LiChess

Summarizing my attempts to understand LiChess.

Arch

https://pbs.twimg.com/media/CYGyi12UwAArCU9?format=png&name=medium

• The main diagram is not very clear, or helpful.

• Where's Redis? Or does the diagram predate it?

API

https://lichess.org/api

• They stream board events with ndjson https://lichess.org/api#operation/apiStreamEvent. It's long polling I suppose?

• Can't find API to actually make moves. I suppose it's done via websockets?

• Can't find API to actually do puzzles. Only see API to get daily puzzle. Perhaps it's also done with web sockets.

• There's an API to send a message, but I see no API to view messages.

Code

Source Code • lichess.orglichess

Lila

https://github.com/ornicar/lila

• Doesn't seem to have many tests.

• Board literals in tests whoa https://github.com/ornicar/scalachess/blob/master/src/test/scala/BishopTest.scala#L32-L40

WS

• WS deploy command whoa https://github.com/ornicar/lila-ws/blob/master/deploy.sh Just like that.
• Very magic numbers are all over the place https://github.com/ornicar/lila-ws/blob/3bf35711609034235dcf77e2fccfc5b1c4a53a5b/src/main/scala/LilaWsServer.scala#L65-L74
• Few comments, very hard to follow which class is doing what.

• No tests apparently.

• WFH is anaMove?

• Actually receive move from Lila https://github.com/ornicar/lila-ws/blob/c18ac9df67893e22c2196f5745c53eae83b8251b/src/main/scala/LilaHandler.scala#L128-L132
• Send the move to watching clients https://github.com/ornicar/lila-ws/blob/c18ac9df67893e22c2196f5745c53eae83b8251b/src/main/scala/Fens.scala#L56-L77

UI

• Arguments: t, d, o. https://github.com/ornicar/lila/blob/6bdf93d27ac08cb9321e439fcf3b10f235c373ac/ui/site/src/component/socket.ts#L147 How is anyone supposed to understand what it means?

Tracking how a move is sent to the server:

• https://github.com/ornicar/lila/blob/97a46cfa5d7334904d0ee0698e7822ee9314d052/ui/round/src/ctrl.ts#L303
• https://github.com/ornicar/lila/blob/97a46cfa5d7334904d0ee0698e7822ee9314d052/ui/round/src/ctrl.ts#L277

Puzzler

GitHub - ornicar/lichess-puzzlerGitHub

Overall, seems very basic stuff. It feels like it's possible to do a lot better.

• Main script (?) https://github.com/ornicar/lichess-puzzler/blob/master/bin/import-more.sh
• Generator https://github.com/ornicar/lichess-puzzler/tree/master/generator
• Extracting puzzle from a game https://github.com/ornicar/lichess-puzzler/blob/master/generator/generator.py

Cheat detection

https://github.com/clarkerubber/irwin

https://github.com/ornicar/lila/tree/master/modules/irwin/src/main