Cross-Origin Read Blocking (CORB)

Question

I have called third party API using Jquery AJAX. I am getting following error in console:

Cross-Origin Read Blocking (CORB) blocked cross-origin response MY URL with MIME type application/json. See https://www.chromestatus.com/feature/5629709824032768 for more details.

I have used following code for Ajax call :

$.ajax({
  type: 'GET',
  url: My Url,
  contentType: 'application/json',
  dataType:'jsonp',
  responseType:'application/json',
  xhrFields: {
    withCredentials: false
  },
  headers: {
    'Access-Control-Allow-Credentials' : true,
    'Access-Control-Allow-Origin':'*',
    'Access-Control-Allow-Methods':'GET',
    'Access-Control-Allow-Headers':'application/json',
  },
  success: function(data) {
    console.log(data);
  },
  error: function(error) {
    console.log("FAIL....=================");
  }
});

When I checked in Fiddler, I have got the data in response but not in Ajax success method.

Please help me out.

Answer 1

 dataType:'jsonp',

You are making a JSONP request, but the server is responding with JSON.

The browser is refusing to try to treat the JSON as JSONP because it would be a security risk. (If the browser did try to treat the JSON as JSONP then it would, at best, fail).

See this question for more details on what JSONP is. Note that is a nasty hack to work around the Same Origin Policy that was used before CORS was available. CORS is a much cleaner, safer, and more powerful solution to the problem.

---

It looks like you are trying to make a cross-origin request and are throwing everything you can think of at it in one massive pile of conflicting instructions.

You need to understand how the Same Origin policy works.

See this question for an in-depth guide.

---

Now a few notes about your code:

contentType: 'application/json',

• This is ignored when you use JSONP
• You are making a GET request. There is no request body to describe the type of.
• This will make a cross-origin request non-simple, meaning that as well as basic CORS permissions, you also need to deal with a pre-flight.

Remove that.

 dataType:'jsonp',

• The server is not responding with JSONP.

Remove this. (You could make the server respond with JSONP instead, but CORS is better).

responseType:'application/json',

This is not an option supported by jQuery.ajax. Remove this.

xhrFields: { withCredentials: false },

This is the default. Unless you are setting it to true with ajaxSetup, remove this.

  headers: {
    'Access-Control-Allow-Credentials' : true,
    'Access-Control-Allow-Origin':'*',
    'Access-Control-Allow-Methods':'GET',
    'Access-Control-Allow-Headers':'application/json',
  },

• These are response headers. They belong on the response, not the request.
• This will make a cross-origin request non-simple, meaning that as well as basic CORS permissions, you also need to deal with a pre-flight.