Add an admin api to delete local media. (#8519)

Related to: #6459, #3479

Add `DELETE /_synapse/admin/v1/media/<server_name>/<media_id>` to delete
a single file from server.

1 files changed, 53 insertions, 0 deletions

diff --git a/synapse/storage/databases/main/media_repository.py b/synapse/storage/databases/main/media_repository.py
index cc538c5c10..7ef5f1bf2b 100644
--- a/synapse/storage/databases/main/media_repository.py
+++ b/synapse/storage/databases/main/media_repository.py
@@ -93,6 +93,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
 
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
+        self.server_name = hs.hostname
 
     async def get_local_media(self, media_id: str) -> Optional[Dict[str, Any]]:
         """Get the metadata for a local piece of media
@@ -115,6 +116,58 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
             desc="get_local_media",
         )
 
+    async def get_local_media_before(
+        self, before_ts: int, size_gt: int, keep_profiles: bool,
+    ) -> Optional[List[str]]:
+
+        # to find files that have never been accessed (last_access_ts IS NULL)
+        # compare with `created_ts`
+        sql = """
+            SELECT media_id
+            FROM local_media_repository AS lmr
+            WHERE
+                ( last_access_ts < ?
+                OR ( created_ts < ? AND last_access_ts IS NULL ) )
+                AND media_length > ?
+        """
+
+        if keep_profiles:
+            sql_keep = """
+                AND (
+                    NOT EXISTS
+                        (SELECT 1
+                         FROM profiles
+                         WHERE profiles.avatar_url = '{media_prefix}' || lmr.media_id)
+                    AND NOT EXISTS
+                        (SELECT 1
+                         FROM groups
+                         WHERE groups.avatar_url = '{media_prefix}' || lmr.media_id)
+                    AND NOT EXISTS
+                        (SELECT 1
+                         FROM room_memberships
+                         WHERE room_memberships.avatar_url = '{media_prefix}' || lmr.media_id)
+                    AND NOT EXISTS
+                        (SELECT 1
+                         FROM user_directory
+                         WHERE user_directory.avatar_url = '{media_prefix}' || lmr.media_id)
+                    AND NOT EXISTS
+                        (SELECT 1
+                         FROM room_stats_state
+                         WHERE room_stats_state.avatar = '{media_prefix}' || lmr.media_id)
+                )
+            """.format(
+                media_prefix="mxc://%s/" % (self.server_name,),
+            )
+            sql += sql_keep
+
+        def _get_local_media_before_txn(txn):
+            txn.execute(sql, (before_ts, before_ts, size_gt))
+            return [row[0] for row in txn]
+
+        return await self.db_pool.runInteraction(
+            "get_local_media_before", _get_local_media_before_txn
+        )
+
     async def store_local_media(
         self,
         media_id,