Ajax with OOP doesn't work

Question

I have a small script within theme's functions.php file that uses ajax, principle like this:

add_action('admin_head', 'rw_script');
function rw_script() {
    echo '
    <script type="text/javascript">
        // delete image
        $(".delete_image").click(function(){
            var data = $(this).attr("rel");
            $.post(
                ajaxurl,
                {action: \'rw_delete_image\', data: data}, function(response){
                    alert(response); // debug
                }
            );

            return false;
        });
    });
    </script>';
}
function delete_image() {
    if (isset($_POST['attach_id'])) wp_delete_attachment($_POST['attach_id']);
        die();
}
add_action('wp_ajax_rw_delete_image', 'delete_image');

It works fine. But when I turned it into OOP, the ajax doens't work:

class RW_Test {
    function __construct() {
        add_action('admin_head', array(&$this, 'rw_script'));
        add_action('wp_ajax_rw_delete_image', array(&$this, 'delete_image'));
    }
    function rw_script() {
        echo '
        <script type="text/javascript">
            // delete image
            $(".delete_image").click(function(){
                var data = $(this).attr("rel");
                $.post(
                    ajaxurl,
                    {action: \'rw_delete_image\', data: data}, function(response){
                        alert(response); // debug
                    }
                );

                return false;
            });
        });
        </script>';
    }
    function delete_image() {
        if (isset($_POST['attach_id'])) wp_delete_attachment($_POST['attach_id']);
            die();
    }
}

The javascript works fine, i.e when I click on delete links, data is sent properly. But the action for deleting image isn't fired.

Do you know how to solve this? Please help me. Thank you.

Answer 1

You need to create a new instance of the class so that your constructor is called and your actions are registered. e.g. you need to add something like $test = new PR_Test; below the definition of PR_Test.

Answer 2

It should work; I've done the exact same thing successfully in a couple different styles of custom post type classes. There's a possibility that your original RW_Test object is being overwritten—perhaps you're using the same variable name somewhere else?

At any rate, a good place to start troubleshooting is to look at all the active hooks to make sure that your "wp_ajax_rw_delete_image" action is active (and paired with the correct RW_Test object) when you initiate the AJAX call. I suggest this hooks debugger from Rarst to echo the active hooks in your admin page.

Answer 3

It's been a long time since this question, now my code has changed a lot. But after re-look at the code, and I think the request should be:

$.post(
    ajaxurl,
    {action: 'rw_delete_image', attach_id: data}, function(response){
         alert(response); // debug
    }
);

not {action: 'rw_delete_image', data: data}.