optimization-detective / optimization.php

optimization.php in Optimization Detective trunk, at optimization.php

369 lines 13.1 KB

Raw Download Zip

1	<?php
2	/**
3	* Optimizing for Optimization Detective.
4	*
5	* @package optimization-detective
6	* @since 0.1.0
7	*/
8
9	declare( strict_types = 1 );
10
11	// @codeCoverageIgnoreStart
12	if ( ! defined( 'ABSPATH' ) ) {
13	exit; // Exit if accessed directly.
14	}
15	// @codeCoverageIgnoreEnd
16
17	/**
18	* Starts output buffering at the end of the 'template_include' filter.
19	*
20	* This is to implement #43258 in core.
21	*
22	* This is a hack that would eventually be replaced with something like this in wp-includes/template-loader.php:
23	*
24	* $template = apply_filters( 'template_include', $template );
25	* + ob_start( 'wp_template_output_buffer_callback' );
26	* if ( $template ) {
27	* include $template;
28	* } elseif ( current_user_can( 'switch_themes' ) ) {
29	*
30	* @since 0.1.0
31	* @access private
32	* @link https://core.trac.wordpress.org/ticket/43258
33	*
34	* @param string\|mixed $passthrough Value for the template_include filter which is passed through.
35	* @return string\|mixed Unmodified value of $passthrough.
36	*/
37	function od_buffer_output( $passthrough ) {
38	/*
39	* Instead of the default PHP_OUTPUT_HANDLER_STDFLAGS (cleanable, flushable, and removable) being used for flags,
40	* we need to omit PHP_OUTPUT_HANDLER_FLUSHABLE. If the buffer were flushable, then each time that ob_flush() is
41	* called, it would send a fragment of the output into the output buffer callback. When buffering the entire
42	* response as an HTML document, this would result in broken HTML processing.
43	*
44	* If this ends up being problematic, then PHP_OUTPUT_HANDLER_FLUSHABLE could be added to the $flags and the
45	* output buffer callback could check if the phase is PHP_OUTPUT_HANDLER_FLUSH and abort any later
46	* processing while also emitting a _doing_it_wrong().
47	*
48	* The output buffer needs to be removable because WordPress calls wp_ob_end_flush_all() and then calls
49	* wp_cache_close(). If the buffers are not all flushed before wp_cache_close() is closed, then some output buffer
50	* handlers (e.g. for caching plugins) may fail to be able to store the page output in the object cache.
51	* See <https://github.com/WordPress/performance/pull/1317#issuecomment-2271955356>.
52	*/
53	$flags = PHP_OUTPUT_HANDLER_STDFLAGS ^ PHP_OUTPUT_HANDLER_FLUSHABLE;
54
55	ob_start(
56	static function ( string $output, ?int $phase ): string {
57	// When the output is being cleaned (e.g. the pending template is replaced with an error page), do not send it through the filter.
58	if ( ( $phase & PHP_OUTPUT_HANDLER_CLEAN ) !== 0 ) {
59	return $output;
60	}
61
62	/**
63	* Filters the template output buffer before sending it to the client.
64	*
65	* @since 0.1.0
66	* @link https://github.com/WordPress/performance/blob/trunk/plugins/optimization-detective/docs/hooks.md#:~:text=Filter%3A%20od_template_output_buffer
67	*
68	* @param string $output Output buffer.
69	* @return string Filtered output buffer.
70	*/
71	return (string) apply_filters( 'od_template_output_buffer', $output );
72	},
73	0, // Unlimited buffer size.
74	$flags
75	);
76	return $passthrough;
77	}
78
79	/**
80	* Adds template output buffer filter for optimization if eligible.
81	*
82	* @since 0.1.0
83	* @access private
84	*/
85	function od_maybe_add_template_output_buffer_filter(): void {
86	$disabled_reasons = od_get_disabled_reasons();
87	if ( count( $disabled_reasons ) > 0 ) {
88	if ( WP_DEBUG ) {
89	add_action(
90	'wp_print_footer_scripts',
91	static function () use ( $disabled_reasons ): void {
92	od_print_disabled_reasons( array_values( $disabled_reasons ) );
93	}
94	);
95	}
96	return;
97	}
98
99	$callback = 'od_optimize_template_output_buffer';
100	if (
101	function_exists( 'perflab_wrap_server_timing' )
102	&&
103	function_exists( 'perflab_server_timing_use_output_buffer' )
104	&&
105	perflab_server_timing_use_output_buffer()
106	) {
107	$callback = perflab_wrap_server_timing( $callback, 'optimization-detective', 'exist' );
108	}
109	add_filter( 'od_template_output_buffer', $callback );
110	}
111
112	/**
113	* Prints the reasons why Optimization Detective is not optimizing the current page.
114	*
115	* This is only used when WP_DEBUG is enabled.
116	*
117	* @since 1.0.0
118	* @access private
119	*
120	* @param string[] $reasons Reason messages.
121	*/
122	function od_print_disabled_reasons( array $reasons ): void {
123	foreach ( $reasons as $i => $reason ) {
124	wp_print_inline_script_tag(
125	sprintf(
126	"console.info( %s );\n//# sourceURL=od-print-disabled-reasons-%d",
127	(string) wp_json_encode( '[Optimization Detective] ' . $reason, JSON_HEX_TAG \| JSON_UNESCAPED_SLASHES ),
128	$i + 1
129	),
130	array( 'type' => 'module' )
131	);
132	}
133	}
134
135	/**
136	* Determines whether the current response can be optimized.
137	*
138	* @since 0.1.0
139	* @since 0.9.0 Response is optimized for admin users as well when in 'plugin' development mode.
140	*
141	* @access private
142	*
143	* @return bool Whether response can be optimized.
144	*/
145	function od_can_optimize_response(): bool {
146	return count( od_get_disabled_reasons() ) === 0;
147	}
148
149	/**
150	* Determines whether the response has an HTML Content-Type.
151	*
152	* @since 0.2.0
153	* @private
154	*
155	* @return bool Whether Content-Type is HTML.
156	*/
157	function od_is_response_html_content_type(): bool {
158	$is_html_content_type = false;
159
160	$headers_list = array_merge(
161	array( 'Content-Type: ' . ini_get( 'default_mimetype' ) ),
162	headers_list()
163	);
164	foreach ( $headers_list as $header ) {
165	$header_parts = preg_split( '/\s[:;]\s/', strtolower( $header ) );
166	if ( is_array( $header_parts ) && count( $header_parts ) >= 2 && 'content-type' === $header_parts[0] ) {
167	$is_html_content_type = in_array( $header_parts[1], array( 'text/html', 'application/xhtml+xml' ), true );
168	}
169	}
170
171	return $is_html_content_type;
172	}
173
174	/**
175	* Optimizes template output buffer.
176	*
177	* @since 0.1.0
178	* @access private
179	*
180	* @global WP_Query $wp_the_query WP_Query object.
181	*
182	* @param string $buffer Template output buffer.
183	* @return string Filtered template output buffer.
184	*/
185	function od_optimize_template_output_buffer( string $buffer ): string {
186	global $wp_the_query;
187
188	// If the content-type is not HTML or the output does not start with '<', then abort since the buffer is definitely not HTML.
189	if (
190	! od_is_response_html_content_type() \|\|
191	! str_starts_with( ltrim( $buffer ), '<' )
192	) {
193	return $buffer;
194	}
195
196	// If the initial tag is not an open HTML tag, then abort since the buffer is not a complete HTML document.
197	$processor = new OD_HTML_Tag_Processor( $buffer );
198	if ( ! (
199	$processor->next_tag( array( 'tag_closers' => 'visit' ) ) &&
200	! $processor->is_tag_closer() &&
201	'HTML' === $processor->get_tag()
202	) ) {
203	return $buffer;
204	}
205
206	$query_vars = od_get_normalized_query_vars();
207	$slug = od_get_url_metrics_slug( $query_vars );
208	$post = OD_URL_Metrics_Post_Type::get_post( $slug );
209
210	/**
211	* Post ID.
212	*
213	* @var positive-int\|null $post_id
214	*/
215	$post_id = $post instanceof WP_Post ? $post->ID : null;
216
217	$tag_visitor_registry = new OD_Tag_Visitor_Registry();
218
219	/**
220	* Fires to register tag visitors before walking over the document to perform optimizations.
221	*
222	* @since 0.3.0
223	* @link https://github.com/WordPress/performance/blob/trunk/plugins/optimization-detective/docs/hooks.md#:~:text=Action%3A%20od_register_tag_visitors
224	*
225	* @param OD_Tag_Visitor_Registry $tag_visitor_registry Tag visitor registry.
226	*/
227	do_action( 'od_register_tag_visitors', $tag_visitor_registry );
228
229	$current_etag = od_get_current_url_metrics_etag( $tag_visitor_registry, $wp_the_query, od_get_current_theme_template() );
230	$group_collection = new OD_URL_Metric_Group_Collection(
231	$post instanceof WP_Post ? OD_URL_Metrics_Post_Type::get_url_metrics_from_post( $post ) : array(),
232	$current_etag,
233	od_get_breakpoint_max_widths(),
234	od_get_url_metrics_breakpoint_sample_size(),
235	od_get_url_metric_freshness_ttl()
236	);
237	$link_collection = new OD_Link_Collection();
238
239	$template_optimization_context = new OD_Template_Optimization_Context(
240	$group_collection,
241	$link_collection,
242	$query_vars,
243	$slug,
244	$post_id
245	);
246
247	/**
248	* Fires before Optimization Detective starts iterating over the document in the output buffer.
249	*
250	* This is before any of the registered tag visitors have been invoked.
251	*
252	* @since 1.0.0
253	* @link https://github.com/WordPress/performance/blob/trunk/plugins/optimization-detective/docs/hooks.md#:~:text=Action%3A%20od_start_template_optimization
254	*
255	* @param OD_Template_Optimization_Context $template_optimization_context Template optimization context.
256	*/
257	do_action( 'od_start_template_optimization', $template_optimization_context );
258
259	$visited_tag_state = new OD_Visited_Tag_State();
260	$tag_visitor_context = new OD_Tag_Visitor_Context(
261	$processor,
262	$group_collection,
263	$link_collection,
264	$visited_tag_state,
265	$post_id
266	);
267	$current_tag_bookmark = 'optimization_detective_current_tag';
268	$visitors = iterator_to_array( $tag_visitor_registry );
269
270	// Whether we need to add the data-od-xpath attribute to elements and whether the detection script should be injected.
271	$needs_detection = ! $group_collection->is_every_group_complete();
272	$did_amend_meta_generator = false;
273	do {
274	// Never process anything inside NOSCRIPT since it will never show up in the DOM when scripting is enabled, and thus it can never be detected nor measured.
275	// Similarly, elements in the Admin Bar are not relevant for optimization, so this loop ensures that no tags in the Admin Bar are visited.
276	if (
277	in_array( 'NOSCRIPT', $processor->get_breadcrumbs(), true )
278	\|\|
279	$processor->is_admin_bar()
280	) {
281	continue;
282	}
283
284	// Amend the META generator tag if it's the right one and hasn't been amended already.
285	if (
286	! $did_amend_meta_generator && // @phpstan-ignore booleanNot.alwaysTrue, booleanAnd.alwaysFalse, booleanAnd.alwaysFalse, booleanAnd.alwaysFalse (False positives in PHPStan due to the following line.)
287	'META' === $processor->get_tag() && // @phpstan-ignore identical.alwaysFalse (False positive in PHPStan since it isn't aware of the do/while loop apparently.)
288	'generator' === $processor->get_attribute( 'name' ) &&
289	str_starts_with( (string) $processor->get_attribute( 'content' ), 'optimization-detective ' )
290	) {
291	$content = (string) $processor->get_attribute( 'content' );
292	$viewport_group_status = array();
293	foreach ( $group_collection as $group ) {
294	$min_width = $group->get_minimum_viewport_width();
295
296	$status = 'empty';
297	if ( $group->is_complete() ) {
298	$status = 'complete';
299	} elseif ( $group->count() > 0 ) {
300	$status = 'populated';
301	}
302
303	$viewport_group_status[] = sprintf( '%s:%s', $min_width, $status );
304	}
305	$content .= '; url_metric_groups={' . implode( ', ', $viewport_group_status ) . '}';
306	$processor->set_attribute( 'content', $content );
307	$did_amend_meta_generator = true;
308	}
309
310	$tracked_in_url_metrics = false;
311	$processor->set_bookmark( $current_tag_bookmark ); // TODO: Should we break if this returns false?
312
313	foreach ( $visitors as $visitor ) {
314	$cursor_move_count = $processor->get_cursor_move_count();
315	$visitor_return_value = $visitor( $tag_visitor_context );
316	if ( true === $visitor_return_value ) {
317	$tracked_in_url_metrics = true;
318	}
319
320	// If the visitor traversed HTML tags, we need to go back to this tag so that in the next iteration any
321	// relevant tag visitors may apply, in addition to properly setting the data-od-xpath on this tag below.
322	if ( $cursor_move_count !== $processor->get_cursor_move_count() ) {
323	$processor->seek( $current_tag_bookmark ); // TODO: Should this break out of the optimization loop if it returns false?
324	}
325	}
326	$processor->release_bookmark( $current_tag_bookmark );
327
328	if ( $visited_tag_state->is_tag_tracked() ) {
329	$tracked_in_url_metrics = true;
330	}
331
332	if ( $tracked_in_url_metrics && $needs_detection ) {
333	$processor->set_meta_attribute( 'xpath', $processor->get_xpath() );
334	}
335
336	$visited_tag_state->reset();
337	} while ( $processor->next_tag( array( 'tag_closers' => 'skip' ) ) );
338
339	// Inject detection script.
340	// TODO: When optimizing above, if we find that there is a stored LCP element but it fails to match, it should perhaps set $needs_detection to true and send the request with an override nonce. However, this would require backtracking and adding the data-od-xpath attributes.
341	if ( $needs_detection ) {
342	$processor->append_body_html( od_get_detection_scripts( $slug, $group_collection ) );
343	}
344
345	/**
346	* Fires after Optimization Detective has finished iterating over the document in the output buffer.
347	*
348	* This is after all the registered tag visitors have been invoked.
349	*
350	* @since 1.0.0
351	* @link https://github.com/WordPress/performance/blob/trunk/plugins/optimization-detective/docs/hooks.md#:~:text=Action%3A-,od_finish_template_optimization
352	*
353	* @param OD_Template_Optimization_Context $template_optimization_context Template optimization context.
354	*/
355	do_action( 'od_finish_template_optimization', $template_optimization_context );
356
357	// Send any preload links in a Link response header and in a LINK tag injected at the end of the HEAD.
358	// Additional links may have been added at the od_finish_template_optimization action, so this must come after.
359	if ( count( $link_collection ) > 0 ) {
360	$response_header_links = $link_collection->get_response_header();
361	if ( ! is_null( $response_header_links ) && ! headers_sent() ) {
362	header( $response_header_links, false );
363	}
364	$processor->append_head_html( $link_collection->get_html() );
365	}
366
367	return $processor->get_updated_html();
368	}
369