Group Deletion

Overview

A group admin can permanently delete a group using the /delete command. This removes the group and all associated data from the server. All members receive a GroupDeletedEvent and clean up their local state.

sequenceDiagram
    participant A as Admin
    participant S as Server
    participant M as Members

    A->>S: POST /groups/{id}/delete
    Note right of S: Verify admin role<br>Collect all members<br>DELETE FROM groups (CASCADE)
    S-->>A: 200 OK
    S--)M: SSE: GroupDeletedEvent { group_id }<br>(to all former members including admin)

    Note over A,M: All clients:<br>Delete local MLS group state<br>Remove from room list<br>Remove from group mapping

Steps

1. Admin verification: The server verifies the caller is an admin of the group.

2. Collect members: The server collects all group members before deletion for SSE notification targeting.

3. Delete group: The server executes DELETE FROM groups WHERE id = ?. CASCADE handles all dependent tables: group_members, messages, pending_invites, pending_welcomes, message_fetch_watermarks.

4. Broadcast: The server broadcasts a GroupDeletedEvent to all former members, including the admin who performed the deletion.

Client Behavior

When a client receives a GroupDeletedEvent:

1. Delete local MLS group state for the group (delete_mls_group_state).
2. Remove the group from the local room list.
3. Remove the group from the group ID mapping.
4. If the deleted group was the active room, deactivate it.
5. Display a system message indicating the group was deleted.