Support Bidirectional communication via Socket.IO

Author: hussein-m-kandil

package-lock.json

@@ -60,6 +60,7 @@
     "passport-jwt": "^4.0.1",
     "passport-local": "^1.0.0",
     "sharp": "^0.34.2",
+    "socket.io": "^4.8.3",
     "winston": "^3.17.0",
     "zod": "^3.24.3"
   },

package.json

@@ -1,6 +1,6 @@
 import * as API from '@/api';
 import * as Middlewares from '@/middlewares';
-import { ALLOWED_ORIGINS } from '@/lib/config';
+import { ALLOWED_ORIGINS, corsOptions } from '@/lib/config';
 import { AppBaseError } from '@/lib/app-error';
 import cookieParser from 'cookie-parser';
 import logger from '@/lib/logger';
@@ -21,13 +21,7 @@ app.use(Middlewares.creationRegistrar);
 app.use(Middlewares.createNonAdminDataPurger());
 
 logger.info('ALLOWED_ORIGINS: ', ALLOWED_ORIGINS);
-app.use(
-  cors({
-    origin: ALLOWED_ORIGINS,
-    credentials: true, // Enable cookies and credentials
-    optionsSuccessStatus: 200, // Align more than 204 with legacy browsers
-  })
-);
+app.use(cors(corsOptions));
 
 app.use('/api/v1', API.V1.apiRouter);
 
@@ -38,4 +32,6 @@ app.use((req) => {
 
 app.use(Middlewares.errorHandler);
 
+export { app };
+
 export default app;

src/app.ts

@@ -1,3 +1,5 @@
+import { CorsOptions } from 'cors';
+
 const ERR = 'EnvVarMissed';
 
 if (!process.env.SECRET) console.error(`${ERR}: SECRET`);
@@ -14,3 +16,9 @@ export const MAX_FILE_SIZE_MB = Number(process.env.MAX_FILE_SIZE_MB) || 2;
 export const TOKEN_EXP_PERIOD = process.env.TOKEN_EXP_PERIOD ?? '3d';
 export const NODE_ENV = process.env.NODE_ENV;
 export const CI = Boolean(process.env.CI);
+
+export const corsOptions: CorsOptions = {
+  origin: ALLOWED_ORIGINS,
+  credentials: true, // Enable cookies and credentials
+  optionsSuccessStatus: 200, // Align more than 204 with legacy browsers
+};

src/lib/config.ts

@@ -0,0 +1,37 @@
+import { corsOptions } from '@/lib/config';
+import { AuthResponse } from '@/types';
+import { Server } from 'socket.io';
+import logger from '@/lib/logger';
+import db from '@/lib/db';
+
+const io = new Server({ cors: corsOptions, serveClient: false });
+
+io.on('connection', (socket) => {
+  const { user } = socket.handshake.auth as Partial<AuthResponse>;
+
+  if (user) {
+    void socket.join(user.id)?.catch();
+    if (user.profile) {
+      socket
+        .join(user.profile.id)
+        ?.catch((error: unknown) => logger.error('Failed to join a socket room', error));
+    }
+    db.profile
+      .update({ where: { userId: user.id }, data: { lastSeen: new Date() } })
+      .then(() => logger.info(`Marked ${user.username} as seen`))
+      .catch((error: unknown) => logger.error(`Failed to mark ${user.username} as seen`, error));
+  }
+
+  const username = user?.username;
+  const { clientsCount } = io.engine;
+
+  logger.info('A socket client is connected', { username, clientsCount });
+
+  socket.on('disconnect', () =>
+    logger.info('A socket client is disconnected.', { username, clientsCount }),
+  );
+});
+
+export { io };
+
+export default io;

src/lib/io.ts

@@ -1,9 +1,16 @@
-import logger from '@/lib/logger';
+import { logger } from '@/lib/logger';
+import { createServer } from 'http';
+import io from '@/lib/io';
 import app from '@/app';
 
-const PORT = Number(process.env.PORT) || 3001;
+export const PORT = Number(process.env.PORT) || 3001;
 
-app.listen(PORT, (error) => {
-  if (error) logger.error(error);
-  logger.info(`The server is running on prot ${PORT}...`);
-});
+const httpServer = createServer(app);
+
+io.attach(httpServer);
+
+httpServer.on('error', (error) => logger.error(error));
+
+httpServer.listen(PORT, () => logger.info(`The server is running on prot ${PORT}...`));
+
+export default httpServer;