socket.io不接收/发送

Question

I have a simple setup where I have some draggable divs and I want to use sockets.io to update the position between clients.

On my client (index.html) I have :

    // find the elements
    var elements = document.getElementsByClassName('ball'),
        labelsX = document.getElementsByClassName('coords-x'),
        labelsY = document.getElementsByClassName('coords-y');

    // loop over the 3 items...
    for (var n = elements.length; n--;) {

        // ... augment our default options with individual `onDrag` handlers
        var opts = {
            onDrag: onDragFactory(n),
            setCursor: true
        };

        // ... and initialize drag for each
        window.d = new Draggable(elements[n], opts);
        console.log('ddd');
    }

    // bind `n` to its value at iteration time
    function onDragFactory (n) {

        return function (element, x, y) {

            //This doesnt seem to work
            console.log(elements[n].style.top);     
            socket.emit('positionx', elements[n].style.top);        


            socket.on('positionx', function(positionx){
              elements[n].style.top= positionx.value();
            });


        }

    }

My server is then :

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

    var publicPath = path.resolve(__dirname, 'public');

    app.use(express.static(publicPath));

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



    //Server Side Listen for an event from the client
    io.on('connection', function(socket){

       socket.on('positionx', function(positionx){
           console.log('recieving');
           console.log(positionx);             

        io.emit('positionx', positionx);
      });  

    });

    http.listen(3000, function(){
      console.log('listening on *:3000');
    });

The server however doesn't seem to receive any information. Is there something I'm doing wrong? Any help would be much appreciated!

Answer 1

In your client you need to define socket.

var socket = io();

Also, make sure you are including socket.io-xxxjs prior to calling socket.io in your javaScript. You are probably already doing this, but it's unclear without seeing more code.