Comments on: Defensive AJAX and AJAX retries in jQuery

By: booshtukka

booshtukka — Tue, 23 Nov 2010 14:54:32 +0000

Thanks, I’ll take a look.

By: Mark van Wyk

Mark van Wyk — Wed, 10 Nov 2010 18:32:44 +0000

This does not (as yet) work in JQuery 1.4.3

By: Mark van Wyk

Mark van Wyk — Wed, 10 Nov 2010 18:25:27 +0000

This looks like a fantastic idea but for some odd reason, I’m getting a too much recursion error. Any ideas?

$.ajax ({
url: url,
data: data,
timeout: 2000,
requestId: model.requestId,
tryCount: 0,
retryLimit: 4,
success: function(data) {
controller.log(“Request ” + this.requestId + ” success.”);
fn_success(data);
return;
},
error: function(xhr, status, ex) {
if (status == ‘error’ && xhr.status == 404) {
controller.log (“Request ” + this.requestId + ” failed for good.”);
fn_error();
return;
}
this.tryCount++;
if (this.tryCount <= this.retryLimit) {
controller.log ("Request " + this.requestId + " failed. Trying " + this.tryCount + " time.");
controller.log(this);
$.ajax(this);
return;
} else {
controller.log ("Request " + this.tryCount)
fn_error();
return;
}
}
});

By: philk

philk — Tue, 21 Sep 2010 23:03:11 +0000

there seems to be a problem when using timeout in this code:
ajaxEx: function(settings, urls) {
var originalErrorFunc = settings.error;
var succeeded = false;
var result;
var urls = (settings.url instanceof Array) ? settings.url : [settings.url];
//settings.mode = ‘sync’;
settings.error = function(xhr, status, error) {
var url = urls.shift();
//alert(“Failed: ” + settings.url + “\nStatus: ” + status + “\n” + error + “\nNext: ” + url);
if (url) {
settings.url = url;
$.ajax(settings);
} else if (originalErrorFunc) {
originalErrorFunc.apply(settings, arguments);
}
};
settings.url = urls.shift();
$.ajax(settings);
}

you would call the function like $.ajaxEx({url: []}); and a new url will be used for the next ajax call if the previous fails with an error. However, the first error is most likely “parsererror” when loading xml data. The second error reported will be timeout.

By: Jintu

Jintu — Wed, 01 Sep 2010 06:52:48 +0000

Really worth to read this tutorial

By: booshtukka

booshtukka — Mon, 19 Jul 2010 10:30:26 +0000

See the jQuery AJAX documentation… It is for more information if it is available. I could safely have missed out this parameter, but it is useful in case we wanted to do something more "real world".

By: Ben

Ben — Fri, 09 Jul 2010 00:25:59 +0000

Excellent!!!! What is the errorThrown parameter used for though? It’s not called anywhere?

By: Aidan

Aidan — Wed, 03 Feb 2010 12:41:44 +0000

Great tutorial. Too bad this blog isn’t as active anymore. Can you get in touch with me as I could not locate your contact details. Thanks.

By: Gavin Williams

Gavin Williams — Tue, 18 Aug 2009 09:50:12 +0000

Agree quite a bit, this is the reason why I hate to love implementing AJAX, “fragile” has to be the most accurate term for it, especially if the backend isn’t as strong as the front end implementation, as it’s quite often flakey!

Really nice post.