Question

187

Use socket.io in expressjs routes instead of in main server.js file

rated 0 times [ 190] [ 3] / answers: 1 / hits: 22575 / 7 Years ago, fri, december 15, 2017, 12:00:00

I have express/nodejs api. I am adding socket.io feature to it. Currently all of my routes are in separate folders and I include them in server.js file and use them as app.use() function.

In server.js file, I also start the express server by listening to a particular port such as 3000 as below.

let server = app.listen(3000);

According to all google searches what I found is that I need to pass server variable to initialize socket.io like following.

let io = require('socket.io')(server);

Now the question is that since it needs this variable then how can I use socket.io in my routes files which are in different folder to emit and receive events from client?

UPDATE

in server.js file

let route = require('./routes/route');



let app = express();



let server = app.listen(3000);



console.log('Listening to port');



let io = require('socket.io')(server);



app.use('/api/1.0/events', route(io));

in route.js file

let express = require('express');



module.exports = (io) => {

    console.log('IO: ', io);

};

UPDATE 2

server.js file

let express = require('express');

let events = require('./routes/events');

let app = express();

let server = app.listen(3000);



let io = require('socket.io')(server);





app.use(function(request, response, next) {

    request.io = io;

    next();

});



app.use('/events', events);

events.js file

let express = require('express');



let Events = require('../models/events');



apiRoutes.post('/new', function(request, response) {

    let newEvent = new Events(request.body);



    newEvent.save((error, result) => {

        if (error) {

            response.json(error);

        } else {

            // console.log('ELSE');

            // request.io.on('connect', socket => {

                // console.log('LISTENING TO SOCKET...');



                request.io.on('EventCreated', data => {

                    console.log('DATA ON Server: ', data);

                });

            // });



            response.json({

                success: true,

                message: 'New event created'

            });

        }

    });

});

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americar

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2 Years ago

answered 7 Years ago terrence · Accepted Answer

There are multiple ways to share the io variable with route files.

When you require() in your route file, pass it the io variable as a constructor argument.

Use app.set(io, io) so you can then use let io = app.get(io) in any file that has access to the app object.

Create a middleware that puts the io object on every req object so you can access it from there any time.

Here's an example of passing it as a constructor argument to the router file:

let server = app.listen(3000);

let io = require('socket.io')(server);



// load other routers

app.use(require(./someRouterFile.js)(io));



// in someRouterFile.js

const express = require('express');



module.exports = function(io) {

    let router = express.Router()



    // define routes

    // io is available in this scope

    router.get(...)



    return router;

}

Here's an example of the app.set() scheme:

let server = app.listen(3000);

let io = require('socket.io')(server);

app.set(io, io);

Then, anywhere in your routes that you have access to the app object, you can get it with:

let io = app.get(io);

Here's an example of using a middleware to set the io object onto every req object so it's available from all routes.

let server = app.listen(3000);

let io = require('socket.io')(server);



// place this middleware before any other route definitions

// makes io available as req.io in all request handlers

app.use(function(req, res, next) {

    req.io = io;

    next();

});



// then in any express route handler, you can use req.io.emit(...)

Here's an example of using an argument to the module constructor without middleware:

// in mysocket.js

module.exports = (io) => {

    console.log('IO: ', io);

    io.on('connect', socket => {

       // handle various socket connections here

    });



    // put any other code that wants to use the io variable

    // in here





};

Then, in your main file:

let server = app.listen(3000);

let io = require('socket.io')(server);



// initialize my socketio module and pass it the io instance

require('./mysocket.js')(io);