create websocket cache server

src/WebSocketLifeCycle.ts

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+
+export class WebSocketLifecycle {
+  cachedValue: string = "";
+  reconnectTimer?: Timer;
+
+  socket?: WebSocket;
+  readonly socketUrl: string;
+  readonly name: string;
+
+  private messages: string[];
+  
+  constructor(socketUrl: string, name: string) {
+    this.name = name;
+    this.socketUrl = socketUrl;
+    this.messages = [""];
+  }
+
+  public registerWebSocketHandler() {
+    this.socket = new WebSocket(this.socketUrl);
+
+    // message is received
+    this.socket.addEventListener("message", event => {
+      console.log(`WS: ${this.socketUrl} got message`, event)
+      this.messages = [event.data];
+    });
+
+    // socket opened
+    this.socket.addEventListener("open", event => {
+      console.log(`WS: ${this.socketUrl} opened`);
+
+      if (this.reconnectTimer) {
+        console.log(`WS: ${this.socketUrl} cancelling reconnect timer`)
+        clearInterval(this.reconnectTimer);
+        this.reconnectTimer = undefined;
+      }
+    });
+
+    // socket closed
+    this.socket.addEventListener("close", event => {
+      console.log(`WS: ${this.socketUrl} closed`);
+      if (!this.reconnectTimer) {
+        console.log(`WS: ${this.socketUrl} scheduling reconnect every 5s`);
+        this.reconnectTimer = setInterval(() => {
+          console.log(`WS: ${this.socketUrl} trying to reconnect`);
+          this.registerWebSocketHandler();
+        }, 5000);
+      }
+    });
+
+    // error handler
+    this.socket.addEventListener("error", event => {
+      console.error(`WS: ${this.socketUrl} error: `, event);
+    });
+  }
+
+  public getLatestMessage(): any {
+    return JSON.parse(this.messages[0]);
+  }
+}

src/WebhookServer.ts

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+import { Hono } from "hono";
+import { prettyJSON } from "hono/pretty-json";
+import { serve } from "bun";
+import type { WebSocketLifecycle } from "./WebSocketLifeCycle";
+
+export class WebhookServer {
+  readonly app: Hono;
+  readonly websockets: WebSocketLifecycle[];
+
+  constructor(websockets: WebSocketLifecycle[]) {
+    this.websockets = websockets;
+    this.app = new Hono();
+
+    this.app.use(prettyJSON());
+
+    this.app.get(`/api/:wsName`, async (c) => {
+      const wsName = c.req.param('wsName');
+
+      const webSocket = this.websockets.find(ws => ws.name === wsName);
+
+      if (!webSocket) {
+        return c.json({
+          err: "unknown websocket",
+        }, 404);
+      }
+
+      return c.json(webSocket.getLatestMessage(), 200);
+    });
+  }
+
+  listen(port: number) {
+    return serve({
+      fetch: this.app.fetch,
+      port,
+    });
+  }
+}

src/server.ts

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+import { WebhookServer } from "./WebhookServer";
+import { WebSocketLifecycle } from "./WebSocketLifeCycle";
+
+const socket = new WebSocketLifecycle("wss://ntfy.chromart.cc/buzzer/ws", "buzzer");
+socket.registerWebSocketHandler();
+
+const wsServer = new WebhookServer([socket]);
+wsServer.listen(8080);