jQuery ajax - Absolute URL's and error handling - javascript

Is it possible to catch the HTTP errors (like 404, 500, 504 etc) when we call an external webservice by specifying an absolute url?. (like setting the url: attribute of $.ajax call to have a url value as http://api.geonames.org/findNearbyPostalCodes.
Right now I'm unable to receive any errors although firebug is catching them and showing it in the console.
Can someone help?
Here is my code.
$.ajax({
type: 'GET',
url: "http://api.geonames.org/findNearbyPostalCodes",
data: '{"lat":47,"lng":"9","username":"demo"}',
dataType: 'json',
cache:false,
async:false,
statusCode:{
404: function(){
alert('Page not found');
},
500: function(){
alert('Page not found');
},
504: function(){
alert('Unknown host');
}
},
success: function(data){
alert(data);
}
error: function (xhr, exception, thrownError)
{
alert(xhr.status);
}
});

No, it is not possible with cross-domain (external) requests using only client-side code. This is because cross-domain requests rely on JSONP - ie, injecting a script tag that loads code from an external source. Unfortunately, the <script> element does not have anything like an onerror event.
You can handle errors with same-domain requests because these typically use XMLHttpRequest, which returns a lot of useful information like status codes and response headers.
Your best bet would be to use your local server as a proxy.

If using an absolute URL causes the domain to be different from the domain of your page (cross-domain request), then the only way to successfully execute an ajax call is to use JSONP which will cause the ajax library to use <script> tags for the cross-domain request instead of the more typical XMLHttpRequest used for same-domain requests.
You will not be able to intercept any sort of status codes from the loading of the cross-domain <script> tag.

In your case, you cannot check the status code (assuming you're not making the request from api.geonames.org).
jQuery will always return a "0" as the status if the request is cross-domain:
$.ajax({
type: 'GET',
url: 'http://someotherdomain.com/api/query',
dataType: 'json',
data: '{"first": 1, "second": 2}',
complete: function(response) { // the 'response' object has the status code
if (response.status == '200') {
// do something on success
} else if (response.status == '0') {
alert('Your request is cross-domain');
}
}
});
If the request happens to be within the same domain, you'll get a valid status code that you can check (the complete attribute of the $.ajax() function will run after any success or failure callbacks are run).

Related

Jquery ajax response not calling Success method

I am pretty much new to ajax and working on jquery ajax request. Ajax callback is not calling success method. Interaction is between cross-site domains.
My AJAX request looks like
$.ajax({
timeout: 20000,
url: 'test.com',
crossDomain: true,
dataType: 'jsonp',
success: function (data) {
console.log('callback success');
this._cache = data;
localStorage.token = data.access_token;
} });
There are no errors in this call.
This ajax request is not calling success function.Request is returning json data. it's just success method is not getting called.
This ajax request is not calling success function.
Get request is getting fired successfully. I can even trace the response in fiddler with 200 http response.For some reason success method is not getting called.
it's returning json object, which I've traced in fiddler
You're telling jQuery to expect a JSONP response, so it is trying to execute the JSON document as if it were a JavaScript script (because that is what JSONP is). This fails because it is not JSONP.
Either return JSONP instead of JSON or (assuming the server returns the correct Content-Type) remove dataType: 'jsonp',.
ok... I came here with the same problem... and when I read that specifying datatype:jsonp never calls success as a callback per #mondjunge from a comment above, it started me thinking about some behavior I saw earlier from my code and that maybe datatype:json might have the same behavior for what ever reason here too.
So after reading this page I took out my datatype declaration from my ajax request and my servlet returned the proper data payload, returned a 200, and jquery called the success function finally and modified my DOM.
All those steps happened except the last one until I removed my datatype from my ajax call. NOT what I was expecting!
Hopefully someone else can shed some light on why this happens... for now at least the few that don't lose their minds to this issue that find this post can do this in the mean time.
Check if your ajax is executed
Check it's status. If response code is != 200, than you should add error method also, for error handling.
Try this:
$.ajax({
timeout: 20000,
url: 'test.com',
method: 'GET',
crossDomain: true,
dataType: 'jsonp',
success: function (data) {
console.log('callback success');
this._cache = data;
localStorage.token = data.access_token;
},
error: function(xhr, error){
console.debug(xhr); console.debug(error);
},
});

Error handling cross domain jquery ajax call

I am performing one cross domain get operation as shown below.
$.ajax({
type: "GET",
url: "http://localhost:65249/api/item/get",
data: {
searchText: "test"
},
dataType: "jsonp",
async: false,
success: function (results) {
alert(results);
},
error: function (jqXHR, error, errorThrown) {
if (jqXHR.status && jqXHR.status == 401) {
alert("Unauthorized request");
} else if (jqXHR.status && jqXHR.status == 404) {
alert("The requested page not found");
}
}
});
But success or error block is not getting called after request is completed. when i debug java script in developer console i am receiving error but error block of javascript is not getting called.
GET http://localhost:65249/api/item/getallproducts?callback=jQuery182028460139059461653_1396510235829&searchText=test&_=1396510674779 401 (Unauthorized)
Unfortunately, if you are using JSONP, all requests that return an error fail silently. This is because JSONP uses a script tag instead of XmlHttpRequest. If you want errors to fire, you need to use XHR with CORS. CORS needs to be configured on the server side, and it works client side only in IE 10+.
error dont work on corss domain calls, see jquery doku. for error:
Note: This handler is not called for cross-domain script and
cross-domain JSONP requests.
Take a look at this answer:
JSONP request error handling

jQuery AJAX request getting response but no callbacks are fired

I have code as such:
$.ajax({
method: "GET",
url: page,
dataType: 'html',
data:data,
success: function(data){
console.log(data);
},
error: function(){
console.log('error');
}
});
Using either Chrome or Firefox's debugger I can see that the request is successful with a response of 200 OK and the response contains the expected data.
My problem is, however, that no callbacks fire whatsoever. "Success" does not fire nor does "Error". Furthermore, no deferred methods fire either, such as "done", "then", or "always".
I've been trying to trouble shoot this for the past few hours to no avail. I'm at a total loss. I've also tried using methods such as "$.get" with the same result.
In short, I'm getting the response, but the code in jQuery is not firing any callbacks and all without any visible errors in the console.
One thing I see wrong in your code is that:
method: "GET",
should be:
type: "GET",
I don't see any documented property for method in the jQuery doc. The type property is supposed to default to "GET" so this may not be the only thing wrong here.
In addition, there are cases where the error callback will not be called even if the ajax call fails (in cross-domain requests). From the jQuery doc for the error callback:
This handler is not called for cross-domain script and cross-domain JSONP requests.
This is because jQuery is expecting the server to send back a particular form of javascript and if the server doesn't do what is expected, then jQuery never knows when the request comes back and can't process it.
In these cases, you often have to figure out what might be going wrong from looking at the network trace in the debugger.
Other things to check to make sure you aren't accidentally cross domain:
Make sure the domain/subdomain are exactly the same between ajax call and the page. For example, one common mistake is for one to have www. on it and the other not.
Make both page and ajax URL are both same http or https.
If using a non-standard port number, make sure both page and ajax URL are using the same port.
The following code works. Also note that AJAX will not work with cross site scripting.
If you want to get the error you can print the "errorThrown"
<script>
$(document).ready(function () {
$('#getLink').on("click", function () {
var url = $("#myUrl");
alert(url.val());
$.ajax({
type: "GET",
url: url.val(),
dataType: 'html',
success: function (data, textStatus, xhr) {
$("#data").text(textStatus);
},
error: function (data,textStatus, errorThrown){
$("#data").text(errorThrown);
}
});
});
});
</script>
<input id="myUrl" name="myURL" type="text" value="http://localhost:35460/Home/TestPage.cshtml" />
<input type="button" value="getLink" id="getLink">
<span id="data"></span>

Salesforce - success handler for $.ajax call

I have a form that I have been submitting to Salesforce with standard form submit action. By default, you can tell Salesforce to redirect you to a given URL after the POST has completed.
I no longer wish to be redirected since I have other activities on the form page. No problem, my page is already using jQuery so I can use the handy $.ajax utility like this:
$('#wrapper').on('click', '#formsubmit', function(e) {
e.preventDefault();
var formData = $('#subForm').serialize();
$.ajax({
type: "POST",
url: "https://www.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8",
data: formData,
success: function() {
console.log('success!'); // or not!
},
error:function (xhr, ajaxOptions, thrownError){
console.log(xhr.status); // 0
console.log(thrownError); // empty
}
});
});
In my misguided brain, I imagined that Salesforce would return my good ol' redirect, which would count as a "success" that I can just discard/ignore. Misguided indeed!
I can see a 200 OK result (which usually means "success") but the success callback isn't tripped.
The lead is added to the Salesforce database
Inspecting the content of what's returned shows zero; there is no content in the response.
The error callback IS being tripped (despite the 200 OK) but maybe due to intentionally not redirecting it is seen as a "resource not available"? (therefore my status code is 0, and there is no content in the thrownError?).
Any advice on identifying this as a successful POST so that I can trigger additional actions in a callback? I don't want to TOTALLY ignore the response, or I could end up in a scenario in which I'm acting on a failed POST as if it was successful. I need to capture the success somehow.
It occurred to me that it could be a cross-site scripting issue as well, but since the application doesn't exchange data in JSONP, I'm not sure how to get around that (and I'm not sure how to identify it in the first place).
Few things here:
1) The redirect response being sent by salesforce's API is most likely being interpreted as an error code.
2) The response code of the subsequent page (after the redirect) is 200 OK, from the sound of it.
3) It is not possible to do a POST request using JSONP. This is a limitation of JSONP; which is not actually an AJAX request, but an HTTP GET request wrapped inside of a dynamically generated script tag. Also, JSONP only works if the request yields an HTTP response of 200 OK.
I would recommend using your own server-side intermediary to handle your AJAX POST request. This will act as a proxy between your front-end app and salesforce's API. This will also allow you to better control the response being sent to your app.
var formData = $('#subForm').serialize();
var response = $.ajax({
type: "POST",
url: "https://www.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8",
data: formData,
success: function() {
console.log('success!'); // or not!
},
error:function (xhr, ajaxOptions, thrownError){
console.log(xhr.status); // 0
console.log(thrownError); // empty
}
}).responseText;
where var response will contain the return value from your ajax call

jQuery $.getJSON not working

I am try to get a URL from a one server and using that URL to get contents of another server.
$.ajax({url : 'http://localhost:8080/geturl.jsp?A=1&B=2,C=3',
success : function (data)
{
alert(data);
$.getJSON(data, function (mydata)
{
alert(mydata);
});
},
error : function (data, status, xhr)
{
}
});
I know that we cannot make cross-domain requests in through ajax call, thats why i am using getJSON, i have the following problems
When i simply pass the data to the url part of getJSON (as shown in the code), the alert-box show the correct URL but no get request is being performed ( get requests were monitored from FireBug).
When a hard-code the data to be "http://www.google.com" then the get request is being performed but the no response comes, although the response headers comes and response code is 200 (but it was marked as RED in the Firebug (Dont know why :( )
When I tries to fetch a webpage host in localhost domain, then it is fetched correctly although the response was not JSON.
I have the following doubts
If the getJSON function accecpts only JSON objects as reponse then why no error came when perform above 3.
Whats the correct code to perform my the required functionality.
Suggestions to what happened in each case
Thanks in advance for the answers :)
The getJSON function can only be used across domains to fetch JSONP.
It does not magically evade any security restrictions.
http://api.jquery.com/jQuery.ajax/
This should be a working example for jsonp:
var request = jQuery.ajax(
{
url: "http://Your url",
success: function (data) { console.log('success!'); console.log(data); },
error: function (data) { console.log('error!'); console.log(data); },
dataType: "jsonp",
type: "GET",
data: { key: 'value' }
});

Categories

Resources