Question

I’m trying to pass an ajax action to /wp-admin/admin-ajax.php, however I can’t seem to get it to call any functions that use a class to encapsulate the namespace. I get the following error:

Warning:  call_user_func_array() expects parameter 1 to be a valid callback, class 'PHP_faq_backend' not found in /wp-includes/plugin.php

My action is as follows:

add_action('wp_ajax_edit_form', array('PHP_faq_backend', 'edit_form'));

Obviously I don’t want to force this by modifying the admin-ajax.php file, but how do I get my classfiles loaded so the action will work?

Answer 1

Make sure you are including your class files somewhere within your WordPress theme (functions.php), or Plugin.

I usually use something like this;

<?php
class Some_Class {

    public function __construct() {
        //logged in users
        add_action('wp_ajax_some_method', array($this,'some_method'));
        //non logged in users
        add_action('wp_ajax_nopriv_some_method', array($this,'some_method'));
    }

    public function some_method(){
        //check nonce values etc
        if ( ! isset( $_REQUEST['some_nonce'] ) || ! wp_verify_nonce( $_REQUEST['some_nonce'], 'class_some_nonce' ) ) {
            wp_die(__('Naughty', 'some-class-textdomain'));
        }

        //proceed with post data validation - then execute method
    }

}

$some_class_instance = new Some_Class();
?>

The above is for registering actions from within a class instance.