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ds-chat/backend/README.md
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ksmithandClaude Sonnet 5 c79e96dd48 Phase 2: private rooms, room roles, and invites (backend only)
Adds room_invites table + migration, owner/admin/member role enforcement
(require_room_role), and endpoints for private room creation, room
management (update/delete/leave/transfer-ownership/change-role/remove-member),
and the invite lifecycle (create/list/accept/decline/revoke). Registration
stays invite-only via the CLI from Phase 1 — this is a separate, room-level
invite system for adding existing users to private rooms.

Frontend is untouched: the UI redesign is happening separately, so this phase
is backend + tests only (35 passing). Verified no regressions in the Phase 1
open-room/WebSocket flow via manual smoke test.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-13 20:22:15 -06:00

128 lines
4.9 KiB
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# KeepItTalking backend (Phase 1 + 2)
FastAPI + SQLAlchemy 2.0 (async) + PostgreSQL. Implements auth, room CRUD
(open and private), room roles (owner/admin/member) and invites, and a
single-instance WebSocket chat endpoint. See `../ARCHITECTURE.md` for the
full system design and the phased build plan.
This is an **invite-only site**: there is no public registration endpoint.
Accounts are created by an operator on the app server — see step 4 below.
## Local dev setup
### 1. Postgres
Any local Postgres 14+ works. The quickest option is a container:
```bash
docker run -d --name chatapp-postgres \
-e POSTGRES_USER=chatapp -e POSTGRES_PASSWORD=chatapp -e POSTGRES_DB=chatapp \
-p 5432:5432 postgres:16-alpine
```
Then create the test database (used by the test suite, kept separate from dev data):
```bash
docker exec chatapp-postgres psql -U chatapp -d chatapp -c "CREATE DATABASE chatapp_test;"
```
(Docker here is purely a local-dev convenience for standing up Postgres quickly —
the actual deployment target has no containers at all, see `ARCHITECTURE.md` §9.)
### 2. Python environment
```bash
cd backend
python3 -m venv .venv
.venv/bin/pip install -e ".[dev]"
cp .env.example .env
# edit .env: set SESSION_SECRET to a long random string, e.g.
# python3 -c "import secrets; print(secrets.token_urlsafe(32))"
```
### 3. Migrations
```bash
.venv/bin/alembic upgrade head
```
### 4. Create a user
There's no public sign-up. Create accounts directly with the CLI (add
`--admin` to grant `is_site_admin`, useful ahead of the phase-6 admin portal):
```bash
.venv/bin/python -m app.cli create-user alice alice@example.com "some-password"
```
### 5. Run the dev server
```bash
.venv/bin/uvicorn app.main:app --reload
```
API docs: http://localhost:8000/docs. WebSocket chat endpoint: `ws://localhost:8000/ws/chat`.
### 6. Run tests
Tests run against a real Postgres database (`chatapp_test` by default — native
`ENUM`/`UUID` types aren't faithfully reproduced by SQLite), with each test
wrapped in a transaction that's rolled back afterward:
```bash
DATABASE_URL=postgresql+asyncpg://chatapp:chatapp@localhost:5432/chatapp_test .venv/bin/pytest
```
## Layout
```
app/
main.py create_app(), session middleware, router/WS mounting
config.py environment-driven settings (pydantic-settings)
database.py async engine/session, get_db() dependency
dependencies.py get_current_user, require_room_member, require_room_role
security.py argon2 password hashing
cli.py `python -m app.cli create-user` (account provisioning)
models/ SQLAlchemy models (users, rooms, room_memberships,
messages, room_invites)
schemas/ Pydantic request/response models
routers/ auth, rooms, invites, health
services/ business logic called by routers
ws/ WebSocket connection manager + /ws/chat handler
alembic/ migrations
tests/ pytest + httpx/TestClient tests
```
## Room roles and invites (Phase 2)
Rooms can be `open` (anyone can join via `POST /api/rooms/{id}/join`) or
`private` (`is_private: true` at creation — joinable only via invite). Room
roles are `owner` > `admin` > `member`:
- **member**: post messages, leave the room
- **admin**: edit room settings, create/list/revoke invites, remove plain members
- **owner**: everything admin can, plus delete the room, remove admins, change
member roles, and transfer ownership
Invite flow: an admin+ calls `POST /api/rooms/{id}/invites` with an existing
`target_username`; the invited user sees it via `GET /api/invites/mine` and
calls `POST /api/invites/{id}/accept` (or `/decline`). `GET /api/rooms/mine`
lists every room (open + private) the current user belongs to, alongside
their role.
## Notes / scope decisions
- Invite-only site registration: no `POST /api/auth/register`. Accounts are
provisioned with `python -m app.cli create-user` (see step 4 above). This is
separate from *room* invites above — site accounts vs. room membership.
- Room invites are by **username only**`room_invites.target_email` exists
in the schema (per `ARCHITECTURE.md`) but is unused, since there's no
email-delivery mechanism anywhere in the stack yet.
- Sessions are signed cookies (Starlette `SessionMiddleware`), not a server-side
session table — see `ARCHITECTURE.md`'s rationale (simplest way to carry auth
through a WebSocket handshake). This means there's currently no way to force-
revoke a session server-side; that needs a real session table later.
- No CSRF token yet — `SameSite=Lax` cookies plus a same-origin frontend dev
proxy (see `../frontend/vite.config.ts`) is the accepted phase-1 mitigation.
- Deleting a room explicitly deletes its messages/memberships/invites first
(`room_service.delete_room`) rather than relying on DB-level cascades.