Hello,

I am writing an web app which needs to subscribe to multiple channels via javascript. I am using Atmosphere and Jersey as backend. However the jQuery plugin they work with only supports 1 channel. I've start buidling my own implementation. Now it works oke, but when i try to subscribe to 2 channels only 1 channel gets notified.

Is the XMLHttpRequest blocking the rest of the XMLHttpRequests?

Here's my code:

function AtmosphereComet(url)
{
    this.Connected = new signals.Signal();
    this.Disconnected = new signals.Signal();
    this.NewMessage = new signals.Signal();

    var xhr = null;
    var self = this;
    var gotWelcomeMessage = false;
    var readPosition;
    var url = url;

    var onIncomingXhr = function()
    {
        if (xhr.readyState == 3)
        {
            if (xhr.status==200)  // Received a message
            {
                var message = xhr.responseText;

                console.log(message);

                if(!gotWelcomeMessage && message.indexOf("") > -1)
                {
                    gotWelcomeMessage = true;

                    self.Connected.dispatch(sprintf("Connected to %s", url));
                }
                else
                {
                    self.NewMessage.dispatch(message.substr(readPosition));
                }

                readPosition = this.responseText.length;
            }
        }
        else if (this.readyState == 4)
        {
            self.disconnect();
        }
    }

    var getXhr = function()
    {
        if ( window.location.protocol !== "file:" ) {
            try {
                return new window.XMLHttpRequest();
            } catch(xhrError) {}
        }

        try {
            return new window.ActiveXObject("Microsoft.XMLHTTP");
        } catch(activeError) {}
    }

    this.connect = function()
    {
        xhr = getXhr();
        xhr.onreadystatechange = onIncomingXhr;
        xhr.open("GET", url, true);
        xhr.send(null);
    }

    this.disconnect = function()
    {
        xhr.onreadystatechange = null;
        xhr.abort();
    }

    this.send = function(message)
    {

    }
}

And the test code:

var connection1 = AtmosphereConnection("http://192.168.1.145:9999/botenveiling/b/product/status/2", AtmosphereComet);
var connection2 = AtmosphereConnection("http://192.168.1.145:9999/botenveiling/b/product/status/1", AtmosphereComet);

var output = function(msg)
{
    alert(output);
};

connection1.NewMessage.add(output);
connection2.NewMessage.add(output);

connection1.connect();

In AtmosphereConnection I instantiate the given AtmosphereComet with "new". I iterate over the object to check if it has to methods: "send", "connect", "disconnect". The reason for this is that i can switch the implementation later on when i complete the websocket implementation :) However I think the problem rests with the XmlHttpRequest object, or am i mistaken?

P.S.: signals.Signal is a js observer/notifier library: http://millermedeiros.github.com/js-signals/

Testing:

Firefox 3.6.1.3