Spaces:
Running
Running
| Pokemon Showdown architecture | |
| ============================= | |
| At the highest level, PS is split into three parts: | |
| - Game server (**[smogon/pokemon-showdown](https://github.com/smogon/pokemon-showdown)**) | |
| - Client (**[smogon/pokemon-showdown-client](https://github.com/smogon/pokemon-showdown-client)**) | |
| - Login server (**[smogon/pokemon-showdown-loginserver](https://github.com/smogon/pokemon-showdown-loginserver)**) | |
| All three communicate directly with each other. | |
| A user starts by visiting `https://play.pokemonshowdown.com/`. This is handled by an Apache server (in the Client), which serves mostly static files but uses some PHP (legacy, intended to be migrated to Loginserver). | |
| The user's web browser (running Client code) will then communicate with the Login server (mounted at `https://play.pokemonshowdown.com/api/` to handle logins mostly, or otherwise interface with the Client databases one way or another). | |
| The user's web browser will also connect to the Game server, through SockJS. The Game server handles the chat rooms, matchmaking, and actual battle simulation. | |
| The Game server also communicates with the Login server, to handle replay uploads (and, for the main server, ladder updates). | |
| Game server | |
| ----------- | |
| The game server is written in TypeScript and runs on Node.js. | |
| Its entry point is [server/index.ts](./server/index.ts), which launches several major components: | |
| - [server/sockets.ts](./server/sockets.ts) sets up a SockJS (abstracted WebSocket) server to accept connections from clients | |
| - [server/users.ts](./server/users.ts) sets up `Users`, which wraps the SockJS connections in a system that handles users | |
| - [server/rooms.ts](./server/rooms.ts) sets up `Rooms`, which handles the individual chat rooms and battle rooms | |
| - [server/chat.ts](./server/chat.ts) sets up `Chat`, which handles chat commands and messages coming in from users (all client-to-server commands are routed through there) | |
| `Rooms` also includes support for battle rooms, which is where the server connects to the game simulator itself. Game simulation code is in [sim/](./sim/). | |
| Client | |
| ------ | |
| The client is built in a mix of TypeScript and JavaScript, with a mostly hand-rolled framework built on Backbone. There’s a rewrite to migrate it to Preact but it’s very stalled. | |
| Its entry point is [index.template.html](https://github.com/smogon/pokemon-showdown-client/blob/master/play.pokemonshowdown.com/index.template.html) | |
| It was written long ago, so instead of a single JS entry point, it includes a lot of JS files. Everything important is launched from [js/client.js](https://github.com/smogon/pokemon-showdown-client/blob/master/play.pokemonshowdown.com/js/client.js) | |
| Login server | |
| ------------ | |
| The client’s login server, which handles logins and most database interaction, is written in TypeScript. The backend is currently split between a MySQL InnoDB database (for users, ladder, and most other things) and a Postgres (technically Cockroach) database (for Replays). | |
| Its entry point is [server.ts](https://github.com/smogon/pokemon-showdown-loginserver/blob/master/src/server.ts). | |
| It's intended to replace all of the old PHP code in the Client, but that migration is only halfway done at the moment. | |