Eight months ago I asked nearly the same question over there. But the Problem is still not solved so far.

But I have an additional ideaa why it is failing. In the meantime my code advanced. I have multiple classes which all have the same structure:

class McCustomPost { ... }
$wpMcCustomPost = new McCustomPost();
class McAdmin { ... }
$wpMcAdmin = new McAdmin();

and then I have my "starter" file which requires all files and has the plugin header:

Plugin Name: MC 2.0
Plugin URI: ...
Description: ...
Version: 0.0.75
Author: ...
Author URI: ...
License: GPL2

define( 'MC_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );

require_once( MC_PLUGIN_DIR . 'class.mc.php'               );
require_once( MC_PLUGIN_DIR . 'class.mc-admin.php'          );
require_once( MC_PLUGIN_DIR . 'class.mc-custom-post.php' );

register_activation_hook( __FILE__, array( 'Mc', 'plugin_activation' ) );
register_deactivation_hook( __FILE__, array( 'Mc', 'plugin_deactivation' ) );

$wpMc = new Mc();

During the require_once the admin and custom post classes getting properly instantiated. But when I fire an ajax request from the admin class the request is newer returned. It reaches the JS file but after that the callback is not called, I guess it's not found.

class McAdmin {
    protected $pluginPath;
    private $dbHandler;  

    public function __construct()  {
        $this->pluginPath = dirname(__FILE__);

        add_action( 'admin_enqueue_scripts', array( $this,'add_admin_scripts') ); 
        add_action( 'wp_ajax_blubb', array( $this, 'add_vehicle' ) );  

    public function add_admin_scripts( ){
        wp_enqueue_script( 'admin_scripts', plugins_url( 'js/functions.admin.js', __FILE__ ),   array('jquery') );

        // wp_localize_script('admin_scripts', 'ajax_var', array(  
        // 'nonce' => wp_create_nonce( 'ajax-nonce' )  
        // ) );

    public function add_vehicle()  
        // $nonce = $_POST['nonce'];  

        // if ( ! wp_verify_nonce( $nonce, 'ajax-nonce' ) )  
        //     die ( 'Busted!');

        $title = $_POST['id'];
        wp_die("Post Id: " . $title);
$wpMcAdmin = new McAdmin();

My JS file - the success callback is not executed...

        var data = {
            action: "blubb",
            // nonce: ajax_var.nonce,
            id: 1

            function( response ) { //on success
                alert('Server response from the AJAX URL ' + response);

I assume, that during the institution of McAdmin() class inside Mc() the callback don't know where to go back. How can I get my callback in the correct class instance (McAdmin())?

Thanks & BR,



Your McAdmin seems fine - the problem is likely one of two reasons:

  1. Another AJAX hook for blubb is terminating the script before McAdmin::get_vehicle
  2. You need to add the same hook for wp_ajax_nopriv_blubb - for non-logged in AJAX requests (otherwise it fails silently).

If neither is the cause, you need to do a little HTTP inspecting - I use Firebug or HttpFox - and debug the server response for the AJAX request.

  • tried your hints and the http inspecting drove me insane. The data always gets properly transfered. I often got the result of 0 that the callback function could not be found. At the end it was as I described it in my answer below this post. Nevertheless thank you for your help – mybecks Aug 28 '14 at 12:16

I finally solved it, my problem was that I forget to send back the results to JS file. I did it now with:

public function add_vehicle()
        $response = json_encode( $POST ); //as sample

        // response output -> sent back to javascript file
        header( "Content-Type: application/json" );
        echo $response;


Also I have forgotten the die(); at the end of the function.

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