[FIXED] How to check if the request is an AJAX request with PHP

Issue

I would like to check server-side if a request to my php page is an ajax request or not.

I saw two ways to do this:

First way: sending a GET parameter in the request which tells the page that this is an AJAX request (=mypage.php?ajax)

mypage.php:

if(isset($_GET['ajax'])) {
    //this is an ajax request, process data here.
}

Second way: set a header to the xmlHttpRequest:

client-side js:

xmlHttpRequestObject.open(“GET”,url,true);
xmlHttpRequestObject.setRequestHeader('X-Requested-With', 'XMLHttpRequest');

mypage.php:

if (!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest' ) {
    //request is ajax
}

---

The fact is, those two ways of doing it can easily be hacked, so it's not secure to check if i get an AJAX request like this.

How can i check if i'm receiving an AJAX request?

Solution

There is no sure-fire way of knowing that a request was made via Ajax. You can never trust data coming from the client. You could use a couple of different methods but they can be easily overcome by spoofing.

Answered By - Wayne Whitty

Answer Checked By - David Goodson (PHPFixing Volunteer)