Getting 404 on some kind of polling - new nodejs project using express-generator

Question

I created a simple project structure using express command from express-generator nodejs module (http://expressjs.com/starter/generator.html).

When I start the app, everything is Ok, except a strange polling call which gets 404 for each request:

Listening on port 3000
GET / 200 533.444 ms - 170
GET /stylesheets/style.css 200 4.643 ms - 111
GET /socket.io/?EIO=3&transport=polling&t=1439686799050-244 404 40.935 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686802114-245 404 27.494 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686806157-246 404 16.291 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686811211-247 404 12.629 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686816239-248 404 20.037 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686821276-249 404 13.513 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686826320-250 404 16.412 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686831383-251 404 10.820 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686836420-252 404 11.827 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686841478-253 404 15.267 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686846669-254 404 12.168 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686851754-255 404 11.569 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686856976-256 404 8.629 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686862211-257 404 6.490 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686867255-258 404 8.431 ms - 1235
GET /socket.io/?EIO=3&transport=polling&t=1439686872285-259 404 14.600 ms - 1235

Any help on how to solve the 404 error? Thanks in advance.

Answer 1

Express-generator don't knows about sockets. You not installed the module 'socket.io', and your server isn't listening sockets.

Solution: http://socket.io/docs/ (official docs)

Sockets can work through many transports: WebSockets, XHR, HTTP and other. Client tries to connect through all available transports, and through HTTP receives response. But response is "404", because request is handled by Express's router, not socket.io, and router don't has suitable routes.