$http.get is not allowed by Access-Control-Allow-Origin but $.ajax is

Question

I have a problem fetching json from a remote server that I control. I have 2 web applications, one serving data and running on port 3311, the other, requesting data, is running on port 5000.

using jquery the following works:

$.ajax({
  url: "http://localhost:3311/get-data",
  type: 'GET',
  dataType: 'json',
  beforeSend: function(xhr) {
    xhr.setRequestHeader("x-some-header", "some-value");
  }
})
.done(function(data) { 
    $rootScope.$apply(function() {d.resolve(data); });
})
.fail(function(data) {
    $rootScope.$apply(function() {d.reject(data); });
});

when attempting the same get request with angular

$http
    .get("http://localhost:3311/get-data", { headers: {"x-some-header": "some-value"} })
    .success(function(data) { d.resolve(data);})
    .error(function(data) { d.reject(data); });

I receive the error

Origin http://localhost:5000 is not allowed by Access-Control-Allow-Origin.

The console log shows an error occurring after the OPTIONS request returns HTTP200

OPTIONS http://localhost:3311//get-data 200 (OK) angular.min.js:99

(anonymous function) angular.min.js:99

l angular.min.js:95

m angular.min.js:94

(anonymous function) app.js:78

b.extend.each jquery-1.9.1.min.js:3

b.fn.b.each jquery-1.9.1.min.js:3

(anonymous function) app.js:76

d angular.min.js:28

instantiate angular.min.js:28

(anonymous function) angular.min.js:52

updateView angular-ui-states.js:892

e.$broadcast angular.min.js:90

transition angular-ui-states.js:324

h angular.min.js:77

(anonymous function) angular.min.js:78

e.$eval angular.min.js:88

e.$digest angular.min.js:86

e.$apply angular.min.js:88

e angular.min.js:94

o angular.min.js:98

s.onreadystatechange angular.min.js:99

and the headers being returned from the OPTIONS request are

HTTP/1.1 200 OK
Cache-Control: private
Content-Type: text/plain
Server: Microsoft-IIS/8.0
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, OPTIONS
Access-Control-Allow-Headers: Content-Type, Accept, X-Requested-With, x-some-header
X-AspNet-Version: 4.0.30319
X-SourceFiles: =?UTF-8?B?....
X-Powered-By: ASP.NET
Date: Tue, 21 May 2013 01:52:37 GMT
Content-Length: 0

Answer 1

This is probably due to the default behavior of Angular to include the request header 'X-Requested-With', which can cause problems with CORS. This was fixed in v 1.1.1 (the unstable branch - see v1.1.1 bug fixes) by removing the header from cross domain requests: https://github.com/angular/angular.js/issues/1004.

It's easy to remove the header and get this working on the 1.0 branch. The following line will remove the header from all requests (not only CORS) done by the $http service in your app:

yourModule
  .config(function($httpProvider){
    delete $httpProvider.defaults.headers.common['X-Requested-With'];
});

Update A little warning - Angular (like jQuery) doesn't support CORS for IE9. IE10 is the first IE browser that supports CORS. This blogpost describes how you can get CORS support in IE8/IE9 under certain conditions, but it won't work with the Angular $http service: http://blogs.msdn.com/b/ieinternals/archive/2010/05/13/xdomainrequest-restrictions-limitations-and-workarounds.aspx

Answer 2

web.config

<system.webServer> 
<httpProtocol>
     <customHeaders>
       <add name="Access-Control-Allow-Origin" value="*" />
     </customHeaders>
   </httpProtocol>
  </system.webServer>