wp_before_load_template │ action-hook │ WP 6.1.0

Fires before a template is included (output).

locate_template() is a low-level template inclusion function on which functions such as get_template_part(), get_header(), get_footer(), and others are based.

Together, the wp_before_load_template and wp_after_load_template events can, for example, measure the time required to include (generate) a template; see the example.

Usage

add_action( 'wp_before_load_template', 'wp_kama_before_load_template_action', 10, 3 );

/**
 * Function for `wp_before_load_template` action-hook.
 * 
 * @param string $_template_file The full path to the template file.
 * @param bool   $load_once      Whether to require_once or require.
 * @param array  $args           Additional arguments passed to the template.
 *
 * @return void
 */
function wp_kama_before_load_template_action( $_template_file, $load_once, $args ){

	// action...
}

$_template_file(string)

Full path to the template file, for example /home/site/www/wp-content/themes/mytheme/myfile.php.

$load_once(true|false)

true when the template was included with require_once.
false when the template was included with require.

$args(array)

Additional arguments passed to the included file.

Examples

#1 Measure the inclusion (generation) time of each template file

// Before including the template.
add_action( 'wp_before_load_template', 'wpkama_load_template_timer' );

// After including the template.
add_action( 'wp_after_load_template', 'wpkama_load_template_timer' );

// Output the collected data to the log file.
register_shutdown_function( 'wpkama_load_template_timer' );

function wpkama_load_template_timer( $file = null ){
	static $files_start_times = [];
	static $result = [];

	if( doing_action( 'wp_before_load_template' ) ){
		$files_start_times[ $file ] = microtime( true );
		return;
	}

	if( doing_action( 'wp_after_load_template' ) ){
		$result[ $file ][] = sprintf( '%.6f sec.', microtime( true ) - $files_start_times[ $file ] );
		return;
	}

	// Shutdown.
	error_log( print_r( $result, true ) );
}

The log file contains the following data. The ellipsis replaces the beginning of each full file path for brevity:

Array
(
	[.../templates/parts/header/svg.php] => Array
		(
			[0] => 0.000394 sec.
		)

	[.../templates/parts/header/header.php] => Array
		(
			[0] => 0.010713 sec.
		)

	[.../templates/event/archive/parts/event-card-full.php] => Array
		(
			[0] => 0.000572 sec.
			[1] => 0.000530 sec.
		)

	[.../templates/event/single/parts/upcoming-events.php] => Array
		(
			[0] => 0.006188 sec.
		)

	[.../templates/event/single/parts/schedule.php] => Array
		(
			[0] => 0.000237 sec.
		)

	[.../templates/parts/btn-to-top.php] => Array
		(
			[0] => 0.000124 sec.
		)

	[.../templates/parts/footer/footer.php] => Array
		(
			[0] => 0.005845 sec.
		)

)