powered-cache / includes / dropins / redis-object-cache.php

redis-object-cache.php in Powered Cache – Caching and Optimization for WordPress – Easily Improve PageSpeed & Web Vitals Score 3.6, at includes/dropins/redis-object-cache.php

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1	<?php
2
3	// WP Redis
4	// This file needs to be symlinked or copied to wp-content/object-cache.php
5
6	// Users with setups where multiple installs share a common wp-config.php or $table_prefix
7	// can use this to guarantee uniqueness for the keys generated by this object cache.
8	if ( ! defined( 'WP_CACHE_KEY_SALT' ) ) {
9	define( 'WP_CACHE_KEY_SALT', '' );
10	}
11
12	if ( ! defined( 'WP_REDIS_OBJECT_CACHE' ) ) {
13	define( 'WP_REDIS_OBJECT_CACHE', true );
14	}
15
16	if ( ! defined( 'WP_REDIS_USE_CACHE_GROUPS' ) ) {
17	define( 'WP_REDIS_USE_CACHE_GROUPS', false );
18	}
19
20	if ( ! defined( 'WP_REDIS_DEFAULT_EXPIRE_SECONDS' ) ) {
21	define( 'WP_REDIS_DEFAULT_EXPIRE_SECONDS', 0 );
22	}
23
24	if ( ! defined( 'WP_REDIS_IGNORE_GLOBAL_GROUPS' ) ) {
25	define( 'WP_REDIS_IGNORE_GLOBAL_GROUPS', false );
26	}
27
28	/**
29	* Adds data to the cache, if the cache key doesn't already exist.
30	*
31	* @uses $wp_object_cache Object Cache Class
32	* @see WP_Object_Cache::add()
33	*
34	* @param int\|string $key The cache key to use for retrieval later
35	* @param mixed $data The data to add to the cache store
36	* @param string $group The group to add the cache to
37	* @param int $expire When the cache data should be expired
38	* @return bool False if cache key and group already exist, true on success
39	*/
40	function wp_cache_add( $key, $data, $group = '', $expire = WP_REDIS_DEFAULT_EXPIRE_SECONDS ) {
41	global $wp_object_cache;
42
43	return $wp_object_cache->add( $key, $data, $group, (int) $expire );
44	}
45
46	/**
47	* Closes the cache.
48	*
49	* This function has ceased to do anything since WordPress 2.5. The
50	* functionality was removed along with the rest of the persistent cache. This
51	* does not mean that plugins can't implement this function when they need to
52	* make sure that the cache is cleaned up after WordPress no longer needs it.
53	*
54	* @return bool Always returns True
55	*/
56	function wp_cache_close() {
57	return true;
58	}
59
60	/**
61	* Decrement numeric cache item's value
62	*
63	* @uses $wp_object_cache Object Cache Class
64	* @see WP_Object_Cache::decr()
65	*
66	* @param int\|string $key The cache key to increment
67	* @param int $offset The amount by which to decrement the item's value. Default is 1.
68	* @param string $group The group the key is in.
69	* @return false\|int False on failure, the item's new value on success.
70	*/
71	function wp_cache_decr( $key, $offset = 1, $group = '' ) {
72	global $wp_object_cache;
73
74	return $wp_object_cache->decr( $key, $offset, $group );
75	}
76
77	/**
78	* Removes the cache contents matching key and group.
79	*
80	* @uses $wp_object_cache Object Cache Class
81	* @see WP_Object_Cache::delete()
82	*
83	* @param int\|string $key What the contents in the cache are called
84	* @param string $group Where the cache contents are grouped
85	* @return bool True on successful removal, false on failure
86	*/
87	function wp_cache_delete( $key, $group = '' ) {
88	global $wp_object_cache;
89
90	return $wp_object_cache->delete( $key, $group );
91	}
92
93	/**
94	* Removes cache contents for a given group.
95	*
96	* @uses $wp_object_cache Object Cache Class
97	* @see WP_Object_Cache::delete_group()
98	*
99	* @param string $group Where the cache contents are grouped
100	* @return bool True on successful removal, false on failure
101	*/
102	function wp_cache_delete_group( $group ) {
103	global $wp_object_cache;
104	return $wp_object_cache->delete_group( $group );
105	}
106
107
108	/**
109	* Removes all cache items.
110	*
111	* @uses $wp_object_cache Object Cache Class
112	* @see WP_Object_Cache::flush()
113	*
114	* @return bool False on failure, true on success
115	*/
116	function wp_cache_flush() {
117	global $wp_object_cache;
118
119	return $wp_object_cache->flush();
120	}
121
122	/**
123	* Retrieves the cache contents from the cache by key and group.
124	*
125	* @uses $wp_object_cache Object Cache Class
126	* @see WP_Object_Cache::get()
127	*
128	* @param int\|string $key What the contents in the cache are called
129	* @param string $group Where the cache contents are grouped
130	* @param bool $force Whether to force an update of the local cache from the persistent cache (default is false)
131	* @param &bool $found Whether key was found in the cache. Disambiguates a return of false, a storable value.
132	* @return bool\|mixed False on failure to retrieve contents or the cache contents on success
133	*/
134	function wp_cache_get( $key, $group = '', $force = false, &$found = null ) {
135	global $wp_object_cache;
136
137	return $wp_object_cache->get( $key, $group, $force, $found );
138	}
139
140	/**
141	* Retrieves multiple values from the cache in one call.
142	*
143	* @see WP_Object_Cache::get_multiple()
144	* @global WP_Object_Cache $wp_object_cache Object cache global instance.
145	*
146	* @param array $keys Array of keys under which the cache contents are stored.
147	* @param string $group Optional. Where the cache contents are grouped. Default empty.
148	* @param bool $force Optional. Whether to force an update of the local cache
149	* from the persistent cache. Default false.
150	* @return array Array of values organized into groups.
151	*/
152	function wp_cache_get_multiple( $keys, $group = '', $force = false ) {
153	global $wp_object_cache;
154
155	return $wp_object_cache->get_multiple( $keys, $group, $force );
156	}
157
158	/**
159	* Removes all cache items from the in-memory runtime cache.
160	*
161	* @see WP_Object_Cache::flush()
162	*
163	* @return bool True on success, false on failure.
164	*/
165	function wp_cache_flush_runtime() {
166	global $wp_object_cache;
167
168	return $wp_object_cache->flush( false );
169	}
170
171	/**
172	* Removes all cache items in a group, if the object cache implementation supports it.
173	*
174	* Before calling this function, always check for group flushing support using the
175	* `wp_cache_supports( 'flush_group' )` function.
176	*
177	* @see WP_Object_Cache::flush_group()
178	* @global WP_Object_Cache $wp_object_cache Object cache global instance.
179	*
180	* @param string $group Name of group to remove from cache.
181	* @return bool True if group was flushed, false otherwise.
182	*/
183	function wp_cache_flush_group( $group ) {
184	global $wp_object_cache;
185
186	return $wp_object_cache->flush_group( $group );
187	}
188
189
190	/**
191	* Increment numeric cache item's value
192	*
193	* @uses $wp_object_cache Object Cache Class
194	* @see WP_Object_Cache::incr()
195	*
196	* @param int\|string $key The cache key to increment
197	* @param int $offset The amount by which to increment the item's value. Default is 1.
198	* @param string $group The group the key is in.
199	* @return false\|int False on failure, the item's new value on success.
200	*/
201	function wp_cache_incr( $key, $offset = 1, $group = '' ) {
202	global $wp_object_cache;
203
204	return $wp_object_cache->incr( $key, $offset, $group );
205	}
206
207	/**
208	* Sets up Object Cache Global and assigns it.
209	*
210	* @global WP_Object_Cache $wp_object_cache WordPress Object Cache
211	*/
212	function wp_cache_init() {
213	global $wp_object_cache;
214
215	if ( ! ( $wp_object_cache instanceof WP_Object_Cache ) ) {
216	$wp_object_cache = new WP_Object_Cache;
217	}
218	}
219
220	/**
221	* Replaces the contents of the cache with new data.
222	*
223	* @uses $wp_object_cache Object Cache Class
224	* @see WP_Object_Cache::replace()
225	*
226	* @param int\|string $key What to call the contents in the cache
227	* @param mixed $data The contents to store in the cache
228	* @param string $group Where to group the cache contents
229	* @param int $expire When to expire the cache contents
230	* @return bool False if not exists, true if contents were replaced
231	*/
232	function wp_cache_replace( $key, $data, $group = '', $expire = WP_REDIS_DEFAULT_EXPIRE_SECONDS ) {
233	global $wp_object_cache;
234
235	return $wp_object_cache->replace( $key, $data, $group, (int) $expire );
236	}
237
238	/**
239	* Saves the data to the cache.
240	*
241	* @uses $wp_object_cache Object Cache Class
242	* @see WP_Object_Cache::set()
243	*
244	* @param int\|string $key What to call the contents in the cache
245	* @param mixed $data The contents to store in the cache
246	* @param string $group Where to group the cache contents
247	* @param int $expire When to expire the cache contents
248	* @return bool False on failure, true on success
249	*/
250	function wp_cache_set( $key, $data, $group = '', $expire = WP_REDIS_DEFAULT_EXPIRE_SECONDS ) {
251	global $wp_object_cache;
252
253	return $wp_object_cache->set( $key, $data, $group, (int) $expire );
254	}
255
256	/**
257	* Switch the internal blog id.
258	*
259	* This changes the blog id used to create keys in blog specific groups.
260	*
261	* @param int $blog_id Blog ID
262	*/
263	function wp_cache_switch_to_blog( $blog_id ) {
264	global $wp_object_cache;
265
266	return $wp_object_cache->switch_to_blog( $blog_id );
267	}
268
269	/**
270	* Adds a group or set of groups to the list of global groups.
271	*
272	* @param string\|array $groups A group or an array of groups to add
273	*/
274	function wp_cache_add_global_groups( $groups ) {
275	global $wp_object_cache;
276
277	return $wp_object_cache->add_global_groups( $groups );
278	}
279
280	/**
281	* Adds a group or set of groups to the list of non-persistent groups.
282	*
283	* @param string\|array $groups A group or an array of groups to add
284	*/
285	function wp_cache_add_non_persistent_groups( $groups ) {
286	global $wp_object_cache;
287
288	$wp_object_cache->add_non_persistent_groups( $groups );
289	}
290
291	/**
292	* Adds a group or set of groups to the list of groups that use Redis hashes.
293	*
294	* @param string\|array $groups A group or an array of groups to add.
295	*/
296	function wp_cache_add_redis_hash_groups( $groups ) {
297	global $wp_object_cache;
298
299	$wp_object_cache->add_redis_hash_groups( $groups );
300	}
301
302	/**
303	* Reset internal cache keys and structures. If the cache backend uses global
304	* blog or site IDs as part of its cache keys, this function instructs the
305	* backend to reset those keys and perform any cleanup since blog or site IDs
306	* have changed since cache init.
307	*
308	* This function is deprecated. Use wp_cache_switch_to_blog() instead of this
309	* function when preparing the cache for a blog switch. For clearing the cache
310	* during unit tests, consider using wp_cache_init(). wp_cache_init() is not
311	* recommended outside of unit tests as the performance penalty for using it is
312	* high.
313	*
314	* @deprecated 3.5.0
315	*/
316	function wp_cache_reset() {
317	_deprecated_function( __FUNCTION__, '3.5' );
318
319	global $wp_object_cache;
320
321	return $wp_object_cache->reset();
322	}
323
324	/**
325	* Determines whether the object cache implementation supports a particular feature.
326	*
327	* @since 6.1.0
328	*
329	* @param string $feature Name of the feature to check for. Possible values include:
330	* 'add_multiple', 'set_multiple', 'get_multiple', 'delete_multiple',
331	* 'flush_runtime', 'flush_group'.
332	* @return bool True if the feature is supported, false otherwise.
333	*/
334	function wp_cache_supports( $feature ) {
335	switch ( $feature ) {
336	case 'get_multiple':
337	case 'flush_runtime':
338	case 'flush_group':
339	return true;
340
341	case 'add_multiple':
342	case 'set_multiple':
343	case 'delete_multiple':
344	default:
345	return false;
346	}
347	}
348
349	/**
350	* WordPress Object Cache
351	*
352	* The WordPress Object Cache is used to save on trips to the database. The
353	* Object Cache stores all of the cache data to memory and makes the cache
354	* contents available by using a key, which is used to name and later retrieve
355	* the cache contents.
356	*
357	* The Object Cache can be replaced by other caching mechanisms by placing files
358	* in the wp-content folder which is looked at in wp-settings. If that file
359	* exists, then this file will not be included.
360	*/
361	#[AllowDynamicProperties]
362	class WP_Object_Cache {
363
364	/**
365	* Holds the cached objects
366	*
367	* @var array
368	*/
369	public $cache = [];
370
371	/**
372	* The amount of times the cache data was already stored in the cache.
373	*
374	* @var int
375	*/
376	public $cache_hits = 0;
377
378	/**
379	* Amount of times the cache did not have the request in cache
380	*
381	* @var int
382	*/
383	public $cache_misses = 0;
384
385	/**
386	* The amount of times a request was made to Redis
387	*
388	* @var int
389	*/
390	public $redis_calls = [];
391
392	/**
393	* List of global groups
394	*
395	* @var array
396	*/
397	public $global_groups = [];
398
399	/**
400	* List of non-persistent groups
401	*
402	* @var array
403	*/
404	public $non_persistent_groups = [];
405
406	/**
407	* List of groups which use Redis hashes.
408	*
409	* @var array
410	*/
411	public $redis_hash_groups = [];
412
413	/**
414	* The blog prefix to prepend to keys in non-global groups.
415	*
416	* @var int
417	*/
418	public $blog_prefix;
419
420	/**
421	* Whether or not Redis is connected
422	*
423	* @var bool
424	*/
425	public $is_redis_connected = false;
426
427	/**
428	* Whether or not the object cache thinks Redis needs a flush
429	*
430	* @var bool
431	*/
432	public $do_redis_failback_flush = false;
433
434	/**
435	* The last triggered error
436	*
437	* @var string
438	*/
439	public $last_triggered_error = '';
440
441	/**
442	* The missing redis message.
443	*
444	* @var string
445	*/
446	public $missing_redis_message = '';
447
448	/**
449	* Whether or not to use true cache groups, instead of flattening.
450	*
451	* @var bool
452	*/
453	const USE_GROUPS = WP_REDIS_USE_CACHE_GROUPS;
454
455	/**
456	* Adds data to the cache if it doesn't already exist.
457	*
458	* @uses WP_Object_Cache::_exists Checks to see if the cache already has data.
459	* @uses WP_Object_Cache::set Sets the data after the checking the cache
460	* contents existence.
461	*
462	* @param int\|string $key What to call the contents in the cache
463	* @param mixed $data The contents to store in the cache
464	* @param string $group Where to group the cache contents
465	* @param int $expire When to expire the cache contents
466	* @return bool False if cache key and group already exist, true on success
467	*/
468	public function add( $key, $data, $group = 'default', $expire = WP_REDIS_DEFAULT_EXPIRE_SECONDS ) {
469
470	if ( empty( $group ) ) {
471	$group = 'default';
472	}
473
474	if ( function_exists( 'wp_suspend_cache_addition' ) && wp_suspend_cache_addition() ) {
475	return false;
476	}
477
478	if ( $this->_exists( $key, $group ) ) {
479	return false;
480	}
481
482	return $this->set( $key, $data, $group, (int) $expire );
483	}
484
485	/**
486	* Sets the list of global groups.
487	*
488	* @param array $groups List of groups that are global.
489	*/
490	public function add_global_groups( $groups ) {
491	$groups = (array) $groups;
492
493	// Allow force ignoring of global groups.
494	if ( is_array( WP_REDIS_IGNORE_GLOBAL_GROUPS ) ) {
495	$groups = array_diff( $groups, WP_REDIS_IGNORE_GLOBAL_GROUPS );
496	}
497
498	$groups = array_fill_keys( $groups, true );
499	$this->global_groups = array_merge( $this->global_groups, $groups );
500	}
501
502	/**
503	* Sets the list of non-persistent groups.
504	*
505	* @param array $groups List of groups that are non-persistent.
506	*/
507	public function add_non_persistent_groups( $groups ) {
508	$groups = (array) $groups;
509
510	$groups = array_fill_keys( $groups, true );
511	$this->non_persistent_groups = array_merge( $this->non_persistent_groups, $groups );
512	}
513
514	/**
515	* Sets the list of groups that use Redis hashes.
516	*
517	* @param array $groups List of groups that use Redis hashes.
518	*/
519	public function add_redis_hash_groups( $groups ) {
520	$groups = (array) $groups;
521
522	$groups = array_fill_keys( $groups, true );
523	$this->redis_hash_groups = array_merge( $this->redis_hash_groups, $groups );
524	}
525
526	/**
527	* Decrement numeric cache item's value
528	*
529	* @param int\|string $key The cache key to increment
530	* @param int $offset The amount by which to decrement the item's value. Default is 1.
531	* @param string $group The group the key is in.
532	* @return false\|int False on failure, the item's new value on success.
533	*/
534	public function decr( $key, $offset = 1, $group = 'default' ) {
535
536	if ( empty( $group ) ) {
537	$group = 'default';
538	}
539
540	// The key needs to exist in order to be decremented
541	if ( ! $this->_exists( $key, $group ) ) {
542	return false;
543	}
544
545	$offset = (int) $offset;
546
547	// If this isn't a persistent group, we have to sort this out ourselves, grumble grumble.
548	if ( ! $this->_should_persist( $group ) ) {
549	$existing = $this->_get_internal( $key, $group );
550	if ( empty( $existing ) \|\| ! is_numeric( $existing ) ) {
551	$existing = 0;
552	} else {
553	$existing -= $offset;
554	}
555	if ( $existing < 0 ) {
556	$existing = 0;
557	}
558	$this->_set_internal( $key, $group, $existing );
559	return $existing;
560	}
561
562	if ( $this->_should_use_redis_hashes( $group ) ) {
563	$redis_safe_group = $this->_key( '', $group );
564	$result = $this->_call_redis( 'hIncrBy', $redis_safe_group, $key, -$offset, $group );
565	if ( $result < 0 ) {
566	$result = 0;
567	$this->_call_redis( 'hSet', $redis_safe_group, $key, $result );
568	}
569	} else {
570	$id = $this->_key( $key, $group );
571	$result = $this->_call_redis( 'decrBy', $id, $offset );
572	if ( $result < 0 ) {
573	$result = 0;
574	$this->_call_redis( 'set', $id, $result );
575	}
576	}
577
578	if ( is_int( $result ) ) {
579	$this->_set_internal( $key, $group, $result );
580	}
581	return $result;
582	}
583
584	/**
585	* Remove the contents of the cache key in the group
586	*
587	* If the cache key does not exist in the group and $force parameter is set
588	* to false, then nothing will happen. The $force parameter is set to false
589	* by default.
590	*
591	* @param int\|string $key What the contents in the cache are called
592	* @param string $group Where the cache contents are grouped
593	* @param bool $force Optional. Whether to force the unsetting of the cache
594	* key in the group
595	* @return bool False if the contents weren't deleted and true on success
596	*/
597	public function delete( $key, $group = 'default', $force = false ) {
598
599	if ( empty( $group ) ) {
600	$group = 'default';
601	}
602
603	if ( ! $force && ! $this->_exists( $key, $group ) ) {
604	return false;
605	}
606
607	if ( $this->_should_persist( $group ) ) {
608	if ( $this->_should_use_redis_hashes( $group ) ) {
609	$redis_safe_group = $this->_key( '', $group );
610	$result = $this->_call_redis( 'hDel', $redis_safe_group, $key );
611	} else {
612	$id = $this->_key( $key, $group );
613	$result = $this->_call_redis( 'del', $id );
614	}
615	if ( 1 !== $result ) {
616	return false;
617	}
618	}
619
620	$this->_unset_internal( $key, $group );
621	return true;
622	}
623
624	/**
625	* Remove the contents of all cache keys in the group.
626	*
627	* @param string $group Where the cache contents are grouped.
628	* @return boolean True on success, false on failure.
629	*/
630	public function delete_group( $group ) {
631	if ( ! $this->_should_use_redis_hashes( $group ) ) {
632	return false;
633	}
634
635	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
636	$redis_safe_group = $this->_key( '', $group );
637	if ( $this->_should_persist( $group ) ) {
638	$result = $this->_call_redis( 'del', $redis_safe_group );
639	if ( 1 !== $result ) {
640	return false;
641	}
642	} elseif ( ! $this->_should_persist( $group ) && ! isset( $this->cache[ $multisite_safe_group ] ) ) {
643	return false;
644	}
645	unset( $this->cache[ $multisite_safe_group ] );
646	return true;
647	}
648
649	/**
650	* Clears the object cache of all data.
651	*
652	* By default, this will flush the session cache as well as Redis, but we
653	* can leave the redis cache intact if we want. This is helpful when, for
654	* instance, you're running a batch process and want to clear the session
655	* store to reduce the memory footprint, but you don't want to have to
656	* re-fetch all the values from the database.
657	*
658	* @param bool $redis Should we flush redis as well as the session cache?
659	* @return bool Always returns true
660	*/
661	public function flush( $redis = true ) {
662	$this->cache = array();
663	if ( $redis ) {
664	$this->_call_redis( 'flushdb' );
665	}
666
667	return true;
668	}
669
670	/**
671	* Retrieves the cache contents, if it exists
672	*
673	* The contents will be first attempted to be retrieved by searching by the
674	* key in the cache group. If the cache is hit (success) then the contents
675	* are returned.
676	*
677	* On failure, the number of cache misses will be incremented.
678	*
679	* @param int\|string $key What the contents in the cache are called
680	* @param string $group Where the cache contents are grouped
681	* @param string $force Whether to force a refetch rather than relying on the local cache (default is false)
682	* @param bool $found Optional. Whether the key was found in the cache. Disambiguates a return of false, a storable value. Passed by reference. Default null.
683	* @return bool\|mixed False on failure to retrieve contents or the cache contents on success
684	*/
685	public function get( $key, $group = 'default', $force = false, &$found = null ) {
686
687	if ( empty( $group ) ) {
688	$group = 'default';
689	}
690
691	// Key is set internally, so we can use this value
692	if ( $this->_isset_internal( $key, $group ) && ! $force ) {
693	$this->cache_hits += 1;
694	$found = true;
695	return $this->_get_internal( $key, $group );
696	}
697
698	// Not a persistent group, so don't try Redis if the value doesn't exist
699	// internally
700	if ( ! $this->_should_persist( $group ) ) {
701	$this->cache_misses += 1;
702	$found = false;
703	return false;
704	}
705
706	if ( $this->_should_use_redis_hashes( $group ) ) {
707	$redis_safe_group = $this->_key( '', $group );
708	$value = $this->_call_redis( 'hGet', $redis_safe_group, $key );
709	} else {
710	$id = $this->_key( $key, $group );
711	$value = $this->_call_redis( 'get', $id );
712	}
713
714	// PhpRedis returns `false` when the key doesn't exist
715	if ( false === $value ) {
716	$this->cache_misses += 1;
717	$found = false;
718	return false;
719	}
720
721	// All non-numeric values are serialized
722	$value = is_numeric( $value ) ? intval( $value ) : unserialize( $value );
723
724	$this->_set_internal( $key, $group, $value );
725	$this->cache_hits += 1;
726	$found = true;
727	return $value;
728	}
729
730	/**
731	* Retrieves multiple values from the cache in one call.
732	*
733	* @param array $keys Array of keys under which the cache contents are stored.
734	* @param string $group Optional. Where the cache contents are grouped. Default empty.
735	* @param bool $force Optional. Whether to force an update of the local cache
736	* from the persistent cache. Default false.
737	* @return array Array of values organized into groups.
738	*/
739	public function get_multiple( $keys, $group = 'default', $force = false ) {
740	if ( empty( $group ) ) {
741	$group = 'default';
742	}
743
744	$cache = array();
745	if ( ! $this->_should_persist( $group ) ) {
746	foreach ( $keys as $key ) {
747	$cache[ $key ] = $this->_isset_internal( $key, $group ) ? $this->_get_internal( $key, $group ) : false;
748	false !== $cache[ $key ] ? $this->cache_hits++ : $this->cache_misses++;
749	}
750	return $cache;
751	}
752
753	// Attempt to fetch values from the internal cache.
754	if ( ! $force ) {
755	foreach ( $keys as $key ) {
756	if ( $this->_isset_internal( $key, $group ) ) {
757	$cache[ $key ] = $this->_get_internal( $key, $group );
758	$this->cache_hits++;
759	}
760	}
761	}
762	$remaining_keys = array_values( array_diff( $keys, array_keys( $cache ) ) );
763	// If all keys were satisfied by the internal cache, we're sorted.
764	if ( empty( $remaining_keys ) ) {
765	return $cache;
766	}
767	if ( $this->_should_use_redis_hashes( $group ) ) {
768	$redis_safe_group = $this->_key( '', $group );
769	$results = $this->_call_redis( 'hmGet', $redis_safe_group, $remaining_keys );
770	$results = is_array( $results ) ? array_values( $results ) : $results;
771	} else {
772	$ids = array();
773	foreach ( $remaining_keys as $key ) {
774	$ids[] = $this->_key( $key, $group );
775	}
776	$results = $this->_call_redis( 'mget', $ids );
777	}
778	// Process the results from the Redis call.
779	foreach ( $remaining_keys as $i => $key ) {
780	$value = isset( $results[ $i ] ) ? $results[ $i ] : false;
781	if ( false !== $value ) {
782	// All non-numeric values are serialized
783	$value = is_numeric( $value ) ? intval( $value ) : unserialize( $value );
784	$this->_set_internal( $key, $group, $value );
785	$this->cache_hits++;
786	} else {
787	$this->cache_misses++;
788	}
789	$cache[ $key ] = $value;
790	}
791	// Make sure return values are returned in the order of the passed keys.
792	$return_cache = array();
793	foreach ( $keys as $key ) {
794	$return_cache[ $key ] = isset( $cache[ $key ] ) ? $cache[ $key ] : false;
795	}
796	return $return_cache;
797	}
798
799	/**
800	* Increment numeric cache item's value
801	*
802	* @param int\|string $key The cache key to increment
803	* @param int $offset The amount by which to increment the item's value. Default is 1.
804	* @param string $group The group the key is in.
805	* @return false\|int False on failure, the item's new value on success.
806	*/
807	public function incr( $key, $offset = 1, $group = 'default' ) {
808
809	if ( empty( $group ) ) {
810	$group = 'default';
811	}
812
813	// The key needs to exist in order to be incremented
814	if ( ! $this->_exists( $key, $group ) ) {
815	return false;
816	}
817
818	$offset = (int) $offset;
819
820	// If this isn't a persistent group, we have to sort this out ourselves, grumble grumble.
821	if ( ! $this->_should_persist( $group ) ) {
822	$existing = $this->_get_internal( $key, $group );
823	if ( empty( $existing ) \|\| ! is_numeric( $existing ) ) {
824	$existing = 1;
825	} else {
826	$existing += $offset;
827	}
828	if ( $existing < 0 ) {
829	$existing = 0;
830	}
831	$this->_set_internal( $key, $group, $existing );
832	return $existing;
833	}
834
835	if ( $this->_should_use_redis_hashes( $group ) ) {
836	$redis_safe_group = $this->_key( '', $group );
837	$result = $this->_call_redis( 'hIncrBy', $redis_safe_group, $key, $offset, $group );
838	if ( $result < 0 ) {
839	$result = 0;
840	$this->_call_redis( 'hSet', $redis_safe_group, $key, $result );
841	}
842	} else {
843	$id = $this->_key( $key, $group );
844	$result = $this->_call_redis( 'incrBy', $id, $offset );
845	if ( $result < 0 ) {
846	$result = 0;
847	$this->_call_redis( 'set', $id, $result );
848	}
849	}
850
851	if ( is_int( $result ) ) {
852	$this->_set_internal( $key, $group, $result );
853	}
854	return $result;
855	}
856
857	/**
858	* Replace the contents in the cache, if contents already exist
859	* @see WP_Object_Cache::set()
860	*
861	* @param int\|string $key What to call the contents in the cache
862	* @param mixed $data The contents to store in the cache
863	* @param string $group Where to group the cache contents
864	* @param int $expire When to expire the cache contents
865	* @return bool False if not exists, true if contents were replaced
866	*/
867	public function replace( $key, $data, $group = 'default', $expire = WP_REDIS_DEFAULT_EXPIRE_SECONDS ) {
868
869	if ( empty( $group ) ) {
870	$group = 'default';
871	}
872
873	if ( ! $this->_exists( $key, $group ) ) {
874	return false;
875	}
876
877	return $this->set( $key, $data, $group, (int) $expire );
878	}
879
880	/**
881	* Reset keys
882	*
883	* @deprecated 3.5.0
884	*/
885	public function reset() {
886	_deprecated_function( __FUNCTION__, '3.5', 'switch_to_blog()' );
887	}
888
889	/**
890	* Sets the data contents into the cache
891	*
892	* The cache contents is grouped by the $group parameter followed by the
893	* $key. This allows for duplicate ids in unique groups. Therefore, naming of
894	* the group should be used with care and should follow normal function
895	* naming guidelines outside of core WordPress usage.
896	*
897	* The $expire parameter is not used, because the cache will automatically
898	* expire for each time a page is accessed and PHP finishes. The method is
899	* more for cache plugins which use files.
900	*
901	* @param int\|string $key What to call the contents in the cache
902	* @param mixed $data The contents to store in the cache
903	* @param string $group Where to group the cache contents
904	* @param int $expire TTL for the data, in seconds
905	* @return bool Always returns true
906	*/
907	public function set( $key, $data, $group = 'default', $expire = WP_REDIS_DEFAULT_EXPIRE_SECONDS ) {
908
909	if ( empty( $group ) ) {
910	$group = 'default';
911	}
912
913	if ( is_object( $data ) ) {
914	$data = clone $data;
915	}
916
917	$this->_set_internal( $key, $group, $data );
918
919	if ( ! $this->_should_persist( $group ) ) {
920	return true;
921	}
922
923	// If this is an integer, store it as such. Otherwise, serialize it.
924	if ( ! is_numeric( $data ) \|\| intval( $data ) !== $data ) {
925	$data = serialize( $data );
926	}
927
928	// Redis doesn't support expire on hash group keys
929	if ( $this->_should_use_redis_hashes( $group ) ) {
930	$redis_safe_group = $this->_key( '', $group );
931	$this->_call_redis( 'hSet', $redis_safe_group, $key, $data );
932	return true;
933	}
934
935	$id = $this->_key( $key, $group );
936	if ( empty( $expire ) ) {
937	$this->_call_redis( 'set', $id, $data );
938	} else {
939	$this->_call_redis( 'setex', $id, $expire, $data );
940	}
941	return true;
942	}
943
944	/**
945	* Echoes the stats of the caching.
946	*
947	* Gives the cache hits, and cache misses. Also prints every cached group,
948	* key and the data.
949	*/
950	public function stats() {
951	$total_redis_calls = 0;
952	foreach ( $this->redis_calls as $method => $calls ) {
953	$total_redis_calls += $calls;
954	}
955	$out = array();
956	$out[] = '<p>';
957	$out[] = '<strong>Cache Hits:</strong>' . (int) $this->cache_hits . '<br />';
958	$out[] = '<strong>Cache Misses:</strong>' . (int) $this->cache_misses . '<br />';
959	$out[] = '<strong>Redis Client:</strong>' . get_class( $this->redis ) . '<br />';
960	$out[] = '<strong>Redis Calls:</strong>' . (int) $total_redis_calls . ':<br />';
961	foreach ( $this->redis_calls as $method => $calls ) {
962	$out[] = ' - ' . esc_html( $method ) . ': ' . (int) $calls . '<br />';
963	}
964	$out[] = '</p>';
965	$out[] = '<ul>';
966	foreach ( $this->cache as $group => $cache ) {
967	$out[] = '<li><strong>Group:</strong> ' . esc_html( $group ) . ' - ( ' . number_format( strlen( serialize( $cache ) ) / 1024, 2 ) . 'k )</li>';
968	}
969	$out[] = '</ul>';
970	echo implode( PHP_EOL, $out ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped,WordPressDotOrg.sniffs.OutputEscaping.UnescapedOutputParameter
971	}
972
973	/**
974	* Switch the internal blog id.
975	*
976	* This changes the blog id used to create keys in blog specific groups.
977	*
978	* @param int $blog_id Blog ID
979	*/
980	public function switch_to_blog( $blog_id ) {
981	$blog_id = (int) $blog_id;
982	$this->blog_prefix = $this->multisite ? $blog_id . ':' : '';
983	}
984
985	/**
986	* Utility function to determine whether a key exists in the cache.
987	*
988	* @access protected
989	*/
990	protected function _exists( $key, $group ) {
991	if ( $this->_isset_internal( $key, $group ) ) {
992	return true;
993	}
994
995	if ( ! $this->_should_persist( $group ) ) {
996	return false;
997	}
998
999	if ( $this->_should_use_redis_hashes( $group ) ) {
1000	$redis_safe_group = $this->_key( '', $group );
1001	return $this->_call_redis( 'hExists', $redis_safe_group, $key );
1002	}
1003	$id = $this->_key( $key, $group );
1004	return $this->_call_redis( 'exists', $id );
1005	}
1006
1007	/**
1008	* Check whether there's a value in the internal object cache.
1009	*
1010	* @param string $key
1011	* @param string $group
1012	* @return boolean
1013	*/
1014	protected function _isset_internal( $key, $group ) {
1015	if ( $this->_should_use_redis_hashes( $group ) ) {
1016	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
1017	return isset( $this->cache[ $multisite_safe_group ] ) && array_key_exists( $key, $this->cache[ $multisite_safe_group ] );
1018	} else {
1019	$key = $this->_key( $key, $group );
1020	return array_key_exists( $key, $this->cache );
1021	}
1022	}
1023
1024	/**
1025	* Get a value from the internal object cache
1026	*
1027	* @param string $key
1028	* @param string $group
1029	* @return mixed
1030	*/
1031	protected function _get_internal( $key, $group ) {
1032	$value = null;
1033	if ( $this->_should_use_redis_hashes( $group ) ) {
1034	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
1035	if ( isset( $this->cache[ $multisite_safe_group ] ) && array_key_exists( $key, $this->cache[ $multisite_safe_group ] ) ) {
1036	$value = $this->cache[ $multisite_safe_group ][ $key ];
1037	}
1038	} else {
1039	$key = $this->_key( $key, $group );
1040	if ( array_key_exists( $key, $this->cache ) ) {
1041	$value = $this->cache[ $key ];
1042	}
1043	}
1044	if ( is_object( $value ) ) {
1045	return clone $value;
1046	}
1047	return $value;
1048	}
1049
1050	/**
1051	* Set a value to the internal object cache
1052	*
1053	* @param string $key
1054	* @param string $group
1055	* @param mixed $value
1056	*/
1057	protected function _set_internal( $key, $group, $value ) {
1058	if ( $this->_should_use_redis_hashes( $group ) ) {
1059	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
1060	if ( ! isset( $this->cache[ $multisite_safe_group ] ) ) {
1061	$this->cache[ $multisite_safe_group ] = array();
1062	}
1063	$this->cache[ $multisite_safe_group ][ $key ] = $value;
1064	} else {
1065	$key = $this->_key( $key, $group );
1066	$this->cache[ $key ] = $value;
1067	}
1068	}
1069
1070	/**
1071	* Unset a value from the internal object cache
1072	*
1073	* @param string $key
1074	* @param string $group
1075	*/
1076	protected function _unset_internal( $key, $group ) {
1077	if ( $this->_should_use_redis_hashes( $group ) ) {
1078	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
1079	if ( isset( $this->cache[ $multisite_safe_group ] ) && array_key_exists( $key, $this->cache[ $multisite_safe_group ] ) ) {
1080	unset( $this->cache[ $multisite_safe_group ][ $key ] );
1081	}
1082	} else {
1083	$key = $this->_key( $key, $group );
1084	if ( array_key_exists( $key, $this->cache ) ) {
1085	unset( $this->cache[ $key ] );
1086	}
1087	}
1088	}
1089
1090	/**
1091	* Utility function to generate the redis key for a given key and group.
1092	*
1093	* @param string $key The cache key.
1094	* @param string $group The cache group.
1095	* @return string A properly prefixed redis cache key.
1096	*/
1097	protected function _key( $key = '', $group = 'default' ) {
1098	if ( empty( $group ) ) {
1099	$group = 'default';
1100	}
1101
1102	if ( ! empty( $this->global_groups[ $group ] ) ) {
1103	$prefix = $this->global_prefix;
1104	} else {
1105	$prefix = $this->blog_prefix;
1106	}
1107
1108	return preg_replace( '/\s+/', '', WP_CACHE_KEY_SALT . "$prefix$group:$key" );
1109	}
1110
1111	/**
1112	* Does this group use persistent storage?
1113	*
1114	* @param string $group Cache group.
1115	* @return bool true if the group is persistent, false if not.
1116	*/
1117	protected function _should_persist( $group ) {
1118	return empty( $this->non_persistent_groups[ $group ] );
1119	}
1120
1121	/**
1122	* Should this group use Redis hashes?
1123	*
1124	* @param string $group Cache group.
1125	* @return bool True if the group should use Redis hashes, false if not.
1126	*/
1127	protected function _should_use_redis_hashes( $group ) {
1128	if ( self::USE_GROUPS \|\| ! empty( $this->redis_hash_groups[ $group ] ) ) {
1129	return true;
1130	}
1131	return false;
1132	}
1133
1134	/**
1135	* Wrapper method for connecting to Redis, which lets us retry the connection
1136	*/
1137	protected function _connect_redis() {
1138	global $redis_server;
1139
1140	$check_dependencies = array( $this, 'check_client_dependencies' );
1141	/**
1142	* Permits alternate dependency check mechanism to be used.
1143	*
1144	* @param callable $check_dependencies Callback to execute.
1145	*/
1146	$check_dependencies = apply_filters( 'wp_redis_check_client_dependencies_callback', $check_dependencies );
1147	$dependencies_ok = call_user_func( $check_dependencies );
1148	if ( true !== $dependencies_ok ) {
1149	$this->is_redis_connected = false;
1150	$this->missing_redis_message = $dependencies_ok;
1151	return $this->is_redis_connected;
1152	}
1153	$client_parameters = $this->build_client_parameters( $redis_server );
1154
1155	try {
1156	$client_connection = array( $this, 'prepare_client_connection' );
1157	/**
1158	* Permits alternate initial client connection mechanism to be used.
1159	*
1160	* @param callable $client_connection Callback to execute.
1161	*/
1162	$client_connection = apply_filters( 'wp_redis_prepare_client_connection_callback', $client_connection );
1163	$this->redis = call_user_func_array( $client_connection, array( $client_parameters ) );
1164	} catch ( Exception $e ) {
1165	$this->_exception_handler( $e );
1166	$this->is_redis_connected = false;
1167	return $this->is_redis_connected;
1168	}
1169
1170	$keys_methods = array(
1171	'auth' => 'auth',
1172	'database' => 'select',
1173	);
1174
1175	try {
1176	$setup_connection = array( $this, 'perform_client_connection' );
1177	/**
1178	* Permits alternate setup client connection mechanism to be used.
1179	*
1180	* @param callable $setup_connection Callback to execute.
1181	*/
1182	$setup_connection = apply_filters( 'wp_redis_perform_client_connection_callback', $setup_connection );
1183	call_user_func_array( $setup_connection, array( $this->redis, $client_parameters, $keys_methods ) );
1184	} catch ( Exception $e ) {
1185	$this->_exception_handler( $e );
1186	$this->is_redis_connected = false;
1187	return $this->is_redis_connected;
1188	}
1189
1190	$this->is_redis_connected = $this->redis->isConnected();
1191	if ( ! $this->is_redis_connected ) {
1192	$this->missing_redis_message = 'Warning! WP Redis object cache cannot connect to Redis server.';
1193	}
1194	return $this->is_redis_connected;
1195	}
1196
1197	/**
1198	* Are the required dependencies for connecting to Redis available?
1199	*
1200	* @return mixed True if the required dependencies are present, string if
1201	* not with a message describing the issue.
1202	*/
1203	public function check_client_dependencies() {
1204	$class_to_check = 'Redis';
1205	if ( defined( 'WP_REDIS_USE_RELAY' ) && WP_REDIS_USE_RELAY ) {
1206	$class_to_check = 'Relay\Relay';
1207	}
1208
1209	if ( ! class_exists( $class_to_check ) ) {
1210	return 'Warning! PHPRedis extension is unavailable, which is required by WP Redis object cache.';
1211	}
1212
1213	return true;
1214	}
1215
1216	/**
1217	* Builds an array to be passed to a function that will set up the Redis
1218	* client.
1219	*
1220	* @param array $redis_server Parameters used to construct a Redis client.
1221	* @return array Final parameters to use to construct a Redis client with
1222	* with defaults applied.
1223	*/
1224	public function build_client_parameters( $redis_server ) {
1225	// Default Redis port.
1226	$port = 6379;
1227	// Default Redis database number.
1228	$database = 0;
1229
1230	if ( empty( $redis_server ) ) {
1231	// Attempt to automatically load Pantheon's Redis config from the env.
1232	if ( isset( $_SERVER['CACHE_HOST'] ) ) {
1233	$redis_server = [
1234	// Don't use WP methods to sanitize the host due to plugin loading issues with other caching methods.
1235	// @phpcs:ignore WordPressVIPMinimum.Functions.StripTags.StripTagsOneParameter,WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
1236	'host' => strip_tags( $_SERVER['CACHE_HOST'] ),
1237	'port' => ! empty( $_SERVER['CACHE_PORT'] ) ? intval( $_SERVER['CACHE_PORT'] ) : $port,
1238	// Don't attempt to sanitize passwords as this can break authentication.
1239	// @phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
1240	'auth' => ! empty( $_SERVER['CACHE_PASSWORD'] ) ? $_SERVER['CACHE_PASSWORD'] : null,
1241	'database' => ! empty( $_SERVER['CACHE_DB'] ) ? intval( $_SERVER['CACHE_DB'] ) : $database,
1242	];
1243	} else {
1244	$redis_server = [
1245	'host' => '127.0.0.1',
1246	'port' => $port,
1247	'database' => $database,
1248	];
1249	}
1250	}
1251
1252	if ( file_exists( $redis_server['host'] ) && 'socket' === filetype( $redis_server['host'] ) ) { // unix socket connection.
1253	// port must be null or socket won't connect.
1254	unset( $redis_server['port'] );
1255	$port = null;
1256	}
1257
1258	$defaults = [
1259	'host' => $redis_server['host'],
1260	'port' => $port,
1261	'timeout' => 1000, // I multiplied this by 1000 so we'd have a common measure of ms instead of s and ms, need to make sure this gets divided by 1000.
1262	'retry_interval' => 100,
1263	];
1264	// 1s timeout, 100ms delay between reconnections.
1265
1266	// merging the defaults with the original $redis_server enables any custom parameters to get sent downstream to the redis client.
1267	return array_replace_recursive( $defaults, $redis_server );
1268	}
1269
1270	/**
1271	* Constructs a PHPRedis Redis client.
1272	*
1273	* @param array $client_parameters Parameters used to construct a Redis client.
1274	* @return Redis Redis client.
1275	*/
1276	public function prepare_client_connection( $client_parameters ) {
1277	if ( defined( 'WP_REDIS_USE_RELAY' ) && WP_REDIS_USE_RELAY ) {
1278	$redis = new Relay\Relay;
1279	} else {
1280	$redis = new Redis;
1281	}
1282
1283	$redis->connect(
1284	$client_parameters['host'],
1285	$client_parameters['port'],
1286	// $client_parameters['timeout'] is sent in milliseconds,
1287	// connect() takes seconds, so divide by 1000
1288	$client_parameters['timeout'] / 1000,
1289	null,
1290	$client_parameters['retry_interval']
1291	);
1292
1293	return $redis;
1294	}
1295
1296	/**
1297	* Sets up the Redis connection (ie authentication and specific database).
1298	*
1299	* @param Redis $redis Redis client.
1300	* @param array $client_parameters Parameters used to configure Redis.
1301	* @param array $keys_methods Associative array of keys from
1302	* $client_parameters to use as method arguments for $redis.
1303	* @return bool True if successful.
1304	*/
1305	public function perform_client_connection( $redis, $client_parameters, $keys_methods ) {
1306	foreach ( $keys_methods as $key => $method ) {
1307	if ( ! isset( $client_parameters[ $key ] ) ) {
1308	continue;
1309	}
1310	try {
1311	$redis->$method( $client_parameters[ $key ] );
1312	} catch ( RedisException $e ) {
1313
1314	// PhpRedis throws an Exception when it fails a server call.
1315	// To prevent WordPress from fataling, we catch the Exception.
1316	throw new Exception( $e->getMessage(), $e->getCode(), $e );
1317	}
1318	}
1319	return true;
1320	}
1321
1322	/**
1323	* Wrapper method for calls to Redis, which fails gracefully when Redis is unavailable
1324	*
1325	* @param string $method
1326	* @param mixed $args
1327	* @return mixed
1328	*/
1329	protected function _call_redis( $method ) {
1330	global $wpdb;
1331
1332	$arguments = func_get_args();
1333	array_shift( $arguments ); // ignore $method
1334
1335	// $group is intended for the failback, and isn't passed to the Redis callback
1336	if ( 'hIncrBy' === $method ) {
1337	$group = array_pop( $arguments );
1338	}
1339
1340	if ( $this->is_redis_connected ) {
1341	try {
1342	if ( ! isset( $this->redis_calls[ $method ] ) ) {
1343	$this->redis_calls[ $method ] = 0;
1344	}
1345	$this->redis_calls[ $method ]++;
1346	$retval = call_user_func_array( array( $this->redis, $method ), $arguments );
1347	return $retval;
1348	} catch ( Exception $e ) {
1349	$retry_exception_messages = $this->retry_exception_messages();
1350	// PhpRedis throws an Exception when it fails a server call.
1351	// To prevent WordPress from fataling, we catch the Exception.
1352	if ( $this->exception_message_matches( $e->getMessage(), $retry_exception_messages ) ) {
1353
1354	$this->_exception_handler( $e );
1355
1356	// Attempt to refresh the connection if it was successfully established once
1357	// $this->is_redis_connected will be set inside _connect_redis()
1358	if ( $this->_connect_redis() ) {
1359	return call_user_func_array( array( $this, '_call_redis' ), array_merge( array( $method ), $arguments ) );
1360	}
1361	// Fall through to fallback below
1362	} else {
1363	throw $e;
1364	}
1365	}
1366	} // End if().
1367
1368	if ( $this->is_redis_failback_flush_enabled() && ! $this->do_redis_failback_flush && ! empty( $wpdb ) ) {
1369	if ( $this->multisite ) {
1370	$table = $wpdb->sitemeta;
1371	$col1 = 'meta_key';
1372	$col2 = 'meta_value';
1373	} else {
1374	$table = $wpdb->options;
1375	$col1 = 'option_name';
1376	$col2 = 'option_value';
1377	}
1378	// @codingStandardsIgnoreStart
1379	$wpdb->query( "INSERT IGNORE INTO {$table} ({$col1},{$col2}) VALUES ('wp_redis_do_redis_failback_flush',1)" );
1380	// @codingStandardsIgnoreEnd
1381	$this->do_redis_failback_flush = true;
1382	}
1383
1384	// Mock expected behavior from Redis for these methods
1385	switch ( $method ) {
1386	case 'incr':
1387	case 'incrBy':
1388	$val = $this->cache[ $arguments[0] ];
1389	$offset = isset( $arguments[1] ) && 'incrBy' === $method ? $arguments[1] : 1;
1390	$val = $val + $offset;
1391	return $val;
1392	case 'hIncrBy':
1393	$val = $this->_get_internal( $arguments[1], $group );
1394	return $val + $arguments[2];
1395	case 'decrBy':
1396	case 'decr':
1397	$val = $this->cache[ $arguments[0] ];
1398	$offset = isset( $arguments[1] ) && 'decrBy' === $method ? $arguments[1] : 1;
1399	$val = $val - $offset;
1400	return $val;
1401	case 'del':
1402	case 'hDel':
1403	return 1;
1404	case 'flushAll':
1405	case 'flushdb':
1406	case 'IsConnected':
1407	case 'exists':
1408	case 'get':
1409	case 'mget':
1410	case 'hGet':
1411	case 'hmGet':
1412	return false;
1413	}
1414
1415	}
1416
1417	/**
1418	* Returns a filterable array of expected Exception messages that may be thrown
1419	*
1420	* @return array Array of expected exception messages
1421	*/
1422	public function retry_exception_messages() {
1423	$retry_exception_messages = array( 'socket error on read socket', 'Connection closed', 'Redis server went away' );
1424	return apply_filters( 'wp_redis_retry_exception_messages', $retry_exception_messages );
1425	}
1426
1427	/**
1428	* Compares individual message to list of messages.
1429	*
1430	* @param string $error Message to compare
1431	* @param array $errors Array of messages to compare to
1432	* @return bool whether $error matches any items in $errors
1433	*/
1434	public function exception_message_matches( $error, $errors ) {
1435	foreach ( $errors as $message ) {
1436	$pattern = $this->_format_message_for_pattern( $message );
1437	$matches = (bool) preg_match( $pattern, $error );
1438	if ( $matches ) {
1439	return true;
1440	}
1441	}
1442	return false;
1443	}
1444
1445	/**
1446	* Prepends and appends '/' if not present in a string
1447	*
1448	* @param string $message Potential regex string that may need '/'
1449	* @return string Regex pattern
1450	*/
1451	protected function _format_message_for_pattern( $message ) {
1452	$var = $message;
1453	$var = '/' === $var[0] ? $var : '/' . $var;
1454	$var = '/' === $var[ strlen( $var ) - 1 ] ? $var : $var . '/';
1455	return $var;
1456	}
1457
1458	/**
1459	* Handles exceptions by triggering a php error.
1460	*
1461	* @param Exception $exception
1462	* @return null
1463	*/
1464	protected function _exception_handler( $exception ) {
1465	try {
1466	$this->last_triggered_error = 'WP Redis: ' . $exception->getMessage();
1467	// pc:fix
1468	$this->missing_redis_message = 'Redis Connection error, please check the credentials!';
1469	// Be friendly to developers debugging production servers by triggering an error
1470	// @codingStandardsIgnoreStart
1471	trigger_error( $this->last_triggered_error, E_USER_WARNING );
1472	// @codingStandardsIgnoreEnd
1473	} catch ( PHPUnit_Framework_Error_Warning $e ) {
1474	// PHPUnit throws an Exception when `trigger_error()` is called.
1475	// To ensure our tests (which expect Exceptions to be caught) continue to run,
1476	// we catch the PHPUnit exception and inspect the RedisException message
1477	}
1478	}
1479
1480	/**
1481	* Admin UI to let the end user know something about the Redis connection isn't working.
1482	*/
1483	public function wp_action_admin_notices_warn_missing_redis() {
1484	if ( ! current_user_can( 'manage_options' ) \|\| empty( $this->missing_redis_message ) ) {
1485	return;
1486	}
1487	echo '<div class="message error"><p>' . esc_html( $this->missing_redis_message ) . '</p></div>';
1488	}
1489
1490	/**
1491	* Whether or not wakeup flush is enabled
1492	*
1493	* @return bool
1494	*/
1495	private function is_redis_failback_flush_enabled() {
1496	if ( defined( 'WP_INSTALLING' ) && WP_INSTALLING ) {
1497	return false;
1498	} elseif ( defined( 'WP_REDIS_DISABLE_FAILBACK_FLUSH' ) && WP_REDIS_DISABLE_FAILBACK_FLUSH ) {
1499	return false;
1500	}
1501	return true;
1502	}
1503
1504	/**
1505	* Sets up object properties; PHP 5 style constructor
1506	*
1507	* @return null\|WP_Object_Cache If cache is disabled, returns null.
1508	*/
1509	public function __construct() {
1510	global $blog_id, $table_prefix, $wpdb;
1511
1512	$this->multisite = is_multisite();
1513	$this->blog_prefix = $this->multisite ? $blog_id . ':' : '';
1514
1515	if ( ! $this->_connect_redis() && function_exists( 'add_action' ) ) {
1516	add_action( 'admin_notices', array( $this, 'wp_action_admin_notices_warn_missing_redis' ) );
1517	}
1518
1519	if ( $this->is_redis_failback_flush_enabled() && ! empty( $wpdb ) ) {
1520	if ( $this->multisite ) {
1521	$table = $wpdb->sitemeta;
1522	$col1 = 'meta_key';
1523	$col2 = 'meta_value';
1524	} else {
1525	$table = $wpdb->options;
1526	$col1 = 'option_name';
1527	$col2 = 'option_value';
1528	}
1529	// @codingStandardsIgnoreStart
1530	$this->do_redis_failback_flush = (bool) $wpdb->get_results( "SELECT {$col2} FROM {$table} WHERE {$col1}='wp_redis_do_redis_failback_flush'" );
1531	// @codingStandardsIgnoreEnd
1532	if ( $this->is_redis_connected && $this->do_redis_failback_flush ) {
1533	$ret = $this->_call_redis( 'flushdb' );
1534	if ( $ret ) {
1535	// @codingStandardsIgnoreStart
1536	$wpdb->query( "DELETE FROM {$table} WHERE {$col1}='wp_redis_do_redis_failback_flush'" );
1537	// @codingStandardsIgnoreEnd
1538	$this->do_redis_failback_flush = false;
1539	}
1540	}
1541	}
1542
1543	$this->global_prefix = ( $this->multisite \|\| defined( 'CUSTOM_USER_TABLE' ) && defined( 'CUSTOM_USER_META_TABLE' ) ) ? '' : $table_prefix;
1544
1545	/**
1546	* @todo This should be moved to the PHP4 style constructor, PHP5
1547	* already calls __destruct()
1548	*/
1549	register_shutdown_function( array( $this, '__destruct' ) );
1550	}
1551
1552	/**
1553	* Will save the object cache before object is completely destroyed.
1554	*
1555	* Called upon object destruction, which should be when PHP ends.
1556	*
1557	* @return bool True value. Won't be used by PHP
1558	*/
1559	public function __destruct() {
1560	return true;
1561	}
1562	}
1563