how to use socket.io in controller file

Question

I am using Node.JS Express and socket.io. So my idea was to emit the message directly from my controller’s insert-method. In my server.js file, iam creating the socket.io object and try to make it accessible for other modules:

My server.js is like this

require('rootpath')();
var express = require('express');
var app = express();
var cors = require('cors');
var bodyParser = require('body-parser');
var expressJwt = require('express-jwt');
var config = require('config.json');

var mongoose = require('mongoose');  

mongoose.connect(config.connectionString);
var db = mongoose.connection;

db.on('error',console.error.bind(console,'Connection error'));
db.on('open',function(){
    console.log('connected');
});


app.use(cors());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

// use JWT auth to secure the api, the token can be passed in the authorization header or querystring
app.use(expressJwt({
    secret: config.secret,
    getToken: function (req) {
        if (req.headers.authorization && req.headers.authorization.split(' ')[0] === 'Bearer') {
            return req.headers.authorization.split(' ')[1];
        } else if (req.query && req.query.token) {
            return req.query.token;
        }
        return null;
    }
}).unless({ 
    path: [
        '/users/authenticate',
        '/users/register',
        '/users',
        '/chats','/chats/sendMessage',
        '/rooms','/rooms/create',
        '/chats/connection',
        '/chats/add-message'

    ] 
}));

// routes
app.use('/users', require('./controllers/users.controller'));
app.use('/chats', require('./controllers/chats.controller'));
app.use('/rooms', require('./controllers/rooms.controller'));


var http = require('http').Server(app);
var io = require('socket.io')(http);


io.on('connection', (socket) => {
    console.log('The user is connected');

    socket.on('new-message', (message,userInfo) => {
        console.log(userInfo);
        console.log(message);

      io.emit('message', {type:'new-message', text: message});   
    });

    socket.on('disconnect', function(){
      console.log('The user is disconnected');
    });

    socket.on('add-message', (message,userInfo) => {
        console.log(userInfo);
        console.log(message);
      io.emit('message', {type:'new-message', text: message});   
    });

    socket.on('add-record', (record) => {
      io.emit('getrecord', {type:'new-record', text: record});   
    });

  });


// start server
var port = process.env.NODE_ENV === 'production' ? 80 : 4000;
var server = http.listen(port, function () {
    console.log('Server listening on port ' + port);
});

Client - Data received Emit welcome message on connection

how can i use this below socket connection in chat.controller.js

io.on('connection', (socket) => {
    console.log('The user is connected');

    socket.on('new-message', (message,userInfo) => {
        console.log(userInfo);
        console.log(message);

      io.emit('message', {type:'new-message', text: message});   
    });

    socket.on('disconnect', function(){
      console.log('The user is disconnected');
    });

    socket.on('add-message', (message,userInfo) => {
        console.log(userInfo);
        console.log(message);
      io.emit('message', {type:'new-message', text: message});   
    });

    socket.on('add-record', (record) => {
      io.emit('getrecord', {type:'new-record', text: record});   
    });

  });

and i am creating controller file like this chats.controller.js

var config = require('config.json');
var express = require('express');
var router = express.Router();
var userService = require('../services/user.service');
var chatService = require('../services/chat.service');

// routes
router.post('/sendMessage', send);
router.get('/', getAll);

module.exports = router;

function send(req, res) {

    chatService.sendMessage(req.body)
        .then(function () {
            res.sendStatus(200);
        })
        .catch(function (err) {
            res.status(400).send(err);
        });



}

function getAll(req, res) {
    chatService.getAllMessage()
        .then(function (chats) {
            res.send(chats);
        })
        .catch(function (err) {
            res.status(400).send(err);
        });
}

function getCurrent(req, res) {
    userService.getById(req.user.sub)
        .then(function (user) {
            if (user) {
                res.send(user);
            } else {
                res.sendStatus(404);
            }
        })
        .catch(function (err) {
            res.status(400).send(err);
        });
}

function update(req, res) {
    userService.update(req.params._id, req.body)
        .then(function () {
            res.sendStatus(200);
        })
        .catch(function (err) {
            res.status(400).send(err);
        });
}

function _delete(req, res) {
    userService.delete(req.params._id)
        .then(function () {
            res.sendStatus(200);
        })
        .catch(function (err) {
            res.status(400).send(err);
        });
}

And also i have created one service file name is chat.service.js

var config = require('config.json');
var _ = require('lodash');
var jwt = require('jsonwebtoken');
var bcrypt = require('bcryptjs');
var Q = require('q');
var mongoose = require('mongoose');  

var Chat = require('../model/chat');

var service = {};

service.sendMessage = sendMessage;
service.getAllMessage = getAllMessage;

module.exports = service;

function sendMessage(userParam) {
    var deferred = Q.defer();

    var chat = new Chat({
        room_id:userParam.from_id,
        from_id:userParam.from_id,
        to_id:userParam.to_id,
        chatrp_id:userParam.chatrp_id,
        message:userParam.message
    });

    chat.save(function (err,doc) {  
        if (err) deferred.reject(err.name + ': ' + err.message);
            deferred.resolve();
    }) 

    return deferred.promise;
}

function getAllMessage() {
    var deferred = Q.defer();

    Chat.find({},function (err, response) {
        if (err) deferred.reject(err.name + ': ' + err.message);

        // return users (without hashed passwords)
        response = _.map(response, function (res) {
            return _.omit(res, 'hash');
        });

        deferred.resolve(response);
    });

    return deferred.promise;
}

But is is neither giving me an error or not working.

Can anyone please help, how can I export that in a separate file so that client and server code can be separated?

Thanks in advance for helping.

Answer 1

This how I got this to work.

Steps are as follows:

1) I created a utils folder, inside which I created a file named socket.js

utils/socket.js

const Server = require('socket.io');
const io = new Server();

var Socket = {
    emit: function (event, data) {
        console.log(event, data);
        io.sockets.emit(event, data);
    }
};

io.on("connection", function (socket) {
    console.log("A user connected");
});

exports.Socket = Socket;
exports.io = io;

2) Then in my server(app.js) I did this

app.js

const app = express();

const server = http.createServer(app);
const { io } = require("./utils/socket");
io.attach(server);


module.exports = app;

3)After this 2 steps, In your controller file or any other file(s) where you need to emit an event, you can then just do this:

const { Socket } = require("../../utils/socket");

Socket.emit("newMessage", {
      message: "hello from controller"
 });

Answer 2

To emit messages from your controllers, the controllers need to have access to the original socket.io instance.

So, in chats.controller.js I would do like this:

module.exports = function(io){
    return {
        function: getAll(req, res){
           // here you now have access to socket.io.
           // you can either do:
           io.emit('new-message',{
               // new message object
           });

           // or you can include your chat service the same way
           // that this file is included and call the appropriate function
        },
    }
};

To use this controller, just do

const someController = require('./path/to/chats.controller.js')(io);

You can do exactly the same in your service file.