When an AJAX request is submitted to a site, server-side errors are easily handled with the jQuery promise approach. .done(), .fail(), etc. However for some requests (e.g. to an invalid site or one that doesn't accept cross-origin requests), an exception occurs immediately as the call is made. Here's an example of one error in the console:
XMLHttpRequest cannot load http://someotherserver/api/blahblah. Origin
http://localhost:52625 is not allowed by Access-Control-Allow-Origin.
Yes, I know about CORS...that's not the issue. What I'm actually doing is trying a web api call to test if the server IP/name is correct
I'm aware of the error option in the jQuery request syntax:
$.ajax({
url: remoteURL,
type: 'GET',
error: function (err) {
console.log("AJAX error in request: " + JSON.stringify(err, null, 2));
}
}).etc.etc.
The error is handled here, but exceptions are still logged in the console. It seemed reasonable to wrap the above in a try-catch block, but that doesn't seem to help.
I've found this question, but the solution involves hacking the jQuery code. Surely there's a better way to catch these errors and not clog up the console logs??
try this:
$.ajax({
url: remoteURL,
type: 'GET',
error: function (err) {
console.log("AJAX error in request: " + JSON.stringify(err, null, 2));
}
}).always(function(jqXHR, textStatus) {
if (textStatus != "success") {
alert("Error: " + jqXHR.statusText);
}
});
XHR Listener:
$.ajax({
url: remoteURL,
type: 'GET',
xhr: function(){
var xhr = new window.XMLHttpRequest();
xhr.addEventListener("error", function(evt){
alert("an error occured");
}, false);
xhr.addEventListener("abort", function(){
alert("cancelled");
}, false);
return xhr;
},
error: function (err) {
console.log("AJAX error in request: " + JSON.stringify(err, null, 2));
}
});
You can use web developer console in google chrome. Press F12. And use Networks tab for checking response, And for JavaSvript and jQuery and Ajax errors you can use Console tab. :)
Try this by adding to your ajax function :
error: function(XMLHttpRequest, textStatus, errorThrown) {
alert(errorThrown);
Related
AJAX error is being returned as Success. How to return JSON error from ASP.NET MVC? Could you tell me what I'm doing wrong? Thank you.
[HttpPost]
public JsonResult Register(int EventID)
{
try
{
// code
return Json(new { success = true, message = "Thank you for registering!" });
}
catch (Exception ex)
{
return Json(new { success = false, message = ex.Message });
}
}
$.ajax({
url: "#Url.Action("Register", "Home")",
type: "post",
dataType: "json",
contentType: "application/json",
data: JSON.stringify(postData),
success: function(data) {
},
error: function (data) {
}
});
The error function gets executed only when the HTTP Response Code is not HTTP 200 Ready. You handle the error in the server-side and return proper response, which will be picked up by success function in the AJAX call. Instead, use the status variable in your JSON and handle it on the client side:
success: function(data) {
if (typeof data == "string")
data = JSON.parse(data);
if (data.success) {
// Code if success.
} else {
// Code if error.
}
},
From the docs (scroll down to the error section):
A function to be called if the request fails. The function receives three arguments: The jqXHR (in jQuery 1.4.x, XMLHttpRequest) object, a string describing the type of error that occurred and an optional exception object, if one occurred. Possible values for the second argument (besides null) are "timeout", "error", "abort", and "parsererror". When an HTTP error occurs, errorThrown receives the textual portion of the HTTP status, such as "Not Found" or "Internal Server Error." As of jQuery 1.5, the error setting can accept an array of functions. Each function will be called in turn. Note: This handler is not called for cross-domain script and cross-domain JSONP requests. This is an Ajax Event.
The Ajax error method is hit only when you get a Yellow Screen Error in the server side. In your scenario you are handling the error using try catch and returning a valid response. So this is not considered as a error but a valid response. Remove your try catch so that Ajax will pick up the error event, else if you want to show the actual error message from server then you can use the success property to decide if the response was a success or a error , its similar to what Praveen has already posted in his answer.
success: function(data) {
if (data.success) { //as you are passing true/false from server side.
// Code if success.
} else {
// Code if error.
}
},
I've got an AJAX request which pulls the data from the form and POSTs it to an API. The weird thing is it works perfectly fine on localhost but fails silently when I upload to remote server. And I mean silently: the response code is blank, there's nothing in the logs. I've checked on Firefox and Chrome. jQuery is loaded, function is firing properly. The code is below:
function send() {
console.log("preparing");
var beacon = {
beaconID: $("#beaconID").val(),
name:$("#beaconName").val(),
campaignID:$("#campaignID").val(),
clientID:$("#clientID").val()
}
console.log("payload:");
console.log(beacon);
$.ajax({
type: 'POST',
url: '../beaconAPI/index.php/createBeacon',
data: JSON.stringify(beacon),
contentType: "application/json; charset=utf-8",
traditional: true,
success: function (response) {
console.log("done:");
console.log(response);
},
error: function(jqXHR, textStatus, errorThrown) {
console.log(JSON.stringify(jqXHR));
console.log("AJAX error: " + textStatus + ' : ' + errorThrown);
}
});
}
From the comments you posted
10:33:21.046 "{"readyState":0,"responseText":"","status":0,
"statusText":"error"}" addBeacon.html:34 10:33:21.046 "AJAX error: error : "
A status code of zero means one of two things:
You are running off file protocol
The page refreshed as Ajax call is made
Since you said this is on production, sounds like it is a case of #2.
So you need to cancel the action that is causing the page to refresh. Since you do not show how you call send, here is some basic ways of cancelling the action.
onclick="send(); return false"
onsubmit="send(); return false"
$("#foo").on("click", function(e) {
send();
e.preventDefault();
});
How can i capture the 500 error message using jquery? I want to keep on checking for the 500 error message for sometime until it changes and time out after 50 sec.
I used the code below to try to capture and check the 500 error message but it doesnt seem to catch the 500 error message. I can see it in the firebug
$.ajax({
statusCode: {
500: function() {
alert(" 500 data still loading");
console.log('500 ');
}
}
});
Dispite the accepted answer mentioned by #Danny, you can also do this in newer versions of jQuery.
var xhr = $.ajax({
url: "somewhere"
});
xhr.fail(function(xhr, textStatus, error) {
// Error handling stuff here ...
});
See Deferred Object.
Are you missing url in $.ajax like the one below
$.ajax({
url: "/path to page",
statusCode: {
500: function() {
alert(" 500 data still loading");
console.log('500 ');
}
}
});
You can check the status in error of ajax post please check the below code.
$.ajax({
.....
success: function (data) {
},
complete: function (XMLHttpRequest, textStatus) {
},
error: function (e, status) {
if (e.status == 404)
alert("404 error");
}
});
Thanks
Okay, I do use firebug to determine when a function is not defined in Dev. What I would like to do in production is show a modal window saying an error has been received which would then redirect them to another page upon click. Not so easy.
Please understand that this function does work and the component that is called works. I am going to misspell the function call on purpose to demonstrate the error I am not receiving thru the jquery ajax function.
I am using .ajaxSetup to set up the default options for several ajax functions that will be running asynch:
$.ajaxSetup({
type: "POST",
dataType: "json",
url: "DMF.cfc",
data: {
qID: 1,
returnFormat: "json"
},
beforeSend: function() {
$('#loadingmessage').fadeIn(); // show the loading message.
},
complete: function() {
$('#loadingmessage').fadeOut(); // show the loading message.
}
}); //end AjaxSetup
The actual ajax call is:
$.ajax({
data: {
method: 'getCurrentIssues'
},
success: function(response) {
nsNewDebtshowDebtIssues(response);
},//end success function
error: function(jqXHR, exception) {
alert("Error running nsNewDebt.showDebtIssues");
}
}) //end getCurrentIssues Ajax Call
The error I forced is that the method run in the success function should actually be nsNewDebt.showDebtIssues. Firebug correctly displays in console the error nsNewDebtshowDebtIssues is not defined but the actual error message for the ajax call does not run, so if an enduser was running the page it would appear the page was hung.
So, In summary I want to know how to track when such an error occurs, preferrable to place in the error section of the .ajaxSsetup but if neccessary in each .ajax call.
It is not an ajax error, so you cannot handle it from the ajaxError method.
You should do a try/catch in the success method.
success: function(response) {
try {
nsNewDebtshowDebtIssues(response);
} catch (ex) {
//exception occured
//alert("Error running nsNewDebt.showDebtIssues");
alert( ex.message + '\n\tin file : ' + ex.fileName + '\n\t at line : ' + ex.lineNumber);
}
}
Before making the call, you can do:
if(typeof nsNewDebtshowDebtIssues == 'function') {
// .. call it ..
}
Well, the error actually occurs after the AJAX call has succeeded (since it comes from your success handler), so the error handler indeed won't be called.
If you want to use the same handler for actual AJAX request errors and for further errors originating from your success handler, you can define a named function and use it both as your error handler and from a try/catch block in your success handler:
function handleError(jqXHR, status, exception)
{
alert("Error running request.");
// Or print something from 'jqXHR', 'status' and 'exception'...
}
$.ajax({
data: {
method: "getCurrentIssues"
},
success: function(response, status, jqXHR) {
try {
nsNewDebtshowDebtIssues(response);
} catch (x) {
handleError(jqXHR, status, x);
}
},
error: handleError
});
I'm building a RESTful web api with asp.net mvc, which returns pure json data. On my client, I'm using backbone.js to communicate to it.
My question is, how do I capture the message in javascript? For eg. What if a user has no permission to delete or there was no item matching the id? I've been told to throw http errors instead of custom json.
So my code would be:
[HttpDelete]
public ActionResult Index(int id)
{
if (id == 1)
{
throw new HttpException(404, "No user with that ID");
}
else if (id == 2)
{
throw new HttpException(401, "You have no authorization to delete this user");
}
return Json(true);
}
How do I access the message in my javascript callback? The callback would look like:
function (model, response) {
alert("failed");
//response.responseText would contain the html you would see for asp.net
}
I do not see message i threw in the exception anywhere at all in the data that was returned from the server.
You should use the error callback on the client. The success callback is triggered only when the request succeeds:
$.ajax({
url: '/home/index',
type: 'DELETE',
data: { id: 1 },
success: function (result) {
alert('success'); // result will always be true here
},
error: function (jqXHR, textStatus, errorThrown) {
var statusCode = jqXHR.status; // will equal to 404
alert(statusCode);
}
});
Now there is a caveat with 401 status code. When you throw 401 HTTP exception from the server, the forms authentication module intercepts it and automatically renders the LogIn page and replaces the 401 status code with 200. So the error handler will not be executed for this particular status code.
I just answered this in my question What is the point of HttpException in ASP.NET MVC, but you can actually get that string if you use the HttpStatusCodeResult like this:
In your controller:
return new HttpStatusCodeResult(500,"Something bad happened")
And you can access "Something bad happened" using, say, jQuery $.ajax() like this:
$.ajax: {
url: "#Url.Action("RequestsAdminAjax", "Admin")",
type: "POST",
data: function(data) { return JSON.stringify(data); },
contentType: "application/json; charset=utf-8",
error: function (xhr, textStatus,errorThrown) {
debugger;
toggleAlert('<strong>Error: </strong>Unable to load data.', 'alert alert-danger');
}
},
and errorThrown will contain "Something bad happened".
HTH.