websocket-multiplex/multiplex_client.js

WebSocket-multiplex is a thin library on top of SockJS that allows you to do multiplexing of many virtual WebSockets connection over a single physical one.

var WebSocketMultiplex = (function(){


    // ****

    var DumbEventTarget = function() {
        this._listeners = {};
    };
    DumbEventTarget.prototype._ensure = function(type) {
        if(!(type in this._listeners)) this._listeners[type] = [];
    };
    DumbEventTarget.prototype.addEventListener = function(type, listener) {
        this._ensure(type);
        this._listeners[type].push(listener);
    };
    DumbEventTarget.prototype.emit = function(type) {
        this._ensure(type);
        var args = Array.prototype.slice.call(arguments, 1);
        if(this['on' + type]) this['on' + type].apply(this, args);
        for(var i=0; i < this._listeners[type].length; i++) {
            this._listeners[type][i].apply(this, args);
        }
    };


    // ****

    var WebSocketMultiplex = function(ws) {
        var that = this;
        this.ws = ws;
        this.channels = {};
        this.ws.addEventListener('message', function(e) {
            var t = e.data.split(',');
            var type = t.shift(), name = t.shift(),  payload = t.join();
            if(!(name in that.channels)) {
                return;
            }
            var sub = that.channels[name];

            switch(type) {
            case 'uns':
                delete that.channels[name];
                sub.emit('close', {});
                break;
            case 'msg':
                sub.emit('message', {data: payload});
                break;
            }
        });
    };
    WebSocketMultiplex.prototype.channel = function(raw_name) {
        return this.channels[escape(raw_name)] =
            new Channel(this.ws, escape(raw_name), this.channels);
    };


    var Channel = function(ws, name, channels) {
        DumbEventTarget.call(this);
        var that = this;
        this.ws = ws;
        this.name = name;
        this.channels = channels;
        var onopen = function() {
            that.ws.send('sub,' + that.name);
            that.emit('open');
        };
        if(ws.readyState > 0) {
            setTimeout(onopen, 0);
        } else {
            this.ws.addEventListener('open', onopen);
        }
    };
    Channel.prototype = new DumbEventTarget()

    Channel.prototype.send = function(data) {
        this.ws.send('msg,' + this.name + ',' + data);
    };
    Channel.prototype.close = function() {
        var that = this;
        this.ws.send('uns,' + this.name);
        delete this.channels[this.name];
        setTimeout(function(){that.emit('close', {});},0);
    };

    return WebSocketMultiplex;
})();