Socket.io发送到特定客户端

Question

could anybody tell me why I'm getting an undefined response?

It's definitely saving the socket.io socket ID, as I've checked. The typeof the response is "undefined". It's successfully connecting, as I can see it on the server code (main.js), and I can see the uuid as well as the socket id.

main.js

'use strict';
var uuid = require('node-uuid');
var fs = require('fs');
var fse = require('fs-extra');
var rimraf = require('rimraf');
var socketio = require('socket.io')();

var cnf = require('./config.js');

var myId = uuid.v4();
var connectedWorkers = {};

if (!fs.existsSync('runtime')) {
    console.log("runtime directory cannot be found");
}

rimraf.sync('runtime/generated');
fs.mkdirSync("runtime/generated", function(err){
    if(err){ 
        console.log(err);
        response.send("ERROR! Can't make the directory! \n");    // echo the result back
    }
});

socketio.on('connection', function(socket){
    console.log('connection!');
    var newId = uuid.v4();
    connectedWorkers[newId] = socket.id;
    socketio.sockets.in(connectedWorkers[newId]).emit("test", {asd:"asdasd"});
    console.dir(connectedWorkers);
});
socketio.listen(3000);

client.js

'use strict';

var cnf = require('./config.js');

var socket = require('socket.io-client')(cnf.serverURL);

socket.on('connect', function(data){
    console.log(data);
    socket.on('event', function(data){
    });
    socket.on('disconnect', function(){});
});

Answer 1

It's simply because you're logging wrong.

socket.on('connect', function(data){    // this 'connect' event have no parameter. Just function()
    console.log(data);                  // therefore 'data' here will be 'undefined'
});

socket.on('test', function(data){
    console.log(data);                  // this will return {asd:"asdasd"} as you emitted this.
});

Answer 2

You can call emit directly on your sockets :

socketio.on('connection', function(socket){
    socket.emit("test", {asd:"asdasd"});
});

Answer 3

You can try to listen test event on the client side:

'use strict';

var cnf = require('./config.js');

var socket = require('socket.io-client')(cnf.serverURL);

socket.on('test', function(data){
    console.log(data.asd);  //should print "asdasd"
});