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apply_filters › WordPress Function

Since0.71
Deprecatedn/a
› apply_filters ( $hook_name, $value, $args )
Parameters: (3)
  • (string) $hook_name The name of the filter hook.
    Required: Yes
  • (mixed) $value The value to filter.
    Required: Yes
  • (mixed) $args Optional. Additional parameters to pass to the callback functions.
    Required: Yes
Returns:
  • (mixed) The filtered value after all hooked functions are applied to it.
Defined at:
Codex:
Change Log:
  • 6.0.0

Calls the callback functions that have been added to a filter hook.

This function invokes all functions attached to filter hook $hook_name. It is possible to create new filter hooks by simply calling this function, specifying the name of the new hook using the $hook_name parameter. The function also allows for multiple additional arguments to be passed to hooks. Example usage: // The filter callback function. function example_callback( $string, $arg1, $arg2 ) { // (maybe) modify $string. return $string; } add_filter( 'example_filter', 'example_callback', 10, 3 ); / Apply the filters by calling the 'example_callback()' function that's hooked onto example_filter above. - 'example_filter' is the filter hook. - 'filter me' is the value being filtered. * - $arg1 and $arg2 are the additional arguments passed to the callback. $value = apply_filters( 'example_filter', 'filter me', $arg1, $arg2 );


Related Functions: apply_filters_ref_array, add_filter, apply_filters_deprecated, has_filter, wp_list_filter

Source 

function apply_filters( $hook_name, $value, ...$args ) {
	global $wp_filter, $wp_filters, $wp_current_filter;

	if ( ! isset( $wp_filters[ $hook_name ] ) ) {
		$wp_filters[ $hook_name ] = 1;
	} else {
		++$wp_filters[ $hook_name ];
	}

	// Do 'all' actions first.
	if ( isset( $wp_filter['all'] ) ) {
		$wp_current_filter[] = $hook_name;

		$all_args = func_get_args(); // phpcs:ignore PHPCompatibility.FunctionUse.ArgumentFunctionsReportCurrentValue.NeedsInspection
		_wp_call_all_hook( $all_args );
	}

	if ( ! isset( $wp_filter[ $hook_name ] ) ) {
		if ( isset( $wp_filter['all'] ) ) {
			array_pop( $wp_current_filter );
		}

		return $value;
	}

	if ( ! isset( $wp_filter['all'] ) ) {
		$wp_current_filter[] = $hook_name;
	}

	// Pass the value to WP_Hook.
	array_unshift( $args, $value );

	$filtered = $wp_filter[ $hook_name ]->apply_filters( $value, $args );

	array_pop( $wp_current_filter );

	return $filtered;
}