bfcache: server - Implement WebSocket server functionality

* Added WebSocketServer class with configurable options
* Introduced WebSocketServerFactory for creating WebSocket relay servers
* Updated index.ts to set up a server with WebSocket support and handle various signals for graceful shutdown

Web/bfcache/server/src/index.ts

@@ -1 +1,36 @@
-console.log('hello claris');
+import {LoggerFactory} from '@techniker-me/logger';
+import WebSocketServerFactory from './net/websockets/WebSocketServerFactory';
+
+LoggerFactory.setLoggingLevel('All');
+
+const webSocketRelayServer = WebSocketServerFactory.createWebSocketRelayServer();
+const PORT = parseInt(process.env.PORT || '4444', 10);
+
+const server = Bun.serve({
+  port: PORT,
+  fetch: (request, server) => {
+    if (server.upgrade(request)) {
+      return;
+    }
+
+    return new Response('hi');
+  },
+  websocket: webSocketRelayServer
+});
+
+process.on('SIGINT', () => {
+  console.log('Received [SIGINT] stopping server');
+  server.stop();
+});
+
+process.on('SIGKILL', () => {
+  console.log('Received [SIGKILL] stopping server');
+  server.stop();
+});
+
+process.on('SIGTERM', () => {
+  console.log('Received [SIGTERM] stopping server');
+  server.stop();
+});
+
+console.log(`Server listening on [:${server.port}]`);

Web/bfcache/server/src/net/websockets/WebSocketServer.ts

@@ -1,5 +1,5 @@
 import type {ServerWebSocket, WebSocketCompressor} from 'bun';
-import type {Seconds, Bytes} from './types/Units'; 
+import type {Seconds, Bytes} from '../../types/Units';
 
 export type PerMessageDeflate =
   | boolean

Web/bfcache/server/src/net/websockets/WebSocketServerFactory.ts

@@ -0,0 +1,37 @@
+import {LoggerFactory} from '@techniker-me/logger';
+import WebSocketServer, {WebSocketServerOptions} from './WebSocketServer';
+import {ServerWebSocket} from 'bun';
+
+export default class WebSocketServerFactory {
+  public static createWebSocketRelayServer(): WebSocketServer {
+    const logger = LoggerFactory.getLogger('WebSocketRelayServer');
+    const clients = new Set<ServerWebSocket>();
+    const webSocketRelayServerOptions: WebSocketServerOptions = {
+      onSocketError: (client, error) => logger.error(`Error: [%o] [${error.message}]`, client),
+      onSocketOpen: client => {
+        logger.debug('New WebSocketClient [%o]', client);
+
+        clients.add(client);
+      },
+      onSocketMessage: (fromClient, message) => {
+        logger.debug(`Relaying message [%o]`, message);
+
+        for (const client of clients) {
+          if (client === fromClient) {
+            continue;
+          }
+
+          client.send(message);
+        }
+      },
+      onSocketClose: client => clients.delete(client),
+      onSocketDrain: client => logger.debug('Client drain [%o]', client),
+      publishToSelf: false
+    };
+
+    return new WebSocketServer(webSocketRelayServerOptions);
+  }
+  private constructor() {
+    throw new Error('WebSocketServerFactory is a static class that may not be instantiated');
+  }
+}