wp_ajax handler with multiple class instances

Question

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:

<?php
class McCustomPost { ... }
$wpMcCustomPost = new McCustomPost();
?>
...
<?php
class McAdmin { ... }
$wpMcAdmin = new McAdmin();
?>

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

<?php
/*
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.

<?php
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);
        exit;  
    }
...
}
$wpMcAdmin = new McAdmin();
?>

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

$('.add-vehicle').click(function(){
        var data = {
            action: "blubb",
            // nonce: ajax_var.nonce,
            id: 1
        };

        $.post(
            ajaxurl,
            data,
            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,

mybecks

Answer 1

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.

Answer 2

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;

        die();
}

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