origin - set header in ajax javascript




Add Header in AJAX Request with jQuery (4)

And that is why you can't create a bot with Javascript, because your options are limited to what the browser allows you to do. You can't just order a browser that follows the CORS policy, which most browsers follow, to send random requests to other origins and allow you to get the response that simply!

Additionally, if you tried to edit some request headers manually like origin-header from the developers tools that come with the browsers, the browser will refuse your edit, and may send a preflight OPTIONS request.

I would like to add a custom header to an AJAX POST request from jQuery.

I have tried this:

$.ajax({
    type: 'POST',
    url: url,
    headers: {
        "My-First-Header":"first value",
        "My-Second-Header":"second value"
    }
    //OR
    //beforeSend: function(xhr) { 
    //  xhr.setRequestHeader("My-First-Header", "first value"); 
    //  xhr.setRequestHeader("My-Second-Header", "second value"); 
    //}
}).done(function(data) { 
    alert(data);
});

When I send this request and I watch with FireBug, I see this header:

OPTIONS xxxx/yyyy HTTP/1.1
Host: 127.0.0.1:6666
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:11.0) Gecko/20100101 Firefox/11.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8
Accept-Language: fr,fr-fr;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive
Origin: null
Access-Control-Request-Method: POST
Access-Control-Request-Headers: my-first-header,my-second-header
Pragma: no-cache
Cache-Control: no-cache

Why do my custom headers go to Access-Control-Request-Headers:

Access-Control-Request-Headers: my-first-header,my-second-header

I was expecting a header values like this:

My-First-Header: first value
My-Second-Header: second value

Is it possible?


Here is an example how to set a Request Header in a JQuery Ajax Call:

$.ajax({
  type: "POST",
  beforeSend: function(request) {
    request.setRequestHeader("Authority", authorizationToken);
  },
  url: "entities",
  data: "json=" + escape(JSON.stringify(createRequestObject)),
  processData: false,
  success: function(msg) {
    $("#results").append("The result =" + StringifyPretty(msg));
  }
});

Try to use rack-cors gem. And add the header field in your ajax call.


What you saw in Firefox was not the actual request; note that the HTTP method is OPTIONS, not POST. It was actually the 'pre-flight' request that the browser makes to determine whether a cross-domain AJAX request should be allowed:

http://www.w3.org/TR/cors/

The Access-Control-Request-Headers header in the pre-flight request includes the list of headers in the actual request. The server is then expected to report back whether these headers are supported in this context or not, before the browser submits the actual request.





http-headers