WordPress: changing the status code on AJAX response

Andrea 18 April 2015 Comments

Use the following code in WordPress for changing the HTTP status code returned from an AJAX call, e.g. setting a 400 – Bad Request error:

function my_ajax() {
  status_header(400);
  echo 'Some return message';
  wp_die();
}
add_action( 'wp_ajax_my_ajax', 'my_ajax' );

Where status_header and wp_die are two WordPress’s functions.

NOTE: be sure to set the status header before any echo statement, otherwise a 200 status code is always returned and you will get this error/warning:

Warning: Cannot modify header information - headers already sent by (output started at /some/path/to/your/php/file.php:232) in /some/path/to/your/php/file.php on line 292

Hint

Set display_errors: Off inside your php.ini file, otherwise if you have a PHP error will be returned a 200 status code and not an error code as you might expect (see here the why).