{"id":25961,"date":"2022-12-14T16:48:43","date_gmt":"2022-12-14T11:18:43","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-how-to-remove-a-filter-that-is-an-object-method\/"},"modified":"2022-12-14T16:48:43","modified_gmt":"2022-12-14T11:18:43","slug":"solved-how-to-remove-a-filter-that-is-an-object-method","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-how-to-remove-a-filter-that-is-an-object-method\/","title":{"rendered":"[Solved] How to remove a filter that is an object method?"},"content":{"rendered":"

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That\u2019s a very good question. It goes down to the dark heart of the plugin API and best programming practices.<\/p>\n

For the following answer I created a simple plugin to illustrate the problem with easy to read code.<\/p>\n

<?php # -*- coding: utf-8 -*-\n\/* Plugin Name: Anonymous OOP Action *\/\n\nif ( ! class_exists( 'Anonymous_Object' ) )\n{\n    \/**\n     * Add some actions with randomized global identifiers.\n     *\/\n    class Anonymous_Object\n    {\n        public function __construct()\n        {\n            add_action( 'wp_footer', array ( $this, 'print_message_1' ), 5 );\n            add_action( 'wp_footer', array ( $this, 'print_message_2' ), 5 );\n            add_action( 'wp_footer', array ( $this, 'print_message_3' ), 12 );\n        }\n\n        public function print_message_1()\n        {\n            print '<p>Kill me!<\/p>';\n        }\n\n        public function print_message_2()\n        {\n            print '<p>Me too!<\/p>';\n        }\n\n        public function print_message_3()\n        {\n            print '<p>Aaaand me!<\/p>';\n        }\n    }\n\n    \/\/ Good luck finding me!\n    new Anonymous_Object;\n}\n<\/code><\/pre>\n
Now we see this:<\/p>\n
\"enter<\/p>\n
WordPress needs a name<\/strong> for the filter. We didn\u2019t provide one, so WordPress calls _wp_filter_build_unique_id()<\/code><\/a> and creates one. This name is not predictable because it uses spl_object_hash()<\/code><\/a>.<\/p>\n
If we run a var_export()<\/code><\/a> on $GLOBALS['wp_filter'][ 'wp_footer' ]<\/code> we get something like this now:<\/p>\n
array (\n  5 => \n  array (\n    '000000002296220e0000000013735e2bprint_message_1' => \n    array (\n      'function' => \n      array (\n        0 => \n        Anonymous_Object::__set_state(array(\n        )),\n        1 => 'print_message_1',\n      ),\n      'accepted_args' => 1,\n    ),\n    '000000002296220e0000000013735e2bprint_message_2' => \n    array (\n      'function' => \n      array (\n        0 => \n        Anonymous_Object::__set_state(array(\n        )),\n        1 => 'print_message_2',\n      ),\n      'accepted_args' => 1,\n    ),\n  ),\n  12 => \n  array (\n    '000000002296220e0000000013735e2bprint_message_3' => \n    array (\n      'function' => \n      array (\n        0 => \n        Anonymous_Object::__set_state(array(\n        )),\n        1 => 'print_message_3',\n      ),\n      'accepted_args' => 1,\n    ),\n  ),\n  20 => \n  array (\n    'wp_print_footer_scripts' => \n    array (\n      'function' => 'wp_print_footer_scripts',\n      'accepted_args' => 1,\n    ),\n  ),\n  1000 => \n  array (\n    'wp_admin_bar_render' => \n    array (\n      'function' => 'wp_admin_bar_render',\n      'accepted_args' => 1,\n    ),\n  ),\n)\n<\/code><\/pre>\n
To find and remove our evil action we have to go through the associated filters for the hook (an action is just a very simple filter), check if it is an array and if the object is an instance of the class. Then we take the priority and remove the filter, without ever seeing the real identifier<\/em>.<\/p>\n
Okay, let\u2019s put that into a function:<\/p>\n
if ( ! function_exists( 'remove_anonymous_object_filter' ) )\n{\n    \/**\n     * Remove an anonymous object filter.\n     *\n     * @param  string $tag    Hook name.\n     * @param  string $class  Class name\n     * @param  string $method Method name\n     * @return void\n     *\/\n    function remove_anonymous_object_filter( $tag, $class, $method )\n    {\n        $filters = $GLOBALS['wp_filter'][ $tag ];\n\n        if ( empty ( $filters ) )\n        {\n            return;\n        }\n\n        foreach ( $filters as $priority => $filter )\n        {\n            foreach ( $filter as $identifier => $function )\n            {\n                if ( is_array( $function)\n                    and is_a( $function['function'][0], $class )\n                    and $method === $function['function'][1]\n                )\n                {\n                    remove_filter(\n                        $tag,\n                        array ( $function['function'][0], $method ),\n                        $priority\n                    );\n                }\n            }\n        }\n    }\n}\n<\/code><\/pre>\n
When do we call this function? There is no way to know for sure when the original object is created. Maybe sometimes before 'plugins_loaded'<\/code>? Maybe later? <\/p>\n
We use just the same hook the object is associated to and jump in very early with priority 0<\/code>. That\u2019s the only way to be really sure. Here is how we would remove the method print_message_3()<\/code>:<\/p>\n
add_action( 'wp_footer', 'kill_anonymous_example', 0 );\n\nfunction kill_anonymous_example()\n{\n    remove_anonymous_object_filter(\n        'wp_footer',\n        'Anonymous_Object',\n        'print_message_3'\n    );\n}\n<\/code><\/pre>\n
Result:<\/p>\n
\"enter<\/p>\n
And that should remove the action from your question (not tested):<\/p>\n
add_action( 'comments_array', 'kill_FbComments', 0 );\n\nfunction kill_FbComments()\n{\n    remove_anonymous_object_filter(\n        'comments_array',\n        'SEOFacebookComments',\n        'FbComments'\n    );\n}\n<\/code><\/pre>\n
Conclusion<\/h2>\n