Question

I wrote a very simple AJAX chat app with jQuery. It simply sends your message to a PHP file via AJAX, then writes that message JSON-encoded into a text file for the receiver to pick up. The JSON file is simple, like {“userid”:1,”msg”:”hello there”}, and its stored under the receiver’s user ID. Once the receiver detects a timestamp change on the file, it reads the JSON data out of it.

This works well, and it’s very fast. But now I’m considering scaling etc, and I am unsure how filesystem-based chat like this would work long-term. Should I seriously consider an XMPP server and rewrite the Ajax stuff around it, or keep what I have? Thanks in advance.

Answer 1

If scalability is your concern, then I would definitely consider replacing AJAX with XMPP even if your app has no chat capability in it at all. Although XMPP has a lot of complexity in it at the protocol level, Strophe does a great job at abstracting away that complexity. Here is some sample code that does the XMPP equivalent to an AJAX call.

/**
 * handle the response from the search request
 * @param {Element} retStanza contains the iq result packet
 */
com.dynamicalsoftware.opeye.admin.Category.prototype.handleSearchResult = function(retStanza) {
    var a = goog.dom.getElement(com.dynamicalsoftware.opeye.admin.appAreaId);
    goog.dom.removeChildren(a);
    var categories = iqresult.getElementsByTagName('category');
    for (i=0; i<categories.length; i++) {
    new com.dynamicalsoftware.opeye.admin.Category(com.dynamicalsoftware.opeye.admin.GuiMode.SEARCHRESULT, categories[i]).render(parentDivTabContent);
    }
}

/**
 * perform a search operation
 * @private
 */
com.dynamicalsoftware.opeye.admin.Category.prototype.search = function() {
    var request = $iq({to: 'category@' + com.dynamicalsoftware.opeye.admin.domain, type: 'get'}).c('query', {xmlns: 'http://www.dynamicalsoftware.com/opeye/admin/category'});
    var outstanza = request.tree();
    connection.sendIQ(outstanza, this.handleSearchResult.bind(this));
}