Ajax requests are, generally speaking, used to update the document or meant to send and fetch new data to and from the server. In Ajax heavy apps, you might end up sending the same request on numerous occasions and not always expect the server to respond with the same results.

This can cause problems with caching. Internet Explorer in particular will see an ajax request with the same parameters and just return the results it got last time, which, well, sucks.

I have this trick that I’ve been using for a while now and I figured I’d release it. The solution is to include a value in your request that’s always different. My solution has been to add a “noCache” value set to the current time. So long as I’m not sending the same request more than once in a millisecond, this solves my problems.

Hot on the heals of yesterday’s plugin (Class.refactor), I’m releasing this tweak on the Request classes that introduces the ‘noCache’ option that will automate this for you. Simply set the ‘noCache’ option to true and you’re all set.

new Request({
    url: '/foo.php',
    data: {...some data...},
    noCache: true
}).send()

Don’t want to set it every time? No problem, just switch the default for the option to true with Class.refactor:

(function(){ //let's not pollute the global namespace
    var setNoCache = function(cls) {
        return Class.refactor(cls, options: {
            noCache: true
        });
    };
    Request = setNoCache(Request);
    Request.HTML = setNoCache(Request.HTML);
})();
//all future instances of Request and Request.HTML
//default to using the noCache functionalty

Man. I’m on a roll this week. You can download this script on the download page and view the docs.

This entry was posted on Thursday, November 20th, 2008 at 2:49 pm and is filed under Ajax, Code Releases. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.