problem with implementing widget via the_content()

Question

hey guys, I really need you help with this one.

I'm using the subscribe2 Plugin (for email subscriptions). I want to show the signup form as a widget. The plugin author recommends doing it the following way.

$content = apply_filters('the_content', '<!--subscribe2-->');
$content = remove_filter('the_content', 'page_route');
echo $content;

this works fine, except for the fact that I'm additionally using the mingle plugin (kind of a social network plugin).

Whenever I'm on a page of the mingle plugin (like /login, /register, /activity, etc.) the widget with the subscribe form suddenly displays the exact same content as the pages itself? Just weird!

Any idea why that could happen? Or how I could prevent that! I really need a solution for that!

edit: all filters mingle applies...

add_filter('get_avatar', array($this,'override_avatar'), 10, 4);
add_filter('get_comment_author_url', array($this,'override_author_url'));
add_filter('mngl-show-powered-by', array(&$this, 'show_powered_by'));
add_filter('the_content', array( &$this, 'page_route' ), 100);
add_action('wp_enqueue_scripts', array(&$this, 'load_scripts'), 1);
add_action('admin_enqueue_scripts', array(&$this,'load_admin_scripts'));
register_activation_hook(MNGL_PATH."/mingle.php", array( &$this, 'install' ));

// Used to process standalone requests (make sure mingle_init comes before parse_standalone_request)
add_action('init', array(&$this,'mingle_init'));
add_action('init', array(&$this,'parse_standalone_request'));
add_filter('request', array(&$this,'parse_pretty_profile_url'));

add_action('phpmailer_init', array(&$this, 'set_wp_mail_return_path'));
add_action('phpmailer_init', array(&$this, 'set_wp_mailer'));
add_action('admin_init', array(&$this, 'prevent_admin_access'));

add_filter('mngl-activity-types', array( &$this, 'add_activity_types' ));
add_filter('mngl-notification-types', array( &$this, 'add_notification_types' ));

add_filter('mngl-notification-types', array( $this, 'add_notification_types' ));
add_filter('mngl-activity-types', array( &$this, 'add_activity_types' ));
add_action('user_register', array(&$this, 'add_default_friends') );
add_filter('mngl-activity-types', array( &$this, 'add_activity_types' ));

Answer 1

Its extremely difficult to remove a filter that's added as part of an object. You have get the reference to the original object and pass that as part of the function to remove.

Luckily the filter was added at an unusual priority, so you will probably be safe removing all filters at priority 100:

remove_all_filters( 'the_content', 100 );
$content = apply_filters('the_content', '<!--subscribe2-->');
echo $content;

Just make sure that you don't have anything else essential being added at priority 100...

If you have to find only this specific filter to remove, then I'm out of my depth. Anyone else?

Edit:

I had to figure this one out, since I've actually wondered for a while how to remove a filter that was passed by reference. In this case the class MnglAppController which adds the filter is initiated as a variable:

$mngl_app_controller           = new MnglAppController();

So to remove it, you have to globalize that variable, and pass it as part of the remove_filter call:

global $mngl_app_controller;
remove_filter( 'the_content', array($mngl_app_controller, 'page_route'), 100 );
$content = apply_filters('the_content', '<!--subscribe2-->');
echo $content;
add_filter( 'the_content', array($mngl_app_controller, 'page_route'), 100 );

Answer 2

I think you have a little error in your code that will prevent it from working:

$content = apply_filters('the_content', '<!--subscribe2-->');
$content = remove_filter('the_content', 'page_route');
echo $content;

The second line:

$content = remove_filter('the_content', 'page_route');

will put TRUE or FALSE into $content.

Just replace it with

$result_remove_filter = remove_filter('the_content', 'page_route');

and try again.