Add /user/{user_id}/shared_rooms/ api (#7785)

* Add shared_rooms api

* Add changelog

* Add .

* Wrap response in {"rooms": }

* linting

* Add unstable_features key

* Remove options from isort that aren't part of 5.x

`-y` and `-rc` are now default behaviour and no longer exist.

`dont-skip` is no longer required

https://timothycrosley.github.io/isort/CHANGELOG/#500-penny-july-4-2020

* Update imports to make isort happy

* Add changelog

* Update tox.ini file with correct invocation

* fix linting again for isort

* Vendor prefix unstable API

* Fix to match spec

* import Codes

* import Codes

* Use FORBIDDEN

* Update changelog.d/7785.feature

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

* Implement get_shared_rooms_for_users

* a comma

* trailing whitespace

* Handle the easy feedback

* Switch to using runInteraction

* Add tests

* Feedback

* Seperate unstable endpoint from v2

* Add upgrade node

* a line

* Fix style by adding a blank line at EOF.

* Update synapse/storage/databases/main/user_directory.py

Co-authored-by: Tulir Asokan <tulir@maunium.net>

* Update synapse/storage/databases/main/user_directory.py

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

* Update UPGRADE.rst

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

* Fix UPGRADE/CHANGELOG unstable paths

unstable unstable unstable

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
Co-authored-by: Tulir Asokan <tulir@maunium.net>

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
Co-authored-by: Tulir Asokan <tulir@maunium.net>

1 files changed, 43 insertions, 1 deletions

diff --git a/synapse/storage/databases/main/user_directory.py b/synapse/storage/databases/main/user_directory.py

index c977db042e..f2f9a5799a 100644
--- a/synapse/storage/databases/main/user_directory.py
+++ b/synapse/storage/databases/main/user_directory.py
@@ -15,7 +15,7 @@
 
 import logging
 import re
-from typing import Any, Dict, Iterable, Optional, Tuple
+from typing import Any, Dict, Iterable, Optional, Set, Tuple
 
 from synapse.api.constants import EventTypes, JoinRules
 from synapse.storage.database import DatabasePool
@@ -675,6 +675,48 @@ class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
         users.update(rows)
         return list(users)
 
+    @cached()
+    async def get_shared_rooms_for_users(
+        self, user_id: str, other_user_id: str
+    ) -> Set[str]:
+        """
+        Returns the rooms that a local user shares with another local or remote user.
+
+        Args:
+            user_id: The MXID of a local user
+            other_user_id: The MXID of the other user
+
+        Returns:
+            A set of room ID's that the users share.
+        """
+
+        def _get_shared_rooms_for_users_txn(txn):
+            txn.execute(
+                """
+                SELECT p1.room_id
+                FROM users_in_public_rooms as p1
+                INNER JOIN users_in_public_rooms as p2
+                    ON p1.room_id = p2.room_id
+                    AND p1.user_id = ?
+                    AND p2.user_id = ?
+                UNION
+                SELECT room_id
+                FROM users_who_share_private_rooms
+                WHERE
+                    user_id = ?
+                    AND other_user_id = ?
+                """,
+                (user_id, other_user_id, user_id, other_user_id),
+            )
+            rows = self.db_pool.cursor_to_dict(txn)
+            return rows
+
+        rows = await self.db_pool.runInteraction(
+            "get_shared_rooms_for_users", _get_shared_rooms_for_users_txn
+        )
+
+        return {row["room_id"] for row in rows}
+
     async def get_user_directory_stream_pos(self) -> int:
         return await self.db_pool.simple_select_one_onecol(
             table="user_directory_stream_pos",