Deferred[dict]: Dict with "width" and "height" keys of original image
         """
         media_type = media_info["media_type"]
-        file_id = media_info.get("filesystem_id")
+        if server_name:
+            file_id = media_info["filesystem_id"]
+        else:
+            file_id = media_id
         requirements = self._get_thumbnail_requirements(media_type)
         if not requirements:
             return
@@ -597,7 +600,7 @@ class MediaRepository(object):
             try:
                 file_info = FileInfo(
                     server_name=server_name,
-                    file_id=media_id,
+                    file_id=file_id,
                     thumbnail=True,
                     thumbnail_width=t_width,
                     thumbnail_height=t_height,
diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index b8c38eb319..e20d6f10b0 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -185,7 +185,7 @@ class ThumbnailResource(Resource):
 
             if t_w and t_h and t_method and t_type:
                 file_info = FileInfo(
-                    server_name=None, file_id=media_id,
+                    server_name=server_name, file_id=media_info["filesystem_id"],
                     thumbnail=True,
                     thumbnail_width=info["thumbnail_width"],
                     thumbnail_height=info["thumbnail_height"],
@@ -221,7 +221,7 @@ class ThumbnailResource(Resource):
         # TODO: Don't download the whole remote file
         # We should proxy the thumbnail from the remote server instead of
         # downloading the remote file and generating our own thumbnails.
-        yield self.media_repo.get_remote_media_info(server_name, media_id)
+        media_info = yield self.media_repo.get_remote_media_info(server_name, media_id)
 
         thumbnail_infos = yield self.store.get_remote_media_thumbnails(
             server_name, media_id,
@@ -232,7 +232,7 @@ class ThumbnailResource(Resource):
                 width, height, method, m_type, thumbnail_infos
             )
             file_info = FileInfo(
-                server_name=None, file_id=media_id,
+                server_name=server_name, file_id=media_info["filesystem_id"],
                 thumbnail=True,
                 thumbnail_width=thumbnail_info["thumbnail_width"],
                 thumbnail_height=thumbnail_info["thumbnail_height"],

From 307f88dfb6c157ee2bda6f9b8b3dee82cad490aa Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 Jan 2018 13:53:43 +0000
Subject: [PATCH 04/10] Fix up log lines

---
 synapse/rest/media/v1/media_repository.py   |  2 +-
 synapse/rest/media/v1/thumbnail_resource.py | 15 +++++++++------
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index e82dcfdc2c..d191f9d2f5 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -285,7 +285,7 @@ class MediaRepository(object):
         # If we have an entry in the DB, try and look for it
         if media_info:
             if media_info["quarantined_by"]:
-                logger.info("Media is quarentined")
+                logger.info("Media is quarantined")
                 raise NotFoundError()
 
             responder = yield self.media_storage.fetch_media(file_info)
diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index e20d6f10b0..1451f6f106 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -85,7 +85,9 @@ class ThumbnailResource(Resource):
         media_info = yield self.store.get_local_media(media_id)
 
         if not media_info or media_info["quarantined_by"]:
-            logger.info("Media is quarantined")
+            if media_info:
+                logger.info("Media is quarantined")
+
             respond_404(request)
             return
 
@@ -122,7 +124,8 @@ class ThumbnailResource(Resource):
         media_info = yield self.store.get_local_media(media_id)
 
         if not media_info or media_info["quarantined_by"]:
-            logger.info("Media is quarantined")
+            if media_info["quarantined_by"]:
+                logger.info("Media is quarantined")
             respond_404(request)
             return
 
@@ -152,7 +155,7 @@ class ThumbnailResource(Resource):
                     yield respond_with_responder(request, responder, t_type, t_length)
                     return
 
-        logger.debug("We don't have a local thumbnail of that size. Generating")
+        logger.debug("We don't have a thumbnail of that size. Generating")
 
         # Okay, so we generate one.
         file_path = yield self.media_repo.generate_local_exact_thumbnail(
@@ -162,7 +165,7 @@ class ThumbnailResource(Resource):
         if file_path:
             yield respond_with_file(request, desired_type, file_path)
         else:
-            logger.warn("Failed to generate local thumbnail")
+            logger.warn("Failed to generate thumbnail")
             respond_404(request)
 
     @defer.inlineCallbacks
@@ -201,7 +204,7 @@ class ThumbnailResource(Resource):
                     yield respond_with_responder(request, responder, t_type, t_length)
                     return
 
-        logger.debug("We don't have a remote thumbnail of that size. Generating")
+        logger.debug("We don't have a thumbnail of that size. Generating")
 
         # Okay, so we generate one.
         file_path = yield self.media_repo.generate_remote_exact_thumbnail(
@@ -212,7 +215,7 @@ class ThumbnailResource(Resource):
         if file_path:
             yield respond_with_file(request, desired_type, file_path)
         else:
-            logger.warn("Failed to generate remote thumbnail")
+            logger.warn("Failed to generate thumbnail")
             respond_404(request)
 
     @defer.inlineCallbacks

From 5dfc83704b9f338c975a03bad7854218658b3a80 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 Jan 2018 14:32:56 +0000
Subject: [PATCH 05/10] Fix typo

---
 synapse/rest/media/v1/thumbnail_resource.py | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index 1451f6f106..8c9653843b 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -84,10 +84,11 @@ class ThumbnailResource(Resource):
                                  method, m_type):
         media_info = yield self.store.get_local_media(media_id)
 
-        if not media_info or media_info["quarantined_by"]:
-            if media_info:
-                logger.info("Media is quarantined")
-
+        if not media_info:
+            respond_404(request)
+            return
+        if media_info["quarantined_by"]:
+            logger.info("Media is quarantined")
             respond_404(request)
             return
 
@@ -123,9 +124,11 @@ class ThumbnailResource(Resource):
                                             desired_type):
         media_info = yield self.store.get_local_media(media_id)
 
-        if not media_info or media_info["quarantined_by"]:
-            if media_info["quarantined_by"]:
-                logger.info("Media is quarantined")
+        if not media_info:
+            respond_404(request)
+            return
+        if media_info["quarantined_by"]:
+            logger.info("Media is quarantined")
             respond_404(request)
             return
 

From 0a90d9ede4a39d720afd131866f98b51aa591cf7 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 Jan 2018 16:03:05 +0000
Subject: [PATCH 06/10] Move setting of file_id up to caller

---
 synapse/rest/media/v1/media_repository.py     | 21 +++++++++----------
 synapse/rest/media/v1/preview_url_resource.py |  6 ++++--
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index d191f9d2f5..35c1dcbc97 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -151,7 +151,7 @@ class MediaRepository(object):
             "media_length": content_length,
         }
 
-        yield self._generate_thumbnails(None, media_id, media_info)
+        yield self._generate_thumbnails(None, media_id, media_id, media_info)
 
         defer.returnValue("mxc://%s/%s" % (self.server_name, media_id))
 
@@ -413,7 +413,7 @@ class MediaRepository(object):
         }
 
         yield self._generate_thumbnails(
-            server_name, media_id, media_info
+            server_name, media_id, file_id, media_info,
         )
 
         defer.returnValue(media_info)
@@ -525,24 +525,23 @@ class MediaRepository(object):
             defer.returnValue(output_path)
 
     @defer.inlineCallbacks
-    def _generate_thumbnails(self, server_name, media_id, media_info, url_cache=False):
+    def _generate_thumbnails(self, server_name, media_id, file_id, media_info,
+                             url_cache=False):
         """Generate and store thumbnails for an image.
 
         Args:
-            server_name(str|None): The server name if remote media, else None if local
-            media_id(str)
-            media_info(dict)
-            url_cache(bool): If we are thumbnailing images downloaded for the URL cache,
+            server_name (str|None): The server name if remote media, else None if local
+            media_id (str): The media ID of the content. (This is the same as
+                the file_id for local content)
+            file_id (str): Local file ID
+            media_info (dict)
+            url_cache (bool): If we are thumbnailing images downloaded for the URL cache,
                 used exclusively by the url previewer
 
         Returns:
             Deferred[dict]: Dict with "width" and "height" keys of original image
         """
         media_type = media_info["media_type"]
-        if server_name:
-            file_id = media_info["filesystem_id"]
-        else:
-            file_id = media_id
         requirements = self._get_thumbnail_requirements(media_type)
         if not requirements:
             return
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index f3dbbb3fec..5ddf581bd2 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -185,8 +185,9 @@ class PreviewUrlResource(Resource):
         logger.debug("got media_info of '%s'" % media_info)
 
         if _is_media(media_info['media_type']):
+            file_id = media_info['filesystem_id']
             dims = yield self.media_repo._generate_thumbnails(
-                None, media_info['filesystem_id'], media_info, url_cache=True,
+                None, file_id, file_id, media_info, url_cache=True,
             )
 
             og = {
@@ -231,8 +232,9 @@ class PreviewUrlResource(Resource):
 
                 if _is_media(image_info['media_type']):
                     # TODO: make sure we don't choke on white-on-transparent images
+                    file_id = image_info['filesystem_id']
                     dims = yield self.media_repo._generate_thumbnails(
-                        None, image_info['filesystem_id'], image_info, url_cache=True,
+                        None, file_id, file_id, image_info, url_cache=True,
                     )
                     if dims:
                         og["og:image:width"] = dims['width']

From 6368e5c0ab39e43ee6950ba94a826c44db7d43f7 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 Jan 2018 16:17:38 +0000
Subject: [PATCH 07/10] Change _generate_thumbnails to take media_type

---
 synapse/rest/media/v1/media_repository.py     | 11 ++++++-----
 synapse/rest/media/v1/preview_url_resource.py |  6 ++++--
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 35c1dcbc97..e08cf8af46 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -151,7 +151,9 @@ class MediaRepository(object):
             "media_length": content_length,
         }
 
-        yield self._generate_thumbnails(None, media_id, media_id, media_info)
+        yield self._generate_thumbnails(
+            None, media_id, media_id, media_info["media_type"],
+        )
 
         defer.returnValue("mxc://%s/%s" % (self.server_name, media_id))
 
@@ -413,7 +415,7 @@ class MediaRepository(object):
         }
 
         yield self._generate_thumbnails(
-            server_name, media_id, file_id, media_info,
+            server_name, media_id, file_id, media_info["media_type"],
         )
 
         defer.returnValue(media_info)
@@ -525,7 +527,7 @@ class MediaRepository(object):
             defer.returnValue(output_path)
 
     @defer.inlineCallbacks
-    def _generate_thumbnails(self, server_name, media_id, file_id, media_info,
+    def _generate_thumbnails(self, server_name, media_id, file_id, media_type,
                              url_cache=False):
         """Generate and store thumbnails for an image.
 
@@ -534,14 +536,13 @@ class MediaRepository(object):
             media_id (str): The media ID of the content. (This is the same as
                 the file_id for local content)
             file_id (str): Local file ID
-            media_info (dict)
+            media_type (str)
             url_cache (bool): If we are thumbnailing images downloaded for the URL cache,
                 used exclusively by the url previewer
 
         Returns:
             Deferred[dict]: Dict with "width" and "height" keys of original image
         """
-        media_type = media_info["media_type"]
         requirements = self._get_thumbnail_requirements(media_type)
         if not requirements:
             return
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 5ddf581bd2..981f01e417 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -187,7 +187,8 @@ class PreviewUrlResource(Resource):
         if _is_media(media_info['media_type']):
             file_id = media_info['filesystem_id']
             dims = yield self.media_repo._generate_thumbnails(
-                None, file_id, file_id, media_info, url_cache=True,
+                None, file_id, file_id, media_info["media_type"],
+                url_cache=True,
             )
 
             og = {
@@ -234,7 +235,8 @@ class PreviewUrlResource(Resource):
                     # TODO: make sure we don't choke on white-on-transparent images
                     file_id = image_info['filesystem_id']
                     dims = yield self.media_repo._generate_thumbnails(
-                        None, file_id, file_id, image_info, url_cache=True,
+                        None, file_id, file_id, image_info["media_type"],
+                        url_cache=True,
                     )
                     if dims:
                         og["og:image:width"] = dims['width']

From d863f68cab9665335b1657feeab5d00724dddd95 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 Jan 2018 16:24:15 +0000
Subject: [PATCH 08/10] Use local vars

---
 synapse/rest/media/v1/media_repository.py | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index e08cf8af46..22f86781f7 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -146,13 +146,9 @@ class MediaRepository(object):
             media_length=content_length,
             user_id=auth_user,
         )
-        media_info = {
-            "media_type": media_type,
-            "media_length": content_length,
-        }
 
         yield self._generate_thumbnails(
-            None, media_id, media_id, media_info["media_type"],
+            None, media_id, media_id, media_type,
         )
 
         defer.returnValue("mxc://%s/%s" % (self.server_name, media_id))
@@ -415,7 +411,7 @@ class MediaRepository(object):
         }
 
         yield self._generate_thumbnails(
-            server_name, media_id, file_id, media_info["media_type"],
+            server_name, media_id, file_id, media_type,
         )
 
         defer.returnValue(media_info)

From 5e97ca7ee61761f6826fd1c4220877dc787d88dc Mon Sep 17 00:00:00 2001
From: Matthew Hodgson <matthew@matrix.org>
Date: Tue, 16 Jan 2018 16:52:31 +0000
Subject: [PATCH 09/10] fix typo

---
 synapse/config/tls.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/synapse/config/tls.py b/synapse/config/tls.py
index 4748f71c2f..29eb012ddb 100644
--- a/synapse/config/tls.py
+++ b/synapse/config/tls.py
@@ -96,7 +96,7 @@ class TlsConfig(Config):
         # certificates returned by this server match one of the fingerprints.
         #
         # Synapse automatically adds the fingerprint of its own certificate
-        # to the list. So if federation traffic is handle directly by synapse
+        # to the list. So if federation traffic is handled directly by synapse
         # then no modification to the list is required.
         #
         # If synapse is run behind a load balancer that handles the TLS then it

From d728c47142019da2896bba7a84ac92e9959fd7af Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Wed, 17 Jan 2018 10:06:14 +0000
Subject: [PATCH 10/10] Add docstring

---
 synapse/rest/media/v1/media_repository.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 22f86781f7..97c82c150e 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -532,7 +532,7 @@ class MediaRepository(object):
             media_id (str): The media ID of the content. (This is the same as
                 the file_id for local content)
             file_id (str): Local file ID
-            media_type (str)
+            media_type (str): The content type of the file
             url_cache (bool): If we are thumbnailing images downloaded for the URL cache,
                 used exclusively by the url previewer