Best practice to detect if service is available - javascript

I need to detect if my service is available in the moment.
But, for some reason, I receive success in ajax() function when I try to reach some of the service methods even if the service is turned off.
I get an html page with 404 message as data in the success field.
My best guess is to use typeof(data) and compare it with string type.
But I think there must be a better solution.
Nothing special just $.ajax()
$.ajax({
url: '../Services/Service.svc/getItems',
data: {},
error: function (error) {
},
success: function (data, status, xhr) {
},
datatype: "json",
});

Going with the info you provided.
If you are in control of the service (ie: you built it) then you could make the webserver return a 503 code when the service is unavailable. This is something the webserver should do when your service is down.
If not, then you need to check for the 404 error code instead that you are receiving right now and handle it gracefully in your code.
I'm assuming you are using jQuery for the client since you refer to the ajax() call. Here is a basic example to check the errorcode in the fail callback:
var serviceRequest = $.ajax(...);
serviceRequest.done(function(returnedData) {
// Service is active and returning data.
});
serviceRequest.fail(function (xhr) {
if(xhr.status == 404) {
// handle this.
}
if(xhr.status == 503) {
// handle this.
}
});
Why you are receiving a 404 and hitting the success callback is something I have never seen before.

Related

.fail() fails to execute when ajax request is not successful [duplicate]

Is it possible to catch an error when using JSONP with jQuery? I've tried both the $.getJSON and $.ajax methods but neither will catch the 404 error I'm testing. Here is what I've tried (keep in mind that these all work successfully, but I want to handle the case when it fails):
jQuery.ajax({
type: "GET",
url: handlerURL,
dataType: "jsonp",
success: function(results){
alert("Success!");
},
error: function(XMLHttpRequest, textStatus, errorThrown){
alert("Error");
}
});
And also:
jQuery.getJSON(handlerURL + "&callback=?",
function(jsonResult){
alert("Success!");
});
I've also tried adding the $.ajaxError but that didn't work either:
jQuery(document).ajaxError(function(event, request, settings){
alert("Error");
});
Here's my extensive answer to a similar question.
Here's the code:
jQuery.getJSON(handlerURL + "&callback=?",
function(jsonResult){
alert("Success!");
})
.done(function() { alert('getJSON request succeeded!'); })
.fail(function(jqXHR, textStatus, errorThrown) { alert('getJSON request failed! ' + textStatus); })
.always(function() { alert('getJSON request ended!'); });
It seems that JSONP requests that don't return a successful result never trigger any event, success or failure, and for better or worse that's apparently by design.
After searching their bug tracker, there's a patch which may be a possible solution using a timeout callback. See bug report #3442. If you can't capture the error, you can at least timeout after waiting a reasonable amount of time for success.
Detecting JSONP problems
If you don't want to download a dependency, you can detect the error state yourself. It's easy.
You will only be able to detect JSONP errors by using some sort of timeout. If there's no valid response in a certain time, then assume an error. The error could be basically anything, though.
Here's a simple way to go about checking for errors. Just use a success flag:
var success = false;
$.getJSON(url, function(json) {
success = true;
// ... whatever else your callback needs to do ...
});
// Set a 5-second (or however long you want) timeout to check for errors
setTimeout(function() {
if (!success)
{
// Handle error accordingly
alert("Houston, we have a problem.");
}
}, 5000);
As thedawnrider mentioned in comments, you could also use clearTimeout instead:
var errorTimeout = setTimeout(function() {
if (!success)
{
// Handle error accordingly
alert("Houston, we have a problem.");
}
}, 5000);
$.getJSON(url, function(json) {
clearTimeout(errorTimeout);
// ... whatever else your callback needs to do ...
});
Why? Read on...
Here's how JSONP works in a nutshell:
JSONP doesn't use XMLHttpRequest like regular AJAX requests. Instead, it injects a <script> tag into the page, where the "src" attribute is the URL of the request. The content of the response is wrapped in a Javascript function which is then executed when downloaded.
For example.
JSONP request: https://api.site.com/endpoint?this=that&callback=myFunc
Javascript will inject this script tag into the DOM:
<script src="https://api.site.com/endpoint?this=that&callback=myFunc"></script>
What happens when a <script> tag is added to the DOM? Obviously, it gets executed.
So suppose the response to this query yielded a JSON result like:
{"answer":42}
To the browser, that's the same thing as a script's source, so it gets executed. But what happens when you execute this:
<script>{"answer":42}</script>
Well, nothing. It's just an object. It doesn't get stored, saved, and nothing happens.
This is why JSONP requests wrap their results in a function. The server, which must support JSONP serialization, sees the callback parameter you specified, and returns this instead:
myFunc({"answer":42})
Then this gets executed instead:
<script>myFunc({"answer":42})</script>
... which is much more useful. Somewhere in your code is, in this case, a global function called myFunc:
myFunc(data)
{
alert("The answer to life, the universe, and everything is: " + data.answer);
}
That's it. That's the "magic" of JSONP. Then to build in a timeout check is very simple, like shown above. Make the request and immediately after, start a timeout. After X seconds, if your flag still hasn't been set, then the request timed out.
I know this question is a little old but I didn't see an answer that gives a simple solution to the problem so I figured I would share my 'simple' solution.
$.getJSON("example.json", function() {
console.log( "success" );
}).fail(function() {
console.log( "error" );
});
We can simply use the .fail() callback to check to see if an error occurred.
Hope this helps :)
If you collaborate with the provider, you could send another query string parameter being the function to callback when there's an error.
?callback=?&error=?
This is called JSONPE but it's not at all a defacto standard.
The provider then passes information to the error function to help you diagnose.
Doesn't help with comm errors though - jQuery would have to be updated to also callback the error function on timeout, as in Adam Bellaire's answer.
Seems like this is working now:
jQuery(document).ajaxError(function(event, request, settings){
alert("Error");
});
I use this to catch an JSON error
try {
$.getJSON(ajaxURL,callback).ajaxError();
} catch(err) {
alert("wow");
alert("Error : "+ err);
}
Edit: Alternatively you can get the error message also. This will let you know what the error is exactly. Try following syntax in catch block
alert("Error : " + err);
Mayby this works?
.complete(function(response, status) {
if (response.status == "404")
alert("404 Error");
else{
//Do something
}
if(status == "error")
alert("Error");
else{
//Do something
}
});
I dont know whenever the status goes in "error" mode. But i tested it with 404 and it responded
you ca explicitly handle any error number by adding this attribute in the ajax request:
statusCode: {
404: function() {
alert("page not found");
}
}
so, your code should be like this:
jQuery.ajax({
type: "GET",
statusCode: {
404: function() {
alert("page not found");
}
},
url: handlerURL,
dataType: "jsonp",
success: function(results){
alert("Success!");
},
error: function(XMLHttpRequest, textStatus, errorThrown){
alert("Error");
}
});
hope this helps you :)
I also posted this answer in stackoverflow - Error handling in getJSON calls
I know it's been a while since someone answerd here and the poster probably already got his answer either from here or from somewhere else. I do however think that this post will help anyone looking for a way to keep track of errors and timeouts while doing getJSON requests. Therefore below my answer to the question
The getJSON structure is as follows (found on http://api.jqueri.com):
$(selector).getJSON(url,data,success(data,status,xhr))
most people implement that using
$.getJSON(url, datatosend, function(data){
//do something with the data
});
where they use the url var to provide a link to the JSON data, the datatosend as a place to add the "?callback=?" and other variables that have to be send to get the correct JSON data returned, and the success funcion as a function for processing the data.
You can however add the status and xhr variables in your success function. The status variable contains one of the following strings : "success", "notmodified", "error", "timeout", or "parsererror", and the xhr variable contains the returned XMLHttpRequest object
(found on w3schools)
$.getJSON(url, datatosend, function(data, status, xhr){
if (status == "success"){
//do something with the data
}else if (status == "timeout"){
alert("Something is wrong with the connection");
}else if (status == "error" || status == "parsererror" ){
alert("An error occured");
}else{
alert("datatosend did not change");
}
});
This way it is easy to keep track of timeouts and errors without having to implement a custom timeout tracker that is started once a request is done.
Hope this helps someone still looking for an answer to this question.

Ajax fails 5% of time, response is "error"

I'm using jQuery to handle Ajax-calls.
I've noticed that, about 5% off the time, the ajax call fails. To make sure I get a good understanding of what's going wrong, I use this code:
$.ajax({
type:'POST',
url:'somepage.php',
data:{somedata:somedata},
success:function (data) {
var IS_JSON = true;
try
{
var newdata = jQuery.parseJSON(data);
}
catch(err)
{
IS_JSON = false;
}
if(IS_JSON)
{
//this is the part where a correct response is handled
}
else
{
//In case somepage.php gives a php-error, I put the exact error (=data) in the error-table at error.php.
window.location = "error.php?errorstring="+data;
}
},
error:function (XMLHttpRequest, textStatus, errorThrown) {
//In case the ajax errors, I store the response (timeout, error, ...) in the database at error.php
window.location = "error.php?errorstring="+textStatus;
}
});
"Good" responses contain JSON, which I parse. If it's not JSON (for example just raw text from an php error) I don't try to parse it, but store the error in my database.
I would understand errors containing php errors that occured on somepage.php (since it's quiet a large page), but I'm supprised that the main errors I get, are errors of the ajax failing. The response data is just "error".
Anyone knows what the cause could be? What causes ajax-calls to fail? It's not a timeout, and it's also nothing like that somepage.php wasn't found or something. It's also not an error on somepage.php, since in that case, the Ajax-call would be successful, and the php-error would be logged in my database.
Edit: I used this obfuscator to make the script a little harder to read... Don't know if this could be causing the errors...
You should set dataType: 'json' in your ajax call. Coz if your not setting this up and your expecting a json result, the result will be treated as 'string' by default.

$.post is not working (anywhere)! Why?

My calls to $.post are not working all over my code. I'm not sending the request to other domains and, actually, I'm doing everything localhosted. My localhost alias was automatically defined by the Mac OS X 10.8 as ramon.local and I'm requesting from http://ramon.local/linkebuy_0.7/resourceX to http://ramon.local/linkebuy_0.7/resourceY. There are no errors on Chrome's console.
The server side doesn't receive the request and I can check it by accessing directly from the browser (typing the URL).
It's not just one call that is not working, none of them are. They were all working days ago and I'm suspicious that I accidentally changed something on my local settings. What could it be?
Here's an example of what I'm facing:
$.post(
<<CORRECT URL INSIDE THE DOMAIN>>,
{},
function(response) {
console.log('THIS SHOULD BE PRINTED ON CONSOLE');
alert('THIS SHOULD BE POPPED UP');
}
);
I don't get the alert, neither the console message while running the code above. So I tried the following:
$.support.cors = true;
$.ajax({
url: "http://ramon.local/linkebuy_0.7",
dataType: "json",
type: "GET",
crossDomain: true,
success: function (data) {
console.log(data);
},
error: function (xhr, status, error) {
alert(error + " - " + status);
}
});
I just came with $.support.cors = true; and crossDomain: true to check if it was a cross domain issue. So I was alerted No Transport - error same way as before.
What can I do to solve that?
Thanks in advance.
Try this and see if you are getting any alert:
// Assign handlers immediately after making the request,
// and remember the jqxhr object for this request
var jqxhr = $.post("your url", function() {
alert("success");
}).success(function() {
alert("second success");
}).error(function() {
alert("error");
}).complete(function() {
alert("complete");
});
// perform other work here ...
// Set another completion function for the request above
jqxhr.complete(function() {
alert("second complete");
});​
Well, I solved the problem in a very strange way.
I deleted the JQuery file and downloaded it again, replacing the old one. Happens it worked out.
So, if you're:
Making AJAX requests that are not cross-domain;
Using JQuery for it (e.g. $.post, $.get, etc);
Getting No Transport AJAX error
Then re-download and replace you're JQuery source.
Else, if you're making cross-domain requests (not this case), then look for JSONP and try to set $.support.cors = true; at the beginning of you're code.
Thanks everyone for the comments and answers.

Calling a webservice using JQuery

I am using this code from http://www.joe-stevens.com/2010/01/04/using-jquery-to-make-ajax-calls-to-an-asmx-web-service-using-asp-net/
function callWebService(address) {
var result;
$("#result").addClass("loading");
$.ajax({
type: "POST",
url: address,
data: "{}",contentType: "application/json; charset=utf-8",
dataType: "json",
success: Success,
error: Error
});
}
function Success(data, status) {
$("#result").removeClass("loading");
$("#result").html(data.d);
alert("Success");
}
function Error(request, status, error) {
$("#result").removeClass("loading");
$("#result").html(request.statusText);
alert("Error");
}
I don't understand what is wrong with this code. It keeps returning "Error"
Also make sure that the service URL that you're trying to access is in the same domain as your site. AJAX calls won't succeed if you cross domains, since browsers subject AJAX calls to the same domain policy. Can you also include the URL you're trying to access?
If you're trying to access a resource at a different domain, you may want to consider a JSONP request instead. See the jQuery AJAX documentation for a discussion of how to use JSONP.
I think if you combine knowing the URL you're trying to access along with Justin and mohlsen's suggestions, I think we can help.
Your code looks fine at first glance.
I recommend you use FireBug to attempt to isolate the problem further, as it will allow you to see the actual HTTP requests, POSTed data, etc...
A few suggestions based on some code I have doing this. But as others have said, make sure to manually look at the data going out and coming back. Your link references asp.net webservice, is that what you are calling since you didn't mention it.
Make sure the "address" url is of the form /location/page.asmx/methodname
You might need to pass the data to the success method in the call
success: function(msg) {
//msg is a json object, .d is the data field returned by asp.net
if (msg.d.length > 0)
ProcessData(msg.d);
else
HandleError('No data was returned.');
},
error: function() {
HandleError('There was a problem calling the webservice.');
}

How to manage a redirect request after a jQuery Ajax call

I'm using $.post() to call a servlet using Ajax and then using the resulting HTML fragment to replace a div element in the user's current page. However, if the session times out, the server sends a redirect directive to send the user to the login page. In this case, jQuery is replacing the div element with the contents of the login page, forcing the user's eyes to witness a rare scene indeed.
How can I manage a redirect directive from an Ajax call with jQuery 1.2.6?
I read this question and implemented the approach that has been stated regarding setting the response HTTP status code to 278 in order to avoid the browser transparently handling the redirects. Even though this worked, I was a little dissatisfied as it is a bit of a hack.
After more digging around, I ditched this approach and used JSON. In this case, all responses to AJAX requests have the status code 200 and the body of the response contains a JSON object that is constructed on the server. The JavaScript on the client can then use the JSON object to decide what it needs to do.
I had a similar problem to yours. I perform an AJAX request that has 2 possible responses: one that redirects the browser to a new page and one that replaces an existing HTML form on the current page with a new one. The jQuery code to do this looks something like:
$.ajax({
type: "POST",
url: reqUrl,
data: reqBody,
dataType: "json",
success: function(data, textStatus) {
if (data.redirect) {
// data.redirect contains the string URL to redirect to
window.location.href = data.redirect;
} else {
// data.form contains the HTML for the replacement form
$("#myform").replaceWith(data.form);
}
}
});
The JSON object "data" is constructed on the server to have 2 members: data.redirect and data.form. I found this approach to be much better.
I solved this issue by:
Adding a custom header to the response:
public ActionResult Index(){
if (!HttpContext.User.Identity.IsAuthenticated)
{
HttpContext.Response.AddHeader("REQUIRES_AUTH","1");
}
return View();
}
Binding a JavaScript function to the ajaxSuccess event and checking to see if the header exists:
$(document).ajaxSuccess(function(event, request, settings) {
if (request.getResponseHeader('REQUIRES_AUTH') === '1') {
window.location = '/';
}
});
No browsers handle 301 and 302 responses correctly. And in fact the standard even says they should handle them "transparently" which is a MASSIVE headache for Ajax Library vendors. In Ra-Ajax we were forced into using HTTP response status code 278 (just some "unused" success code) to handle transparently redirects from the server...
This really annoys me, and if someone here have some "pull" in W3C I would appreciate that you could let W3C know that we really need to handle 301 and 302 codes ourselves...! ;)
The solution that was eventually implemented was to use a wrapper for the callback function of the Ajax call and in this wrapper check for the existence of a specific element on the returned HTML chunk. If the element was found then the wrapper executed a redirection. If not, the wrapper forwarded the call to the actual callback function.
For example, our wrapper function was something like:
function cbWrapper(data, funct){
if($("#myForm", data).length > 0)
top.location.href="login.htm";//redirection
else
funct(data);
}
Then, when making the Ajax call we used something like:
$.post("myAjaxHandler",
{
param1: foo,
param2: bar
},
function(data){
cbWrapper(data, myActualCB);
},
"html"
);
This worked for us because all Ajax calls always returned HTML inside a DIV element that we use to replace a piece of the page. Also, we only needed to redirect to the login page.
I like Timmerz's method with a slight twist of lemon. If you ever get returned contentType of text/html when you're expecting JSON, you are most likely being redirected. In my case, I just simply reload the page, and it gets redirected to the login page. Oh, and check that the jqXHR status is 200, which seems silly, because you are in the error function, right? Otherwise, legitimate error cases will force an iterative reload (oops)
$.ajax(
error: function (jqXHR, timeout, message) {
var contentType = jqXHR.getResponseHeader("Content-Type");
if (jqXHR.status === 200 && contentType.toLowerCase().indexOf("text/html") >= 0) {
// assume that our login has expired - reload our current page
window.location.reload();
}
});
Use the low-level $.ajax() call:
$.ajax({
url: "/yourservlet",
data: { },
complete: function(xmlHttp) {
// xmlHttp is a XMLHttpRquest object
alert(xmlHttp.status);
}
});
Try this for a redirect:
if (xmlHttp.code != 200) {
top.location.href = '/some/other/page';
}
I just wanted to share my approach as this might it might help someone:
I basically included a JavaScript module which handles the authentication stuff like displaying the username and also this case handling the redirect to the login page.
My scenario: We basically have an ISA server in between which listens to all requests and responds with a 302 and a location header to our login page.
In my JavaScript module my initial approach was something like
$(document).ajaxComplete(function(e, xhr, settings){
if(xhr.status === 302){
//check for location header and redirect...
}
});
The problem (as many here already mentioned) is that the browser handles the redirect by itself wherefore my ajaxComplete callback got never called, but instead I got the response of the already redirected Login page which obviously was a status 200. The problem: how do you detect whether the successful 200 response is your actual login page or just some other arbitrary page??
The solution
Since I was not able to capture 302 redirect responses, I added a LoginPage header on my login page which contained the url of the login page itself. In the module I now listen for the header and do a redirect:
if(xhr.status === 200){
var loginPageRedirectHeader = xhr.getResponseHeader("LoginPage");
if(loginPageRedirectHeader && loginPageRedirectHeader !== ""){
window.location.replace(loginPageRedirectHeader);
}
}
...and that works like charm :). You might wonder why I include the url in the LoginPage header...well basically because I found no way of determining the url of GET resulting from the automatic location redirect from the xhr object...
I know this topic is old, but I'll give yet another approach I've found and previously described here. Basically I'm using ASP.MVC with WIF (but this is not really important for the context of this topic - answer is adequate no matter which frameworks are used. The clue stays unchanged - dealing with issues related to authentication failures while performing ajax requests).
The approach shown below can be applied to all ajax requests out of the box (if they do not redefine beforeSend event obviously).
$.ajaxSetup({
beforeSend: checkPulse,
error: function (XMLHttpRequest, textStatus, errorThrown) {
document.open();
document.write(XMLHttpRequest.responseText);
document.close();
}
});
Before any ajax request is performed CheckPulse method is invoked (the controller method which can be anything simplest):
[Authorize]
public virtual void CheckPulse() {}
If user is not authenticated (token has expired) such method cannot be accessed (protected by Authorize attribute). Because the framework handles authentication, while token expires, it puts http status 302 to the response. If you don't want your browser to handle 302 response transparently, catch it in Global.asax and change response status - for example to 200 OK. Additionally, add header, which instructs you to process such response in special way (later at the client side):
protected void Application_EndRequest()
{
if (Context.Response.StatusCode == 302
&& (new HttpContextWrapper(Context)).Request.IsAjaxRequest())
{
Context.Response.StatusCode = 200;
Context.Response.AddHeader("REQUIRES_AUTH", "1");
}
}
Finally at the client side check for such custom header. If present - full redirection to logon page should be done (in my case window.location is replaced by url from request which is handled automatically by my framework).
function checkPulse(XMLHttpRequest) {
var location = window.location.href;
$.ajax({
url: "/Controller/CheckPulse",
type: 'GET',
async: false,
beforeSend: null,
success:
function (result, textStatus, xhr) {
if (xhr.getResponseHeader('REQUIRES_AUTH') === '1') {
XMLHttpRequest.abort(); // terminate further ajax execution
window.location = location;
}
}
});
}
I think a better way to handle this is to leverage the existing HTTP protocol response codes, specifically 401 Unauthorized.
Here is how I solved it:
Server side: If session expires, and request is ajax. send a 401 response code header
Client side: Bind to the ajax events
$('body').bind('ajaxSuccess',function(event,request,settings){
if (401 == request.status){
window.location = '/users/login';
}
}).bind('ajaxError',function(event,request,settings){
if (401 == request.status){
window.location = '/users/login';
}
});
IMO this is more generic and you are not writing some new custom spec/header. You also should not have to modify any of your existing ajax calls.
Edit: Per #Rob's comment below, 401 (the HTTP status code for authentication errors) should be the indicator. See 403 Forbidden vs 401 Unauthorized HTTP responses for more detail. With that being said some web frameworks use 403 for both authentication AND authorization errors - so adapt accordingly. Thanks Rob.
I resolved this issue like this:
Add a middleware to process response, if it is a redirect for an ajax request, change the response to a normal response with the redirect url.
class AjaxRedirect(object):
def process_response(self, request, response):
if request.is_ajax():
if type(response) == HttpResponseRedirect:
r = HttpResponse(json.dumps({'redirect': response['Location']}))
return r
return response
Then in ajaxComplete, if the response contains redirect, it must be a redirect, so change the browser's location.
$('body').ajaxComplete(function (e, xhr, settings) {
if (xhr.status == 200) {
var redirect = null;
try {
redirect = $.parseJSON(xhr.responseText).redirect;
if (redirect) {
window.location.href = redirect.replace(/\?.*$/, "?next=" + window.location.pathname);
}
} catch (e) {
return;
}
}
}
Another solution I found (especially useful if you want to set a global behaviour) is to use the $.ajaxsetup() method together with the statusCode property. Like others pointed out, don't use a redirect statuscode (3xx), instead use a 4xx statuscode and handle the redirect client-side.
$.ajaxSetup({
statusCode : {
400 : function () {
window.location = "/";
}
}
});
Replace 400 with the statuscode you want to handle. Like already mentioned 401 Unauthorized could be a good idea. I use the 400 since it's very unspecific and I can use the 401 for more specific cases (like wrong login credentials). So instead of redirecting directly your backend should return a 4xx error-code when the session timed out and you you handle the redirect client-side. Works perfect for me even with frameworks like backbone.js
I have a simple solution that works for me, no server code change needed...just add a tsp of nutmeg...
$(document).ready(function ()
{
$(document).ajaxSend(
function(event,request,settings)
{
var intercepted_success = settings.success;
settings.success = function( a, b, c )
{
if( request.responseText.indexOf( "<html>" ) > -1 )
window.location = window.location;
else
intercepted_success( a, b, c );
};
});
});
I check the presence of html tag, but you can change the indexOf to search for whatever unique string exists in your login page...
Most of the given solutions use a workaround, using an extra header or an inappropiate HTTP code. Those solutions will most probably work but feel a bit 'hacky'. I've come up with another solution.
We're using WIF which is configured to redirect (passiveRedirectEnabled="true") on a 401 response. The redirect is usefull when handling normal requests but won't work for AJAX requests (since browsers won't execute the 302/redirect).
Using the following code in your global.asax you can disable the redirect for AJAX requests:
void WSFederationAuthenticationModule_AuthorizationFailed(object sender, AuthorizationFailedEventArgs e)
{
string requestedWithHeader = HttpContext.Current.Request.Headers["X-Requested-With"];
if (!string.IsNullOrEmpty(requestedWithHeader) && requestedWithHeader.Equals("XMLHttpRequest", StringComparison.OrdinalIgnoreCase))
{
e.RedirectToIdentityProvider = false;
}
}
This allows you to return 401 responses for AJAX requests, which your javascript can then handle by reloading the page. Reloading the page will throw a 401 which will be handled by WIF (and WIF will redirect the user to the login page).
An example javascript to handle 401 errors:
$(document).ajaxError(function (event, jqxhr, settings, exception) {
if (jqxhr.status == 401) { //Forbidden, go to login
//Use a reload, WIF will redirect to Login
location.reload(true);
}
});
This problem may appear then using ASP.NET MVC RedirectToAction method. To prevent form displaying the response in div you can simply do some kind of ajax response filter for incomming responses with $.ajaxSetup. If the response contains MVC redirection you can evaluate this expression on JS side. Example code for JS below:
$.ajaxSetup({
dataFilter: function (data, type) {
if (data && typeof data == "string") {
if (data.indexOf('window.location') > -1) {
eval(data);
}
}
return data;
}
});
If data is: "window.location = '/Acount/Login'" above filter will catch that and evaluate to make the redirection instead of letting the data to be displayed.
Putting together what Vladimir Prudnikov and Thomas Hansen said:
Change your server-side code to detect if it's an XHR. If it is, set the response code of the redirect to 278.
In django:
if request.is_ajax():
response.status_code = 278
This makes the browser treat the response as a success, and hand it to your Javascript.
In your JS, make sure the form submission is via Ajax, check the response code and redirect if needed:
$('#my-form').submit(function(event){
event.preventDefault();
var options = {
url: $(this).attr('action'),
type: 'POST',
complete: function(response, textStatus) {
if (response.status == 278) {
window.location = response.getResponseHeader('Location')
}
else { ... your code here ... }
},
data: $(this).serialize(),
};
$.ajax(options);
});
<script>
function showValues() {
var str = $("form").serialize();
$.post('loginUser.html',
str,
function(responseText, responseStatus, responseXML){
if(responseStatus=="success"){
window.location= "adminIndex.html";
}
});
}
</script>
Let me just quote again the problem as described by #Steg
I had a similar problem to yours. I perform an ajax request that has 2
possible responses: one that redirects the browser to a new page and
one that replaces an existing HTML form on the current page with a new
one.
IMHO this is a real challenge and will have to be officially extended to the current HTTP standards.
I believe the new Http Standard will be to use a new status-code.
meaning: currently 301/302 tells the browser to go and fetch the content of this request to a new location.
In the extended standard, it will say that if the response status: 308 (just an example), then the browser should redirect the main page to the location provided.
That being said; I'm inclined to already mimic this future behavior, and therefore when a document.redirect is needed, I have the server respond as:
status: 204 No Content
x-status: 308 Document Redirect
x-location: /login.html
When JS gets the "status: 204", it checks for the existence of the x-status: 308 header, and does a document.redirect to the page provided in the location header.
Does this make any sense to you?
Try
$(document).ready(function () {
if ($("#site").length > 0) {
window.location = "<%= Url.Content("~") %>" + "Login/LogOn";
}
});
Put it on the login page. If it was loaded in a div on the main page, it will redirect til the login page. "#site" is a id of a div which is located on all pages except login page.
While the answers seem to work for people if you're using Spring Security I have found extending LoginUrlAuthenticationEntryPoint and adding specific code to handle AJAX more robust. Most of the examples intercept all redirects not just authentication failures. This was undesirable for the project I work on. You may find the need to also extend ExceptionTranslationFilter and override the "sendStartAuthentication" method to remove the caching step if you don't want the failed AJAX request cached.
Example AjaxAwareAuthenticationEntryPoint:
public class AjaxAwareAuthenticationEntryPoint extends
LoginUrlAuthenticationEntryPoint {
public AjaxAwareAuthenticationEntryPoint(String loginUrl) {
super(loginUrl);
}
#Override
public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException, ServletException {
if (isAjax(request)) {
response.sendError(HttpStatus.UNAUTHORIZED.value(), "Please re-authenticate yourself");
} else {
super.commence(request, response, authException);
}
}
public static boolean isAjax(HttpServletRequest request) {
return request != null && "XMLHttpRequest".equals(request.getHeader("X-Requested-With"));
}
}
Sources:
1, 2
I solved this by putting the following in my login.php page.
<script type="text/javascript">
if (top.location.href.indexOf('login.php') == -1) {
top.location.href = '/login.php';
}
</script>
Some might find the below useful:
I wanted clients to be redirected to the login page for any rest-action that is sent without an authorization token. Since all of my rest-actions are Ajax based, I needed a good generic way to redirect to the login page instead of handling the Ajax success function.
This is what I've done:
On any Ajax request my server will return a Json 200 response "NEED TO AUTHENTICATE" (if the client needs to authenticate).
Simple example in Java (server side):
#Secured
#Provider
#Priority(Priorities.AUTHENTICATION)
public class AuthenticationFilter implements ContainerRequestFilter {
private final Logger m_logger = LoggerFactory.getLogger(AuthenticationFilter.class);
public static final String COOKIE_NAME = "token_cookie";
#Override
public void filter(ContainerRequestContext context) throws IOException {
// Check if it has a cookie.
try {
Map<String, Cookie> cookies = context.getCookies();
if (!cookies.containsKey(COOKIE_NAME)) {
m_logger.debug("No cookie set - redirect to login page");
throw new AuthenticationException();
}
}
catch (AuthenticationException e) {
context.abortWith(Response.ok("\"NEED TO AUTHENTICATE\"").type("json/application").build());
}
}
}
In my Javascript I've added the following code:
$.ajaxPrefilter(function(options, originalOptions, jqXHR) {
var originalSuccess = options.success;
options.success = function(data) {
if (data == "NEED TO AUTHENTICATE") {
window.location.replace("/login.html");
}
else {
originalSuccess(data);
}
};
});
And that's about it.
in the servlet you should put
response.setStatus(response.SC_MOVED_PERMANENTLY);
to send the '301' xmlHttp status you need for a redirection...
and in the $.ajax function you should not use the .toString() function..., just
if (xmlHttp.status == 301) {
top.location.href = 'xxxx.jsp';
}
the problem is it is not very flexible, you can't decide where you want to redirect..
redirecting through the servlets should be the best way. but i still can not find the right way to do it.
I just wanted to latch on to any ajax requests for the entire page. #SuperG got me started. Here is what I ended up with:
// redirect ajax requests that are redirected, not found (404), or forbidden (403.)
$('body').bind('ajaxComplete', function(event,request,settings){
switch(request.status) {
case 301: case 404: case 403:
window.location.replace("http://mysite.tld/login");
break;
}
});
I wanted to specifically check for certain http status codes to base my decision on. However, you can just bind to ajaxError to get anything other than success (200 only perhaps?) I could have just written:
$('body').bind('ajaxError', function(event,request,settings){
window.location.replace("http://mysite.tld/login");
}
If you also want to pass the values then you can also set the session variables and access
Eg:
In your jsp you can write
<% HttpSession ses = request.getSession(true);
String temp=request.getAttribute("what_you_defined"); %>
And then you can store this temp value in your javascript variable and play around
I didn't have any success with the header solution - they were never picked up in my ajaxSuccess / ajaxComplete method. I used Steg's answer with the custom response, but I modified the JS side some. I setup a method that I call in each function so I can use standard $.get and $.post methods.
function handleAjaxResponse(data, callback) {
//Try to convert and parse object
try {
if (jQuery.type(data) === "string") {
data = jQuery.parseJSON(data);
}
if (data.error) {
if (data.error == 'login') {
window.location.reload();
return;
}
else if (data.error.length > 0) {
alert(data.error);
return;
}
}
}
catch(ex) { }
if (callback) {
callback(data);
}
}
Example of it in use...
function submitAjaxForm(form, url, action) {
//Lock form
form.find('.ajax-submit').hide();
form.find('.loader').show();
$.post(url, form.serialize(), function (d) {
//Unlock form
form.find('.ajax-submit').show();
form.find('.loader').hide();
handleAjaxResponse(d, function (data) {
// ... more code for if auth passes ...
});
});
return false;
}
Finally, I solve the problem by adding a custom HTTP Header. Just before response for every request in server side, i add the current requested url to response's header.
My application type on server is Asp.Net MVC, and it has a good place to do it. in Global.asax i implemented the Application_EndRequest event so:
public class MvcApplication : System.Web.HttpApplication
{
// ...
// ...
protected void Application_EndRequest(object sender, EventArgs e)
{
var app = (HttpApplication)sender;
app.Context.Response.Headers.Add("CurrentUrl",app.Context. Request.CurrentExecutionFilePath);
}
}
It works perfect for me! Now in every response of the JQuery $.post i have the requested url and also other response headers which comes as result of POST method by status 302, 303 ,... .
and other important thing is that there is no need to modify code on server side nor client side.
and the next is the ability to get access to the other information of post action such errors, messages, and ..., In this way.
I posted this, maybe help someone :)
I was having this problem on a django app I'm tinkering with (disclaimer: I'm tinkering to learn, and am in no way an expert). What I wanted to do was use jQuery ajax to send a DELETE request to a resource, delete it on the server side, then send a redirect back to (basically) the homepage. When I sent HttpResponseRedirect('/the-redirect/') from the python script, jQuery's ajax method was receiving 200 instead of 302. So, what I did was to send a response of 300 with:
response = HttpResponse(status='300')
response['Location'] = '/the-redirect/'
return response
Then I sent/handled the request on the client with jQuery.ajax like so:
<button onclick="*the-jquery*">Delete</button>
where *the-jquery* =
$.ajax({
type: 'DELETE',
url: '/resource-url/',
complete: function(jqxhr){
window.location = jqxhr.getResponseHeader('Location');
}
});
Maybe using 300 isn't "right", but at least it worked just like I wanted it to.
PS :this was a huge pain to edit on the mobile version of SO. Stupid ISP put my service cancellation request through right when I was done with my answer!
You can also hook XMLHttpRequest send prototype. This will work for all sends (jQuery/dojo/etc) with one handler.
I wrote this code to handle a 500 page expired error, but it should work just as well to trap a 200 redirect. Ready the wikipedia entry on XMLHttpRequest onreadystatechange about the meaning of readyState.
// Hook XMLHttpRequest
var oldXMLHttpRequestSend = XMLHttpRequest.prototype.send;
XMLHttpRequest.prototype.send = function() {
//console.dir( this );
this.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 500 && this.responseText.indexOf("Expired") != -1) {
try {
document.documentElement.innerHTML = this.responseText;
} catch(error) {
// IE makes document.documentElement read only
document.body.innerHTML = this.responseText;
}
}
};
oldXMLHttpRequestSend.apply(this, arguments);
}
I got a working solulion using the answers from #John and #Arpad link and #RobWinch link
I use Spring Security 3.2.9 and jQuery 1.10.2.
Extend Spring's class to cause 4XX response only from AJAX requests:
public class CustomLoginUrlAuthenticationEntryPoint extends LoginUrlAuthenticationEntryPoint {
public CustomLoginUrlAuthenticationEntryPoint(final String loginFormUrl) {
super(loginFormUrl);
}
// For AJAX requests for user that isn't logged in, need to return 403 status.
// For normal requests, Spring does a (302) redirect to login.jsp which the browser handles normally.
#Override
public void commence(final HttpServletRequest request,
final HttpServletResponse response,
final AuthenticationException authException)
throws IOException, ServletException {
if ("XMLHttpRequest".equals(request.getHeader("X-Requested-With"))) {
response.sendError(HttpServletResponse.SC_FORBIDDEN, "Access Denied");
} else {
super.commence(request, response, authException);
}
}
}
applicationContext-security.xml
<security:http auto-config="false" use-expressions="true" entry-point-ref="customAuthEntryPoint" >
<security:form-login login-page='/login.jsp' default-target-url='/index.jsp'
authentication-failure-url="/login.jsp?error=true"
/>
<security:access-denied-handler error-page="/errorPage.jsp"/>
<security:logout logout-success-url="/login.jsp?logout" />
...
<bean id="customAuthEntryPoint" class="com.myapp.utils.CustomLoginUrlAuthenticationEntryPoint" scope="singleton">
<constructor-arg value="/login.jsp" />
</bean>
...
<bean id="requestCache" class="org.springframework.security.web.savedrequest.HttpSessionRequestCache">
<property name="requestMatcher">
<bean class="org.springframework.security.web.util.matcher.NegatedRequestMatcher">
<constructor-arg>
<bean class="org.springframework.security.web.util.matcher.MediaTypeRequestMatcher">
<constructor-arg>
<bean class="org.springframework.web.accept.HeaderContentNegotiationStrategy"/>
</constructor-arg>
<constructor-arg value="#{T(org.springframework.http.MediaType).APPLICATION_JSON}"/>
<property name="useEquals" value="true"/>
</bean>
</constructor-arg>
</bean>
</property>
</bean>
In my JSPs, add a global AJAX error handler as shown here
$( document ).ajaxError(function( event, jqxhr, settings, thrownError ) {
if ( jqxhr.status === 403 ) {
window.location = "login.jsp";
} else {
if(thrownError != null) {
alert(thrownError);
} else {
alert("error");
}
}
});
Also, remove existing error handlers from AJAX calls in JSP pages:
var str = $("#viewForm").serialize();
$.ajax({
url: "get_mongoDB_doc_versions.do",
type: "post",
data: str,
cache: false,
async: false,
dataType: "json",
success: function(data) { ... },
// error: function (jqXHR, textStatus, errorStr) {
// if(textStatus != null)
// alert(textStatus);
// else if(errorStr != null)
// alert(errorStr);
// else
// alert("error");
// }
});
I hope it helps others.
Update1
I found that I needed to add the option (always-use-default-target="true") to the form-login config.
This was needed since after an AJAX request gets redirected to the login page (due to expired session), Spring remembers the previous AJAX request and auto redirects to it after login. This causes the returned JSON to be displayed on the browser page. Of course, not what I want.
Update2
Instead of using always-use-default-target="true", use #RobWinch example of blocking AJAX requests from the requstCache. This allows normal links to be redirected to their original target after login, but AJAX go to the home page after login.
As alternative to ajax, there is a new Fetch API being developed, which allows manual redirect handling. You need to check if the current browser support is enough for your needs.

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