I apologize if this question has already been answered.
I am trying to retrieve data from a REST web service that exposes a JSON interface using jQuery .ajax call.
When I call the service using the URL, the jQuery call fails although I get a HTTP status code 200 OK.
When I copy the response into a file on the filesystem and retrieve this, the same call works.
Both the file I am accessing and the web service I am calling are on the same machine.
Some notes on the url used in the code below:
Using:
url: "http://localhost:9090/app/user/861",
the call fails, goes into .fail on all browsers.
The URL itself returns the json on all browsers:
{
"userid": 861,
"employeeno": "123",
"jobdesc": "Developer",
"firstname": "Jasper",
"lastname": "Fitussi"
}
when using "test.json" in the local filesystem following is the behavior:
url: "ajax/test.json",
On Firefox, the call executes, goes into .done and displays the result on page.
On Chrome, the call fails with status 404 and the following message -
"No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access."
I tried different combinations changing dataType:"jsonp", adding a ?callback=? to the end of the URL, and enclosing the data in the test.json with a '(' and a ')' without luck.
Please understand I am new to UI programming, javascript and jQuery.
Please help with what I am doing wrong. Here's the javascript:
<script src="http://code.jquery.com/jquery-1.10.2.js" type="text/javascript">
</script>
<script type="text/javascript">
$(document).ready(function () {
$.ajax({
type: "GET",
url:"ajax/test.json",
// the following commented call fails, goes into .fail
// url:"http://localhost:9090/app/user/861",
contentType: "application/json",
accepts: "application/json",
dataType: "json"
})
.done(function(data) {
alert("Success");
console.log(data);
var items = [];
$.each( data, function( key, val ) {
items.push( "<li id='" + key + "'>" + val + "</li>");
});
$( "<ul/>", {
"class": "my-new-list",
html: items.join( "" )
}).appendTo( "body" );
})
.fail(function(data) {
console.log(data);
alert("Failed");
})
.always(function() {
alert("In Always");
});
});
</script>
The following is the output when I paste the url into the browser (also the contents of ajax/test.json):
{
"userid": 861,
"employeeno": "123",
"jobdesc": "Developer",
"firstname": "Jasper",
"lastname": "Fitussi"
}
Your problem is not about UI programming, it's about the security model of modern browsers :p
Access-Control-Allow-Origin errors occurs when you call a webservice (ie: load a JSON file) from a domain that is different from the one hosting your HTML page.
In your case, you are opening the html file from your hard drive (file:///) and calling a webservice on localhost.
This is a security feature in all modern browsers that forbid getting data from a foreign webservice without the webservice owners authorizing you (or everyone, wildcards are allowed) to call it.
I recommend reading the following guide from MDN, so that you understand WHY you are having this problem.
It will then be easy to resolve
https://developer.mozilla.org/en/docs/HTTP/Access_control_CORS
If you control the source code of the webservice, or the webserver hosting it, you need to add Access-Control-Allow-Origin HTTP headers.
Do you make your ajax call using Apache on wamp, lamp, xampp or mamp or not? I think you work directly using some files lets say on your desktop and not from the www file of wamp. If the browser sends a correct url then the backend responds great, your frontend code seems fine so i think chrome complains about your not using localhost. Am i right? Whats your local development setup?
If it's a local file on the client-side, use file:/// to prefix the URL:
url: 'file:///ajax/test.json'
The third / in file:/// indicates:
As a special case, can be the string "localhost" or the empty
string; this is interpreted as `the machine from which the URL is
being interpreted'.
3.10
Reference here
Download a tool called fiddler, from http://fiddler2.com/ great way to debug web requests and to see why they are failing.
This will help you narrow down the issue you are experiencing and we can help you further because currently its all guess work.
I had the same issue, all worked fine in I.E and FireFox, a had one ajax call to a rest service using jsonp and it worked fine in chrome, however when I tried to load a file using jsonp I got the cross domain error. In short i had to add "file:" to my file path in the url
$.ajax({
type : 'GET',
url : 'file:jsondata/rain_acc_data.json',
dataType : 'jsonp',
jsonpCallback : "jsoncallback",
success : function(data) {
aler('ok');
},
error : function(jqXHR, status) {
alert("Failed to load list" + status + jqXHR);
}
});
this worked for me, make sure to wrap your json in the file with jsoncallback("your jason here");
I am facing this strange error in using $.post.
works
$("#add-video").click(function(){
var url = $("#new-video-url").val();
$('#loader').show();
$.post( base_url + "forms/coach/get_url.php", { url:url, base_url:base_url }, function(data){
alert(data);
$('#loader').hide();
});
});
The above piece of code, shows me the json array I am receiving using a php file, and also shows the title field here, and hides the loader image.
But when I alert(data.title), it shows me undefined. More over, when I add datatype 'json' to $.post,
doesn't work
$("#add-video").click(function(){
var url = $("#new-video-url").val();
$('#loader').show();
$.post( base_url + "forms/coach/get_url.php", { url:url, base_url:base_url }, function(data){
alert(data);
$('#loader').hide();
}, "json"); //Added datatype here.
});
This neither alerts anything nor does it hide the loader image. I also tried,
$("#add-video").click(function(){
var url = $("#new-video-url").val();
$('#loader').show();
$.post( base_url + "forms/coach/get_url.php", { url:url, base_url:base_url }, function(data){
jQuery.parseJSON(data);
alert(data.title);
$('#loader').hide();
});
});
The above one too neither alerts anything nor does it hide the loader. And then I tried this one too that did nothing.
$("#add-video").click(function(){
var url = $("#new-video-url").val();
$('#loader').show();
$.post( base_url + "forms/coach/get_url.php", { url:url, base_url:base_url }, function(data){
jQuery.parseJSON(data); //tried without this too.
alert(data['title']);
$('#loader').hide();
});
});
The strangest thing is that I have previously used json as I have shown in the 2nd script(out of 4), and that works normally. My JS console too doesn't show any errors or warning. What am I doing wrong here? How do I access the title field of data?
If this helps, here is how I send the json array,
$json = array("title" => $title, "embed" => $embed, "desc" => $desc, "duration" => $duration, "date" => $date);
print_r(json_encode($json));
I would really appreciate if someone can point out the error and tell me why my scripts are failing, similar functions worked in other js file.
here is my data, that is returned by server,
{"title":"Sunn Raha Hai Na Tu Aashiqui 2 Full Song With Lyrics |
Aditya Roy Kapur, Shraddha Kapoor","embed":"\r\t\t\t\t\t\r\t\t\t\t\t</param></param>\r\t\t\t\t\t</param>\r\t\t\t\t\t\r\t\t\t\t\t</embed></object>","desc":"Presenting
full song \"Sun Raha Hai Na Tu\" with lyrics from movie \"Aashiqui 2\"
produced by T-Series Films & Vishesh Films, starring Aditya Roy Kapur,
Shraddha Kapoor in voice of Ankit Tiwari. \n\nSong: SUNN RAHA
HAI\nSinger: ANKIT TIWARI\nMusic Director: ANKIT TIWARI\nAssistant Mix
Engineer - MICHAEL EDWIN PILLAI\nMixed and Mastered by ERIC PILLAI
(FUTURE SOUND OF BOMBAY)\nLyrics:SANDEEP NATH\nMovie: AASHIQUI
2\nProducer: BHUSHAN KUMAR KRISHAN KUAMR Producer: MUKESH BHATT
\nDirector: MOHIT SURI\nMusic Label: T-SERIES\n\nBuy from iTunes -
https://itunes.apple.com/in/album/aashiqui-2-original-motion/id630590910?ls=1\n\nEnjoy
& stay connected with us!! \n\nSUBSCRIBE T-Series channel for
unlimited entertainment\nhttp://www.youtube.com/tseries\n\nCircle
us on G+ \nhttp://www.google.com/+tseriesmusic\n\nLike us on
Facebook\nhttp://www.facebook.com/tseriesmusic\n\nFollow
us\nhttp://www.twitter.com/_Tseries","duration":"391","date":"2013-04-03"}
Edit
This worked suddenly.. :o
$("#add-video").click(function(){
var url = $("#new-video-url").val();
$('#loader').show();
$.post( base_url + "forms/coach/get_url.php", { url:url, base_url:base_url }, function(data){
alert(data.desc);
console.log(data.desc);
$("#loader").hide();
}, "json");
});
In comments, you mention that this AJAX corresponds to a YouTube API.
YouTube's blog announced in 2012 that they would support CORS, which uses server-side header flags that compatible browsers interpret as permitting requests that would otherwise be prohibited by browser security Same-Origin-Policy.
Assuming, as you say, the first example worked, the first issue was "Why did (a subsequent) alert(data.title) fail? (my edit) ". If you type alert(data.title) in the console, it will fail because the scope of data is the callback function where it is defined as a parameter, and in the global scope data is undefined. If you try to pass data back to the global scope somehow, it can still be undefined because $.post returns immediately, before the data has been fetched, and merely queues a request and sets the callback function you supply to handle the reply.
The second example, which explicitly sets the $.post dataType parameter to 'json', may fail with CORS based API because the mime types for json are not allowed to be sent up to the server as Content-Type: for a simple CORS request, and $.post will as far as I know only do simple requests without preflight. $.ajax can possibly do the more complex requests if correctly applied.
The work around to keep using $.post is not to use json as the expected data type, send requests up as form data, the server may send you back json anyway if that is what the API says will happen, which can be verified while testing the code.
From https://developer.mozilla.org/en-US/docs/HTTP/Access_control_CORS
Simple requests
A simple cross-site request is one that:
Only uses GET, HEAD or POST.
If POST is used to send data to the
server, the Content-Type of the data sent to the server with the HTTP
POST request is one of application/x-www-form-urlencoded,
multipart/form-data, or text/plain.
Notice that application/json did not make the list of what Content-Type is permissible in a simple CORS request.
See also A CORS POST request works from plain javascript, but why not with jQuery?
Use ajax as
$.ajax({
url:url,
type:'post',
dataType:'json',
success:callback
})
With this type you can set lots of parameter in low level.
With datatype attribute jQuery parses JSON and send data as callback function.
I think you have to replace all single \ with double '\' to feed it to JSON.parse.
How do I send a cross-domain POST request via JavaScript?
Notes - it shouldn't refresh the page, and I need to grab and parse the response afterwards.
Update: Before continuing everyone should read and understand the web.dev tutorial on CORS. It is easy to understand and very clear.
If you control the server being POSTed, simply leverage the "Cross-Origin Resource Sharing standard" by setting response headers on the server. This answer is discussed in other answers in this thread, but not very clearly in my opinion.
In short here is how you accomplish the cross domain POST from from.com/1.html to to.com/postHere.php (using PHP as an example). Note: you only need to set Access-Control-Allow-Origin for NON OPTIONS requests - this example always sets all headers for a smaller code snippet.
In postHere.php setup the following:
switch ($_SERVER['HTTP_ORIGIN']) {
case 'http://from.com': case 'https://from.com':
header('Access-Control-Allow-Origin: '.$_SERVER['HTTP_ORIGIN']);
header('Access-Control-Allow-Methods: GET, PUT, POST, DELETE, OPTIONS');
header('Access-Control-Max-Age: 1000');
header('Access-Control-Allow-Headers: Content-Type, Authorization, X-Requested-With');
break;
}
This allows your script to make cross domain POST, GET and OPTIONS. This will become clear as you continue to read...
Setup your cross domain POST from JS (jQuery example):
$.ajax({
type: 'POST',
url: 'https://to.com/postHere.php',
crossDomain: true,
data: '{"some":"json"}',
dataType: 'json',
success: function(responseData, textStatus, jqXHR) {
var value = responseData.someKey;
},
error: function (responseData, textStatus, errorThrown) {
alert('POST failed.');
}
});
When you do the POST in step 2, your browser will send a "OPTIONS" method to the server. This is a "sniff" by the browser to see if the server is cool with you POSTing to it. The server responds with an "Access-Control-Allow-Origin" telling the browser its OK to POST|GET|ORIGIN if request originated from "http://from.com" or "https://from.com". Since the server is OK with it, the browser will make a 2nd request (this time a POST). It is good practice to have your client set the content type it is sending - so you'll need to allow that as well.
MDN has a great write-up about HTTP access control, that goes into detail of how the entire flow works. According to their docs, it should "work in browsers that support cross-site XMLHttpRequest". This is a bit misleading however, as I THINK only modern browsers allow cross domain POST. I have only verified this works with safari,chrome,FF 3.6.
Keep in mind the following if you do this:
Your server will have to handle 2 requests per operation
You will have to think about the security implications. Be careful before doing something like 'Access-Control-Allow-Origin: *'
This wont work on mobile browsers. In my experience they do not allow cross domain POST at all. I've tested android, iPad, iPhone
There is a pretty big bug in FF < 3.6 where if the server returns a non 400 response code AND there is a response body (validation errors for example), FF 3.6 wont get the response body. This is a huge pain in the ass, since you cant use good REST practices. See bug here (its filed under jQuery, but my guess is its a FF bug - seems to be fixed in FF4).
Always return the headers above, not just on OPTION requests. FF needs it in the response from the POST.
If you control the remote server, you should probably use CORS, as described in this answer; it's supported in IE8 and up, and all recent versions of FF, GC, and Safari. (But in IE8 and 9, CORS won't allow you to send cookies in the request.)
So, if you don't control the remote server, or if you have to support IE7, or if you need cookies and you have to support IE8/9, you'll probably want to use an iframe technique.
Create an iframe with a unique name. (iframes use a global namespace for the entire browser, so pick a name that no other website will use.)
Construct a form with hidden inputs, targeting the iframe.
Submit the form.
Here's sample code; I tested it on IE6, IE7, IE8, IE9, FF4, GC11, S5.
function crossDomainPost() {
// Add the iframe with a unique name
var iframe = document.createElement("iframe");
var uniqueString = "CHANGE_THIS_TO_SOME_UNIQUE_STRING";
document.body.appendChild(iframe);
iframe.style.display = "none";
iframe.contentWindow.name = uniqueString;
// construct a form with hidden inputs, targeting the iframe
var form = document.createElement("form");
form.target = uniqueString;
form.action = "http://INSERT_YOUR_URL_HERE";
form.method = "POST";
// repeat for each parameter
var input = document.createElement("input");
input.type = "hidden";
input.name = "INSERT_YOUR_PARAMETER_NAME_HERE";
input.value = "INSERT_YOUR_PARAMETER_VALUE_HERE";
form.appendChild(input);
document.body.appendChild(form);
form.submit();
}
Beware! You won't be able to directly read the response of the POST, since the iframe exists on a separate domain. Frames aren't allowed to communicate with each other from different domains; this is the same-origin policy.
If you control the remote server but you can't use CORS (e.g. because you're on IE8/IE9 and you need to use cookies), there are ways to work around the same-origin policy, for example by using window.postMessage and/or one of a number of libraries allowing you to send cross-domain cross-frame messages in older browsers:
Porthole
XSSInterface
EasyXDM
jQuery PostMessage Plugin
If you don't control the remote server, then you can't read the response of the POST, period. It would cause security problems otherwise.
Create an iFrame,
put a form in it with Hidden inputs,
set the form's action to the URL,
Add iframe to document
submit the form
Pseudocode
var ifr = document.createElement('iframe');
var frm = document.createElement('form');
frm.setAttribute("action", "yoururl");
frm.setAttribute("method", "post");
// create hidden inputs, add them
// not shown, but similar (create, setAttribute, appendChild)
ifr.appendChild(frm);
document.body.appendChild(ifr);
frm.submit();
You probably want to style the iframe, to be hidden and absolutely positioned. Not sure cross site posting will be allowed by the browser, but if so, this is how to do it.
Keep it simple:
cross-domain POST:
use crossDomain: true,
shouldn't refresh the page:
No, it will not refresh the page as the success or error async callback will be called when the server send back the response.
Example script:
$.ajax({
type: "POST",
url: "http://www.yoururl.com/",
crossDomain: true,
data: 'param1=value1¶m2=value2',
success: function (data) {
// do something with server response data
},
error: function (err) {
// handle your error logic here
}
});
If you have access to all servers involved, put the following in the header of the reply for the page being requested in the other domain:
PHP:
header('Access-Control-Allow-Origin: *');
For example, in Drupal's xmlrpc.php code you would do this:
function xmlrpc_server_output($xml) {
$xml = '<?xml version="1.0"?>'."\n". $xml;
header('Connection: close');
header('Content-Length: '. strlen($xml));
header('Access-Control-Allow-Origin: *');
header('Content-Type: application/x-www-form-urlencoded');
header('Date: '. date('r'));
// $xml = str_replace("\n", " ", $xml);
echo $xml;
exit;
}
This probably creates a security problem, and you should make sure that you take the appropriate measures to verify the request.
Check the post_method function in http://taiyolab.com/mbtweet/scripts/twitterapi_call.js - a good example for the iframe method described above.
Create two hidden iframes (add "display: none;" to the css style). Make your second iframe point to something on your own domain.
Create a hidden form, set its method to "post" with target = your first iframe, and optionally set enctype to "multipart/form-data" (I'm thinking you want to do POST because you want to send multipart data like pictures?)
When ready, make the form submit() the POST.
If you can get the other domain to return javascript that will do Cross-Domain Communication With Iframes (http://softwareas.com/cross-domain-communication-with-iframes) then you are in luck, and you can capture the response as well.
Of course, if you want to use your server as a proxy, you can avoid all this. Simply submit the form to your own server, which will proxy the request to the other server (assuming the other server isn't set up to notice IP discrepancies), get the response, and return whatever you like.
One more important thing to note!!!
In example above it's described how to use
$.ajax({
type : 'POST',
dataType : 'json',
url : 'another-remote-server',
...
});
JQuery 1.6 and lower has a bug with cross-domain XHR.
According to Firebug no requests except OPTIONS were sent. No POST. At all.
Spent 5 hours testing/tuning my code. Adding a lot of headers on the remote server (script). Without any effect.
But later, I've updated JQuery lib to 1.6.4, and everything works like a charm.
If you want to do this in ASP.net MVC environment with JQuery AJAX, follow these steps:
(this is a summary of the solution offered at this thread)
Assume that "caller.com"(can be any website) needs to post to "server.com"(an ASP.net MVC application)
On the "server.com" app's Web.config add the following section:
<httpProtocol>
<customHeaders>
<add name="Access-Control-Allow-Origin" value="*" />
<add name="Access-Control-Allow-Headers" value="Content-Type" />
<add name="Access-Control-Allow-Methods" value="POST, GET, OPTIONS" />
</customHeaders>
</httpProtocol>
On the "server.com", we'll have the following action on the controller(called "Home") to which we will be posting:
[HttpPost]
public JsonResult Save()
{
//Handle the post data...
return Json(
new
{
IsSuccess = true
});
}
Then from the "caller.com", post data from a form(with the html id "formId") to "server.com" as follow:
$.ajax({
type: "POST",
url: "http://www.server.com/home/save",
dataType: 'json',
crossDomain: true,
data: $(formId).serialize(),
success: function (jsonResult) {
//do what ever with the reply
},
error: function (jqXHR, textStatus) {
//handle error
}
});
There is one more way (using html5 feature). You can use proxy iframe hosted on that other domain, you send message using postMessage to that iframe, then that iframe can do POST request (on same domain) and postMessage back with reposnse to the parent window.
parent on sender.com
var win = $('iframe')[0].contentWindow
function get(event) {
if (event.origin === "http://reciver.com") {
// event.data is response from POST
}
}
if (window.addEventListener){
addEventListener("message", get, false)
} else {
attachEvent("onmessage", get)
}
win.postMessage(JSON.stringify({url: "URL", data: {}}),"http://reciver.com");
iframe on reciver.com
function listener(event) {
if (event.origin === "http://sender.com") {
var data = JSON.parse(event.data);
$.post(data.url, data.data, function(reponse) {
window.parent.postMessage(reponse, "*");
});
}
}
// don't know if we can use jQuery here
if (window.addEventListener){
addEventListener("message", listener, false)
} else {
attachEvent("onmessage", listener)
}
High level.... You need to have a cname setup on your server so that other-serve.your-server.com points to other-server.com.
Your page dynamically creates an invisible iframe, which acts as your transport to other-server.com. You then have to communicate via JS from your page to the other-server.com and have call backs that return the data back to your page.
Possible but requires coordination from your-server.com and other-server.com
I think the best way is to use XMLHttpRequest (e.g. $.ajax(), $.post() in jQuery) with one of Cross-Origin Resource Sharing polyfills https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-Browser-Polyfills#wiki-CORS
This is an old question, but some new technology might help someone out.
If you have administrative access to the other server then you can use the opensource Forge project to accomplish your cross-domain POST. Forge provides a cross-domain JavaScript XmlHttpRequest wrapper that takes advantage of Flash's raw socket API. The POST can even be done over TLS.
The reason you need administrative access to the server you are POSTing to is because you must provide a cross-domain policy that permits access from your domain.
http://github.com/digitalbazaar/forge
I know this is an old question, but I wanted to share my approach. I use cURL as a proxy, very easy and consistent. Create a php page called submit.php, and add the following code:
<?
function post($url, $data) {
$header = array("User-Agent: " . $_SERVER["HTTP_USER_AGENT"], "Content-Type: application/x-www-form-urlencoded");
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_HTTPHEADER, $header);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
$response = curl_exec($curl);
curl_close($curl);
return $response;
}
$url = "your cross domain request here";
$data = $_SERVER["QUERY_STRING"];
echo(post($url, $data));
Then, in your js (jQuery here):
$.ajax({
type: 'POST',
url: 'submit.php',
crossDomain: true,
data: '{"some":"json"}',
dataType: 'json',
success: function(responseData, textStatus, jqXHR) {
var value = responseData.someKey;
},
error: function (responseData, textStatus, errorThrown) {
alert('POST failed.');
}
});
Should be possible with a YQL custom table + JS XHR, take a look at:
http://developer.yahoo.com/yql/guide/index.html
I use it to do some client side (js) html scraping, works fine
(I have a full audio player, with search on internet/playlists/lyrics/last fm informations, all client js + YQL)
CORS is for you.
CORS is "Cross Origin Resource Sharing", is a way to send cross domain request.Now the XMLHttpRequest2 and Fetch API both support CORS, and it can send both POST and GET request
But it has its limits.Server need to specific claim the Access-Control-Allow-Origin, and it can not be set to '*'.
And if you want any origin can send request to you, you need JSONP (also need to set Access-Control-Allow-Origin, but can be '*')
For lots of request way if you don't know how to choice, I think you need a full functional component to do that.Let me introduce a simple component https://github.com/Joker-Jelly/catta
If you are using modern browser (> IE9, Chrome, FF, Edge, etc.), Very Recommend you to use a simple but beauty component https://github.com/Joker-Jelly/catta.It have no dependence, Less than 3KB, and it support Fetch, AJAX and JSONP with same deadly sample syntax and options.
catta('./data/simple.json').then(function (res) {
console.log(res);
});
It also it support all the way to import to your project, like ES6 module, CommonJS and even <script> in HTML.
If you have access to the cross domain server and don't want to make any code changes on server side, you can use a library called - 'xdomain'.
How it works:
Step 1:
server 1: include the xdomain library and configure the cross domain as a slave:
<script src="js/xdomain.min.js" slave="https://crossdomain_server/proxy.html"></script>
Step 2:
on cross domain server, create a proxy.html file and include server 1 as a master:
proxy.html:
<!DOCTYPE HTML>
<script src="js/xdomain.min.js"></script>
<script>
xdomain.masters({
"https://server1" : '*'
});
</script>
Step 3:
Now, you can make an AJAX call to the proxy.html as endpoint from server1. This is bypass the CORS request. The library internally uses iframe solution which works with Credentials and all possible methods: GET, POST etc.
Query ajax code:
$.ajax({
url: 'https://crossdomain_server/proxy.html',
type: "POST",
data: JSON.stringify(_data),
dataType: "json",
contentType: "application/json; charset=utf-8"
})
.done(_success)
.fail(_failed)