Crate open_chess_server 

The open-chess server, as a library (the open-chess binary is a thin wrapper; integration tests drive the same pieces).

Modules

ai

Playing the computer: POST /api/challenge/ai with level 1–8, as on Lichess. The computer is open-chess’s own engine (chess_analysis::bot) at that level, played by the server itself: a game against ai-level-N, a bot account made on first use, with the level’s fixed rating (Level::rating). A game against it can be rated, as an offline game against the same level in the iOS app is: the player’s rating moves, the computer’s never does, and Glicko gives little for beating a level far below you, so it can’t be farmed.

analyse

The fair-play worker (open-chess analyse): takes finished games off the queue, has Stockfish evaluate every position, and stores a screening report per human player. With no game to screen, it evaluates positions people confirmed from board photos for the position dictionary, scoring every legal move. Run as many as you like (games are claimed with SKIP LOCKED and a lease, so a crashed worker’s game is picked up again).

app

The shared context, and the HTTP server’s routes.

apple

Sign in with Apple, for the iOS app.

auth

Who is calling: this server’s API tokens (bearer) and session cookies.

challenges

Challenges: create (optionally accepted at once with the opponent’s token), accept, decline, cancel, list, and lapse.

cli

The server’s commands, as the open-chess program runs them (the open-chess crate; built with its server feature):

config

Settings, all from the environment (containers on Kubernetes and Cloudflare both pass configuration that way). Every variable has a working default except DATABASE_URL.

db

Postgres: the connection pool, this server’s schema, and the LISTEN connection that fans changes out to every replica.

error

API errors, in Lichess’s shape: {"error": "..."} with a status code.

http

HTTP handlers, grouped as Lichess’s API docs group them.

metrics

Prometheus metrics for the chess server.

model

Rows (accounts, games, challenges) and their Lichess JSON views.

passkeys

Passkeys (WebAuthn): registering them, signing in (or making an account) with one instead of a password, and the passkey check that switches on an admin’s or manager’s rights.

play

Playing a game: moves, resignations, draws, takebacks, aborts, claims, the end of a game (ratings, notifications) and the sweeper that flags clocks and lapses challenges.

push

Apple push notifications for the iOS app: “your move” in correspondence games, a result to confirm. Sent over APNs’ HTTP/2 API with a token signed by the team’s .p8 key (ES256), which is kept for 50 minutes as Apple asks. Off unless CHESS_APNS_KEY, _KEY_ID and _TEAM_ID are set. A device APNs reports gone is forgotten.

vision

Reading a chess board from a photo.

Functions

spawn_background

What every serving replica runs besides HTTP: the LISTEN connection that brings other replicas’ changes in, and the clock/challenge sweeper (rows are claimed with SKIP LOCKED, so replicas don’t collide).

stopped

Resolves once shutdown has begun (the watch guard isn’t held, so the future stays Send).