Corey Ogburn Corey Ogburn - 1 month ago 30
Ajax Question

AJAX in Chrome sending OPTIONS instead of GET/POST/PUT/DELETE?

I am working on an internal web application at work. In IE10 the requests work fine, but in Chrome all the AJAX requests (which there are many) are sent using OPTIONS instead of whatever defined method I give it. Technically my requests are "cross domain." The site is served on localhost:6120 and the service I'm making AJAX requests to is on 57124. This closed jquery bug defines the issue, but not a real fix.

What can I do to use the proper http method in ajax requests?

Edit:

This is in the document load of every page:

jQuery.support.cors = true;


And every AJAX is built similarly:

var url = 'http://localhost:57124/My/Rest/Call';
$.ajax({
url: url,
dataType: "json",
data: json,
async: true,
cache: false,
timeout: 30000,
headers: { "x-li-format": "json", "X-UserName": userName },
success: function (data) {
// my success stuff
},
error: function (request, status, error) {
// my error stuff
},
type: "POST"
});

Answer

Chrome is preflighting the request to look for CORS headers. If the request is acceptable, it will then send the real request. If you're doing this cross-domain, you will simply have to deal with it or else find a way to make the request non-cross-domain. This is why the jQuery bug was closed as won't-fix. This is by design.

Unlike simple requests (discussed above), "preflighted" requests first send an HTTP request by the OPTIONS method to the resource on the other domain, in order to determine whether the actual request is safe to send. Cross-site requests are preflighted like this since they may have implications to user data. In particular, a request is preflighted if:

  • It uses methods other than GET, HEAD or POST. Also, if POST is used to send request data with a Content-Type other than application/x-www-form-urlencoded, multipart/form-data, or text/plain, e.g. if the POST request sends an XML payload to the server using application/xml or text/xml, then the request is preflighted.
  • It sets custom headers in the request (e.g. the request uses a header such as X-PINGOTHER)