performance-lab / server-timing / load.php

load.php in Performance Lab 2.1.0, at server-timing/load.php

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1	<?php
2	/**
3	* Server-Timing API integration file
4	*
5	* @package performance-lab
6	* @since 1.8.0
7	*/
8
9	/**
10	* Provides access the Server-Timing API.
11	*
12	* When called for the first time, this also initializes the API to schedule the header for output.
13	* In case that no metrics are registered, this is still called on {@see 'wp_loaded'}, so that even then it still fires
14	* its action hooks as expected.
15	*
16	* @since 1.8.0
17	*/
18	function perflab_server_timing() {
19	static $server_timing;
20
21	if ( null === $server_timing ) {
22	$server_timing = new Perflab_Server_Timing();
23	add_filter( 'template_include', array( $server_timing, 'on_template_include' ), PHP_INT_MAX );
24	}
25
26	return $server_timing;
27	}
28	add_action( 'wp_loaded', 'perflab_server_timing' );
29
30	/**
31	* Registers a metric to calculate for the Server-Timing header.
32	*
33	* This method must be called before the {@see 'perflab_server_timing_send_header'} hook.
34	*
35	* @since 1.8.0
36	*
37	* @param string $metric_slug The metric slug.
38	* @param array $args {
39	* Arguments for the metric.
40	*
41	* @type callable $measure_callback The callback that initiates calculating the metric value. It will receive
42	* the Perflab_Server_Timing_Metric instance as a parameter, in order to set
43	* the value when it has been calculated. Metric values must be provided in
44	* milliseconds.
45	* @type string $access_cap Capability required to view the metric. If this is a public metric, this
46	* needs to be set to "exist".
47	* }
48	*/
49	function perflab_server_timing_register_metric( $metric_slug, array $args ) {
50	perflab_server_timing()->register_metric( $metric_slug, $args );
51	}
52
53	/**
54	* Returns whether an output buffer should be used to gather Server-Timing metrics during template rendering.
55	*
56	* @since 1.8.0
57	*
58	* @return bool True if an output buffer should be used, false otherwise.
59	*/
60	function perflab_server_timing_use_output_buffer() {
61	return perflab_server_timing()->use_output_buffer();
62	}
63
64	/**
65	* Wraps a callback (e.g. for an action or filter) to be measured and included in the Server-Timing header.
66	*
67	* @since 1.8.0
68	*
69	* @param callable $callback The callback to wrap.
70	* @param string $metric_slug The metric slug to use within the Server-Timing header.
71	* @param string $access_cap Capability required to view the metric. If this is a public metric, this needs to be
72	* set to "exist".
73	* @return callable Callback function that will run $callback and measure its execution time once called.
74	*/
75	function perflab_wrap_server_timing( $callback, $metric_slug, $access_cap ) {
76	return function( ...$callback_args ) use ( $callback, $metric_slug, $access_cap ) {
77	// Gain access to Perflab_Server_Timing_Metric instance.
78	$server_timing_metric = null;
79
80	// Only register the metric the first time the function is called.
81	// For now, this also means only the first function call is measured.
82	if ( ! perflab_server_timing()->has_registered_metric( $metric_slug ) ) {
83	perflab_server_timing_register_metric(
84	$metric_slug,
85	array(
86	'measure_callback' => function( $metric ) use ( &$server_timing_metric ) {
87	$server_timing_metric = $metric;
88	},
89	'access_cap' => $access_cap,
90	)
91	);
92	}
93
94	// If metric instance was not set, this metric should not be calculated.
95	if ( null === $server_timing_metric ) {
96	return call_user_func_array( $callback, $callback_args );
97	}
98
99	// Measure time before the callback.
100	$server_timing_metric->measure_before();
101
102	// Execute the callback.
103	$result = call_user_func_array( $callback, $callback_args );
104
105	// Measure time after the callback and calculate total.
106	$server_timing_metric->measure_after();
107
108	// Return result (e.g. in case this is a filter callback).
109	return $result;
110	};
111	}
112