Socket.io: Nodejs Socket.io Express failed to handshake after calling HTTP API

[almgwary]

You want to:

• [x] report a bug

Current behaviour

I am using SocketIo with Nodejs, Express server and MongoDB, I followed the documentation . it works fine when connecting multiple clients they can send messages to each other without any problem . when I made an Http request, I cannot connect any new clients and get this error.

socket.io.js:7370 WebSocket connection to
'ws://localhost:28232/socket.io/?userId=userAmr&EIO=3&transport=websocket&sid=wNTTgrUD-PSeNaIcAAAF'
failed: Error during WebSocket handshake: Unexpected response code:
400

the other connected users before the Http request can continue sending messages without any problem.

I debugged the Socket library and found the client socket request go to connect function then fire errorCode:1

This this my code

/**
 * Create Express server.
 */
const app = express();


// API endpoint
app.get('/api/test',(req,res)=>{
    res.status(200).send({test:"test"});
});



/**
 * Init socket
 */
const server = require('http').Server(app);
const io = require('socket.io')(server);


io.on('connection', (socket) => {

        // emit message to group
        socket.on('emitMessage', (data, callback) => {
                io.emit('emitMessage', data);
        });
});

This my question on stack overflow https://stackoverflow.com/q/47375814/6786941

[almgwary]

i found the problem, the package express-status-monitor was making this wrong behavior .

try to remove it, and it will work perfectly

 // comment these lines, as they making the issue
 // const expressStatusMonitor = require('express-status-monitor'); 
 // app.use(expressStatusMonitor());

The final code:

let app = require('express')();

// these two lines were making the problem, please comment them. if you want to reproduce the problem enable them again 
// const expressStatusMonitor = require('express-status-monitor');
// app.use(expressStatusMonitor());

let http = require('http').Server(app);
let io = require('socket.io')(http);
let port = process.env.PORT || 3000;

app.get('/', function(req, res){
    res.sendFile(__dirname + '/index.html');
});



app.get('/api/v0/availabilities',(req,res)=>{
    res.status(200).send({test:"test"});
});


io.on('connection', (socket) => {

    // emit message to group
    socket.on('emitMessage', (data) => {
        io.emit('emitMessage', data);
    });
});

http.listen(port, function(){
    console.log('listening on *:' + port);
});

This my question on stack overflow https://stackoverflow.com/q/47375814/6786941

This my answer on stack overflow https://stackoverflow.com/a/47411701/6786941

[kamalptw]

@almgwary You, Sir, Are too good. I was facing the exact same issue. I removed expressStatusMonitor and it worked like a charm! Thank you! After a lot of days of searching, I was able to finally solve this after using your suggestion. Thanks a ton!