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I'm trying to add a global error handler, and first test was with a call where I purposefully caused error code 401 due to no Access-Control-Allow-Origin header.

I've used Chrome to show the error and verify that it is thrown but I can't figure out how to use the handler to display that message.

The jqxhr.status is 0 and jqxhr.statusText is "error" and the thrownError is an empty string.

Using Chrome, I couldn't find the code and message in any of the function variables. Is there a way to show the code and message seen in Chrome debug mode?

$(document).ajaxError(function (event, jqxhr, settings, thrownError) {
    alert("Global Error Catch. Error of " + thrownError + " at url = " + settings.url + " event type of " + settings.type
        + " with event data of " + event.data + " and event type of " + event.type + " and event target of " + event.target
        + " and the jqXHR.status is " + jqxhr.status + " and jqXHR.statusText is " + jqxhr.statusText
        + " and the jqXHR.responseText  is " + jqxhr.responseText + " and jqXHR.responseXML  is " + jqxhr.responseXML);
});

Looking at the code again I noticed that the button click event uses jQuery.when() to find some input variable values before finally making the ajax call that triggers the 401. Could that be why ajaxError is not showing the error in thrownError?

Update After further testing this is not related to the jQuery.when(). But could this be related to the fact I'm making a cross domain ajax request?

Fiddler can at least see a 401 unauthorized response and when using Chrome debug mode I can see both the 401 unauthorized and the Access-Control-Allow-Origin error message. But is that only sent back to the calling code if I do it myself in the web api? I assumed since it was visible in both Fiddler and Chrome it should be somewhere visible to the global ajaxError handler.

Update2 After more testing this does be related to the nature of a CORS request and not how I've used the global error catching. I might need to create a separate question on that specific topic.

I have also tried the code below and jqXHR.status returns 0 and textStatus = "error" and errorThrown="". I think this is similar to the question posted here on status code 0 for a 401 in fiddler but I don't see a solution posted. I will searching for posts similar to that and if I find one I will include it as an answer. 

$.ajaxSetup({
    error: function (jqXHR, textStatus, errorThrown) {
        if (jqXHR.status == 401) {
            alert("Error 401 : " + textStatus + ": " + errorThrown);
        } else {
            alert("Error: " + textStatus + ": " + errorThrown);
        }
    }
});
Community
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pretzelb
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1 Answers1

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Use thrownError parameter within .ajaxError handler .

Could alternatively use statusCode option of $.ajaxSetup()

$.ajaxSetup({
  statusCode: {
    401: function(jqxhr, textStatus, errorThrown) {
      alert(textStatus + " " + errorThrown)
    }
  }
})
guest271314
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  • I updated the original question to include that `thrownError` is an empty string. I also added a note about how this test case uses `jQuery.when()` in case that is a factor. – pretzelb Mar 02 '16 at 17:49
  • @pretzelb What are response headers from server ? – guest271314 Mar 02 '16 at 18:36
  • According to Fiddler the response headers is "HTTP/1.1 401 Unauthorized" – pretzelb Mar 02 '16 at 22:20
  • @pretzelb What does `jqxhr.getAllResponseHeaders()` log at `console` ? See also http://stackoverflow.com/questions/17330302/why-non-custom-headers-in-access-control-request-headers , http://stackoverflow.com/questions/20035101/no-access-control-allow-origin-header-is-present-on-the-requested-resource – guest271314 Mar 02 '16 at 22:27
  • What is the expected response ? Is `alert()` called using `js` at post ? – guest271314 Mar 02 '16 at 22:32
  • The `jqxhr.getAllResponseHeaders()` returns empty string. But it might be related to CORS since IE is showing different behavior. I'm going to need to test more. What a mess. The goal is to use a global error handler that can show meaningful messages. In this case it would be the 401 and or the `Access-Control-Allow-Origin`. – pretzelb Mar 02 '16 at 22:45
  • @pretzelb Using `stausCode` , you should be able to alert `"401 Unauthorized"` – guest271314 Mar 02 '16 at 22:54
  • I have not tested your sample with statusCode because in the documentation for ajaxSetup they `strongly recommend against using this API`. The focus of this question is to determine how to use `ajaxError` as a global handler. Either I'm using it incorrectly or this first test case involving CORS won't work. – pretzelb Mar 03 '16 at 12:10
  • @pretzelb fwiw, have not found that using `$.ajaxSetup()` causes issues, here. You could also pass the `statusCode` object to individual `$.ajax()` calls – guest271314 Mar 03 '16 at 12:15