Route awareness messages between peers

src/awareness.test.ts

@@ -0,0 +1,55 @@
+import { describe, test, expect, beforeAll, afterAll } from "bun:test";
+import type { Server } from "bun";
+
+describe("awareness routing", () => {
+  let server: Server;
+  const PORT = 4042;
+
+  beforeAll(async () => {
+    // Import and start server on test port
+    process.env.PORT = String(PORT);
+    const mod = await import("./index");
+    server = mod.server;
+  });
+
+  afterAll(() => {
+    server?.stop();
+  });
+
+  test("awareness message routes to other peers in same room", async () => {
+    const ws1 = new WebSocket(`ws://localhost:${PORT}/ws`);
+    const ws2 = new WebSocket(`ws://localhost:${PORT}/ws`);
+
+    const received: unknown[] = [];
+
+    await Promise.all([
+      new Promise(r => ws1.onopen = r),
+      new Promise(r => ws2.onopen = r),
+    ]);
+
+    ws2.onmessage = (e) => {
+      received.push(JSON.parse(e.data));
+    };
+
+    // Both join same room
+    ws1.send(JSON.stringify({ type: "join", room: "test" }));
+    ws2.send(JSON.stringify({ type: "join", room: "test" }));
+
+    await Bun.sleep(50);
+
+    // ws1 sends awareness
+    ws1.send(JSON.stringify({
+      type: "awareness",
+      data: { clientId: 1, cursor: { line: 10, col: 5 } }
+    }));
+
+    await Bun.sleep(50);
+
+    const awareness = received.find(m => m.type === "awareness");
+    expect(awareness).toBeDefined();
+    expect(awareness.data.cursor).toEqual({ line: 10, col: 5 });
+
+    ws1.close();
+    ws2.close();
+  });
+});

src/index.ts

@@ -14,7 +14,7 @@ function isValidRoomName(name: unknown): name is string {
   return /^[a-zA-Z0-9_-]+$/.test(name);
 }
 
-Bun.serve<WsData>({
+export const server = Bun.serve<WsData>({
   port: PORT,
   fetch(req, server) {
     const url = new URL(req.url);
@@ -77,6 +77,15 @@ Bun.serve<WsData>({
           }
           break;
         }
+        case "awareness": {
+          if (ws.data.room) {
+            const session = getSession(ws.data.room);
+            if (session && "data" in msg) {
+              session.broadcastAwareness(client, msg.data);
+            }
+          }
+          break;
+        }
       }
     },
     close(ws) {

src/protocol.ts

@@ -46,9 +46,7 @@ function isClientMessage(obj: unknown): obj is ClientMessage {
         Array.isArray(msg.data) && msg.data.every((n) => typeof n === "number")
       );
     case "awareness":
-      return (
+      return typeof msg.data === "object" && msg.data !== null;
-        Array.isArray(msg.data) && msg.data.every((n) => typeof n === "number")
-      );
     default:
       return false;
   }