error handling with .post()

Question

I have to modify a project written by someone else. Because the code is a mess I can't really change this $.post() (or replace it by $.ajax()). What I need to do, is to know if the post returns something else then JSON and return it.

$.post('balbal.html', json, function(data) { ... my coude ... }, 'json') 

I can see the post response in the console.log. Is there a simple way to retrieve it?

Answer 1

Define the error callback immediately after the post. Note the semi-colon placement only at the end.

$.post('balbal.html', json, function(data) {     // ... my code ... }) .fail(function(response) {     alert('Error: ' + response.responseText); }); 

http://api.jquery.com/deferred.fail/

For older versions of jQuery (pre-1.8) Use .error instead with the same syntax.

Answer 2

There's a couple of ways to do it, but if you're not getting the error response available through the returned JSON data object, you can use $.ajaxSetup() to define defaults for all ajax calls through jQuery. Even though the $.post() method doesn't specify an error handler or callback in and of itself, the $.ajaxSetup() method will capture any ajax faults and execute the function you define for it.

Alternatively, there is also an $.ajaxError() function that will do the same sort of thing.

Note that this will not work if your JSON response is returned correctly but with a server-side error code. If you want to capture these sorts of cases, you might be best to look for them using the $.ajaxComplete() method