406-Not Acceptable Response - jQuery AJAX

Question

I am receiving the 406 error when I am sending a JSON data object through the jQuery AJAX function to a backend service so the data can be stored into the database.

AJAX FUNCTION

data = {
  questions: questions,
  test_id: test_id,
  action: 'update'
};

gmtjax({
    url: gmt.contextPath + 'tests/questions/process_form',
    type: 'POST',
    data: data,
    dataType: 'json',
    $spinner: gmt.$spinnerContainer,
    success: function(returnData) {
      console.log('success');
    },
    error: function(){
      //console.log('error');
    },
    $errorContainer: gmt.$mainContainer
});

JSON structure:

{
    "test_id": "1",
    "action": "update",
    "questions": [
        {
            "question": "Exploitation strategies seek to create value from unfamiliar resources and activities.",
            "options": [
                {
                    "name": "True"
                },
                {
                    "name": "False"
                }
            ]
        }
    ]
} 

Process Form Function (Backend)

function process_form(){
  print_r($_POST);
}

---

When I submit the data the STATUS CODE on the XHR request is 406 Not Acceptable.

Request Header

Accept:application/json, text/javascript, */*; q=0.01
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8,af;q=0.6,ms;q=0.4
Cache-Control:no-cache
Connection:keep-alive
Content-Length:1726
Content-Type:application/x-www-form-urlencoded; charset=UTF-8
Cookie:ci_session=08c62699d06dfcf8ba853cacb350ab3b
Host:testingsite.com
Origin:https://testingsite.com
Pragma:no-cache
Referer:https://testingsite.com/tests/manage/id/194/goto/2
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36
X-Requested-With:XMLHttpRequest

RESPONSE

false

When the request fails it does not even enter the process_form function to print out the POST array.

---

However, when I modify the 'create value' string in the question to something like 'create a value' the form submits successfully. The only thing I can think of is some SQL Injection prevention detection on the server layer (GoDaddy) but I am unsure on how to address this.

What could be causing the 406 error when Content-Type is obviously not the issue.

Answer 1

It could be caused by a module called mod_security and it can cause this problem. Your code looks fine to me. So, check out your host, see if mod_security is installed and enabled, and if it is, try disabling it temporarily and then test this code again. If mod_security is not the culprit, don't forget to re-enable it.