Add delete room admin endpoint (#7613)

The Delete Room admin API allows server admins to remove rooms from server
and block these rooms.
`DELETE /_synapse/admin/v1/rooms/<room_id>`
It is a combination and improvement of "[Shutdown room](https://github.com/matrix-org/synapse/blob/develop/docs/admin_api/shutdown_room.md)" and "[Purge room](https://github.com/matrix-org/synapse/blob/develop/docs/admin_api/purge_room.md)" API.

Fixes: #6425 

It also fixes a bug in [synapse/storage/data_stores/main/room.py](synapse/storage/data_stores/main/room.py) in ` get_room_with_stats`.
It should return `None` if the room is unknown. But it returns an `IndexError`.
https://github.com/matrix-org/synapse/blob/901b1fa561e3cc661d78aa96d59802cf2078cb0d/synapse/storage/data_stores/main/room.py#L99-L105

Related to:
- #5575
- https://github.com/Awesome-Technologies/synapse-admin/issues/17

Signed-off-by: Dirk Klimpel dirk@klimpel.org

1 files changed, 94 insertions, 0 deletions

diff --git a/docs/admin_api/rooms.md b/docs/admin_api/rooms.md
index 624e7745ba..3f26adc16c 100644
--- a/docs/admin_api/rooms.md
+++ b/docs/admin_api/rooms.md
@@ -318,3 +318,97 @@ Response:
   "state_events": 93534
 }
 ```
+
+# Delete Room API
+
+The Delete Room admin API allows server admins to remove rooms from server
+and block these rooms.
+It is a combination and improvement of "[Shutdown room](shutdown_room.md)" 
+and "[Purge room](purge_room.md)" API.
+
+Shuts down a room. Moves all local users and room aliases automatically to a
+new room if `new_room_user_id` is set. Otherwise local users only
+leave the room without any information.
+
+The new room will be created with the user specified by the `new_room_user_id` parameter
+as room administrator and will contain a message explaining what happened. Users invited
+to the new room will have power level `-10` by default, and thus be unable to speak.
+
+If `block` is `True` it prevents new joins to the old room.
+
+This API will remove all trace of the old room from your database after removing
+all local users.
+Depending on the amount of history being purged a call to the API may take
+several minutes or longer.
+
+The local server will only have the power to move local user and room aliases to
+the new room. Users on other servers will be unaffected.
+
+The API is:
+
+```json
+POST /_synapse/admin/v1/rooms/<room_id>/delete
+```
+
+with a body of:
+```json
+{
+    "new_room_user_id": "@someuser:example.com",
+    "room_name": "Content Violation Notification",
+    "message": "Bad Room has been shutdown due to content violations on this server. Please review our Terms of Service.",
+    "block": true
+}
+```
+
+To use it, you will need to authenticate by providing an ``access_token`` for a
+server admin: see [README.rst](README.rst).
+
+A response body like the following is returned:
+
+```json
+{
+    "kicked_users": [
+        "@foobar:example.com"
+    ],
+    "failed_to_kick_users": [],
+    "local_aliases": [
+        "#badroom:example.com",
+        "#evilsaloon:example.com"
+    ],
+    "new_room_id": "!newroomid:example.com"
+}
+```
+
+## Parameters
+
+The following parameters should be set in the URL:
+
+* `room_id` - The ID of the room.
+
+The following JSON body parameters are available:
+
+* `new_room_user_id` - Optional. If set, a new room will be created with this user ID
+      as the creator and admin, and all users in the old room will be moved into that
+      room. If not set, no new room will be created and the users will just be removed
+      from the old room. The user ID must be on the local server, but does not necessarily
+      have to belong to a registered user.
+* `room_name` - Optional. A string representing the name of the room that new users will be
+                invited to. Defaults to `Content Violation Notification`
+* `message` - Optional. A string containing the first message that will be sent as
+              `new_room_user_id` in the new room. Ideally this will clearly convey why the
+               original room was shut down. Defaults to `Sharing illegal content on this server
+               is not permitted and rooms in violation will be blocked.`
+* `block` - Optional. If set to `true`, this room will be added to a blocking list, preventing future attempts to
+  join the room. Defaults to `false`.
+
+The JSON body must not be empty. The body must be at least `{}`.
+
+## Response
+
+The following fields are returned in the JSON response body:
+
+* `kicked_users` - An array of users (`user_id`) that were kicked.
+* `failed_to_kick_users` - An array of users (`user_id`) that that were not kicked.
+* `local_aliases` - An array of strings representing the local aliases that were migrated from
+                    the old room to the new.
+* `new_room_id` - A string representing the room ID of the new room.