Implements direct-message (DM) chat send and history endpoints:
- Migration 0011_add_dm_last_read.py (last_read_at on conversation_participants)
- Models updated in backend/app/models/chat.py
- Router in backend/app/routers/chat_dm.py:
- POST /api/chat/dm/{user_id}/messages (send DM, filtered via TextFilter, rate-limited via Redis)
- GET /api/chat/dm/{user_id}/messages (paginated history, updates last_read_at)
- GET /api/chat/dm/conversations (conversations list, last message, unread count)
- Blocks enforced in both directions (cannot send to/from blocked users)
- Self-messaging prevented, peer exist check, auth required
- Integration tests in backend/tests/test_chat_dm.py
Independently re-verified: 14/14 new DM chat tests pass,
272/272 full backend regression suite passes with zero regressions.
docs/planning/social.md US-4, task 6: conversations,
conversation_participants, messages (DM + world/room chat), and
message_reports, following app/models/social.py's conventions (native
enums, explicit index/constraint names, CASCADE FKs where appropriate).
Delete behavior, chosen per-relationship:
- conversations.user_a_id/user_b_id -> CASCADE: a DM is meaningless with
one of its two participants gone, so it cascades away entirely
(participants + messages with it).
- messages.sender_id -> SET NULL: world/room chat history and reported
messages must survive the sender's account being deleted, matching the
existing actor-reference convention (WorldChunk.updated_by_id,
WorldChunkRevision.actor_id).
- messages.world_id/room_id -> CASCADE: chat scoped to a world/room has no
meaning once that world/room is gone (mirrors WorldChunk).
- message_reports.message_id -> SET NULL (not CASCADE): a moderation
report must outlive the message it's about, mirroring
WorldChunkRevision's audit-trail-survives-deletion precedent.
- message_reports.reporter_id/moderator_id -> SET NULL: audit-actor
references, same reasoning.
Models + migration only, no endpoints, no text filtering (sibling tasks).
Verified: migration upgrade/downgrade/upgrade round-trip against a real
Postgres with schema inspected via \d against spec; new model tests cover
DM creation, pair uniqueness + ordering check constraint, world/room
messages, report defaults, and cascade behavior for both
conversation-deletion and sender-deletion; full backend suite (160 tests)
passes with no regressions.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y2FESCaMXeJpC9gSctiEeD
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