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 1.1, 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	/**
21	* Adds data to the cache, if the cache key doesn't already exist.
22	*
23	* @uses $wp_object_cache Object Cache Class
24	* @see WP_Object_Cache::add()
25	*
26	* @param int\|string $key The cache key to use for retrieval later
27	* @param mixed $data The data to add to the cache store
28	* @param string $group The group to add the cache to
29	* @param int $expire When the cache data should be expired
30	* @return bool False if cache key and group already exist, true on success
31	*/
32	function wp_cache_add( $key, $data, $group = '', $expire = 0 ) {
33	global $wp_object_cache;
34
35	return $wp_object_cache->add( $key, $data, $group, (int) $expire );
36	}
37
38	/**
39	* Closes the cache.
40	*
41	* This function has ceased to do anything since WordPress 2.5. The
42	* functionality was removed along with the rest of the persistent cache. This
43	* does not mean that plugins can't implement this function when they need to
44	* make sure that the cache is cleaned up after WordPress no longer needs it.
45	*
46	* @return bool Always returns True
47	*/
48	function wp_cache_close() {
49	return true;
50	}
51
52	/**
53	* Decrement numeric cache item's value
54	*
55	* @uses $wp_object_cache Object Cache Class
56	* @see WP_Object_Cache::decr()
57	*
58	* @param int\|string $key The cache key to increment
59	* @param int $offset The amount by which to decrement the item's value. Default is 1.
60	* @param string $group The group the key is in.
61	* @return false\|int False on failure, the item's new value on success.
62	*/
63	function wp_cache_decr( $key, $offset = 1, $group = '' ) {
64	global $wp_object_cache;
65
66	return $wp_object_cache->decr( $key, $offset, $group );
67	}
68
69	/**
70	* Removes the cache contents matching key and group.
71	*
72	* @uses $wp_object_cache Object Cache Class
73	* @see WP_Object_Cache::delete()
74	*
75	* @param int\|string $key What the contents in the cache are called
76	* @param string $group Where the cache contents are grouped
77	* @return bool True on successful removal, false on failure
78	*/
79	function wp_cache_delete( $key, $group = '' ) {
80	global $wp_object_cache;
81
82	return $wp_object_cache->delete( $key, $group );
83	}
84
85	/**
86	* Removes cache contents for a given group.
87	*
88	* @uses $wp_object_cache Object Cache Class
89	* @see WP_Object_Cache::delete_group()
90	*
91	* @param string $group Where the cache contents are grouped
92	* @return bool True on successful removal, false on failure
93	*/
94	function wp_cache_delete_group( $group ) {
95	global $wp_object_cache;
96	return $wp_object_cache->delete_group( $group );
97	}
98
99
100	/**
101	* Removes all cache items.
102	*
103	* @uses $wp_object_cache Object Cache Class
104	* @see WP_Object_Cache::flush()
105	*
106	* @return bool False on failure, true on success
107	*/
108	function wp_cache_flush() {
109	global $wp_object_cache;
110
111	return $wp_object_cache->flush();
112	}
113
114	/**
115	* Retrieves the cache contents from the cache by key and group.
116	*
117	* @uses $wp_object_cache Object Cache Class
118	* @see WP_Object_Cache::get()
119	*
120	* @param int\|string $key What the contents in the cache are called
121	* @param string $group Where the cache contents are grouped
122	* @param bool $force Whether to force an update of the local cache from the persistent cache (default is false)
123	* @param &bool $found Whether key was found in the cache. Disambiguates a return of false, a storable value.
124	* @return bool\|mixed False on failure to retrieve contents or the cache
125	* contents on success
126	*/
127	function wp_cache_get( $key, $group = '', $force = false, &$found = null ) {
128	global $wp_object_cache;
129
130	return $wp_object_cache->get( $key, $group, $force, $found );
131	}
132
133	/**
134	* Increment numeric cache item's value
135	*
136	* @uses $wp_object_cache Object Cache Class
137	* @see WP_Object_Cache::incr()
138	*
139	* @param int\|string $key The cache key to increment
140	* @param int $offset The amount by which to increment the item's value. Default is 1.
141	* @param string $group The group the key is in.
142	* @return false\|int False on failure, the item's new value on success.
143	*/
144	function wp_cache_incr( $key, $offset = 1, $group = '' ) {
145	global $wp_object_cache;
146
147	return $wp_object_cache->incr( $key, $offset, $group );
148	}
149
150	/**
151	* Sets up Object Cache Global and assigns it.
152	*
153	* @global WP_Object_Cache $wp_object_cache WordPress Object Cache
154	*/
155	function wp_cache_init() {
156	$GLOBALS['wp_object_cache'] = new WP_Object_Cache();
157	}
158
159	/**
160	* Replaces the contents of the cache with new data.
161	*
162	* @uses $wp_object_cache Object Cache Class
163	* @see WP_Object_Cache::replace()
164	*
165	* @param int\|string $key What to call the contents in the cache
166	* @param mixed $data The contents to store in the cache
167	* @param string $group Where to group the cache contents
168	* @param int $expire When to expire the cache contents
169	* @return bool False if not exists, true if contents were replaced
170	*/
171	function wp_cache_replace( $key, $data, $group = '', $expire = 0 ) {
172	global $wp_object_cache;
173
174	return $wp_object_cache->replace( $key, $data, $group, (int) $expire );
175	}
176
177	/**
178	* Saves the data to the cache.
179	*
180	* @uses $wp_object_cache Object Cache Class
181	* @see WP_Object_Cache::set()
182	*
183	* @param int\|string $key What to call the contents in the cache
184	* @param mixed $data The contents to store in the cache
185	* @param string $group Where to group the cache contents
186	* @param int $expire When to expire the cache contents
187	* @return bool False on failure, true on success
188	*/
189	function wp_cache_set( $key, $data, $group = '', $expire = 0 ) {
190	global $wp_object_cache;
191
192	return $wp_object_cache->set( $key, $data, $group, (int) $expire );
193	}
194
195	/**
196	* Switch the interal blog id.
197	*
198	* This changes the blog id used to create keys in blog specific groups.
199	*
200	* @param int $blog_id Blog ID
201	*/
202	function wp_cache_switch_to_blog( $blog_id ) {
203	global $wp_object_cache;
204
205	return $wp_object_cache->switch_to_blog( $blog_id );
206	}
207
208	/**
209	* Adds a group or set of groups to the list of global groups.
210	*
211	* @param string\|array $groups A group or an array of groups to add
212	*/
213	function wp_cache_add_global_groups( $groups ) {
214	global $wp_object_cache;
215
216	return $wp_object_cache->add_global_groups( $groups );
217	}
218
219	/**
220	* Adds a group or set of groups to the list of non-persistent groups.
221	*
222	* @param string\|array $groups A group or an array of groups to add
223	*/
224	function wp_cache_add_non_persistent_groups( $groups ) {
225	global $wp_object_cache;
226
227	$wp_object_cache->add_non_persistent_groups( $groups );
228	}
229
230	/**
231	* Adds a group or set of groups to the list of groups that use Redis hashes.
232	*
233	* @param string\|array $groups A group or an array of groups to add.
234	*/
235	function wp_cache_add_redis_hash_groups( $groups ) {
236	global $wp_object_cache;
237
238	$wp_object_cache->add_redis_hash_groups( $groups );
239	}
240
241	/**
242	* Reset internal cache keys and structures. If the cache backend uses global
243	* blog or site IDs as part of its cache keys, this function instructs the
244	* backend to reset those keys and perform any cleanup since blog or site IDs
245	* have changed since cache init.
246	*
247	* This function is deprecated. Use wp_cache_switch_to_blog() instead of this
248	* function when preparing the cache for a blog switch. For clearing the cache
249	* during unit tests, consider using wp_cache_init(). wp_cache_init() is not
250	* recommended outside of unit tests as the performance penality for using it is
251	* high.
252	*
253	* @deprecated 3.5.0
254	*/
255	function wp_cache_reset() {
256	_deprecated_function( __FUNCTION__, '3.5' );
257
258	global $wp_object_cache;
259
260	return $wp_object_cache->reset();
261	}
262
263	/**
264	* WordPress Object Cache
265	*
266	* The WordPress Object Cache is used to save on trips to the database. The
267	* Object Cache stores all of the cache data to memory and makes the cache
268	* contents available by using a key, which is used to name and later retrieve
269	* the cache contents.
270	*
271	* The Object Cache can be replaced by other caching mechanisms by placing files
272	* in the wp-content folder which is looked at in wp-settings. If that file
273	* exists, then this file will not be included.
274	*/
275	class WP_Object_Cache {
276
277	/**
278	* Holds the cached objects
279	*
280	* @var array
281	* @access private
282	*/
283	var $cache = array();
284
285	/**
286	* The amount of times the cache data was already stored in the cache.
287	*
288	* @access private
289	* @var int
290	*/
291	var $cache_hits = 0;
292
293	/**
294	* Amount of times the cache did not have the request in cache
295	*
296	* @var int
297	* @access public
298	*/
299	var $cache_misses = 0;
300
301	/**
302	* The amount of times a request was made to Redis
303	*
304	* @access private
305	* @var int
306	*/
307	var $redis_calls = array();
308
309	/**
310	* List of global groups
311	*
312	* @var array
313	* @access protected
314	*/
315	var $global_groups = array();
316
317	/**
318	* List of non-persistent groups
319	*
320	* @var array
321	* @access protected
322	*/
323	var $non_persistent_groups = array();
324
325	/**
326	* List of groups which use Redis hashes.
327	*
328	* @var array
329	* @access protected
330	*/
331	var $redis_hash_groups = array();
332
333	/**
334	* The blog prefix to prepend to keys in non-global groups.
335	*
336	* @var int
337	* @access private
338	*/
339	var $blog_prefix;
340
341	/**
342	* Whether or not Redis is connected
343	*
344	* @var bool
345	* @access private
346	*/
347	var $is_redis_connected = false;
348
349	/**
350	* Whether or not the object cache thinks Redis needs a flush
351	*
352	* @var bool
353	* @access private
354	*/
355	var $do_redis_failback_flush = false;
356
357	/**
358	* The last triggered error
359	*/
360	var $last_triggered_error = '';
361
362	/**
363	* Whether or not to use true cache groups, instead of flattening.
364	*
365	* @var bool
366	* @access private
367	*/
368	const USE_GROUPS = WP_REDIS_USE_CACHE_GROUPS;
369
370	/**
371	* Adds data to the cache if it doesn't already exist.
372	*
373	* @uses WP_Object_Cache::_exists Checks to see if the cache already has data.
374	* @uses WP_Object_Cache::set Sets the data after the checking the cache
375	* contents existence.
376	*
377	* @param int\|string $key What to call the contents in the cache
378	* @param mixed $data The contents to store in the cache
379	* @param string $group Where to group the cache contents
380	* @param int $expire When to expire the cache contents
381	* @return bool False if cache key and group already exist, true on success
382	*/
383	public function add( $key, $data, $group = 'default', $expire = 0 ) {
384
385	if ( empty( $group ) ) {
386	$group = 'default';
387	}
388
389	if ( function_exists( 'wp_suspend_cache_addition' ) && wp_suspend_cache_addition() ) {
390	return false;
391	}
392
393	if ( $this->_exists( $key, $group ) ) {
394	return false;
395	}
396
397	return $this->set( $key, $data, $group, (int) $expire );
398	}
399
400	/**
401	* Sets the list of global groups.
402	*
403	* @param array $groups List of groups that are global.
404	*/
405	public function add_global_groups( $groups ) {
406	$groups = (array) $groups;
407
408	$groups = array_fill_keys( $groups, true );
409	$this->global_groups = array_merge( $this->global_groups, $groups );
410	}
411
412	/**
413	* Sets the list of non-persistent groups.
414	*
415	* @param array $groups List of groups that are non-persistent.
416	*/
417	public function add_non_persistent_groups( $groups ) {
418	$groups = (array) $groups;
419
420	$groups = array_fill_keys( $groups, true );
421	$this->non_persistent_groups = array_merge( $this->non_persistent_groups, $groups );
422	}
423
424	/**
425	* Sets the list of groups that use Redis hashes.
426	*
427	* @param array $groups List of groups that use Redis hashes.
428	*/
429	public function add_redis_hash_groups( $groups ) {
430	$groups = (array) $groups;
431
432	$groups = array_fill_keys( $groups, true );
433	$this->redis_hash_groups = array_merge( $this->redis_hash_groups, $groups );
434	}
435
436	/**
437	* Decrement numeric cache item's value
438	*
439	* @param int\|string $key The cache key to increment
440	* @param int $offset The amount by which to decrement the item's value. Default is 1.
441	* @param string $group The group the key is in.
442	* @return false\|int False on failure, the item's new value on success.
443	*/
444	public function decr( $key, $offset = 1, $group = 'default' ) {
445
446	if ( empty( $group ) ) {
447	$group = 'default';
448	}
449
450	// The key needs to exist in order to be decremented
451	if ( ! $this->_exists( $key, $group ) ) {
452	return false;
453	}
454
455	$offset = (int) $offset;
456
457	# If this isn't a persistant group, we have to sort this out ourselves, grumble grumble
458	if ( ! $this->_should_persist( $group ) ) {
459	$existing = $this->_get_internal( $key, $group );
460	if ( empty( $existing ) \|\| ! is_numeric( $existing ) ) {
461	$existing = 0;
462	} else {
463	$existing -= $offset;
464	}
465	if ( $existing < 0 ) {
466	$existing = 0;
467	}
468	$this->_set_internal( $key, $group, $existing );
469	return $existing;
470	}
471
472	if ( $this->_should_use_redis_hashes( $group ) ) {
473	$redis_safe_group = $this->_key( '', $group );
474	$result = $this->_call_redis( 'hIncrBy', $redis_safe_group, $key, -$offset, $group );
475	if ( $result < 0 ) {
476	$result = 0;
477	$this->_call_redis( 'hSet', $redis_safe_group, $key, $result );
478	}
479	} else {
480	$id = $this->_key( $key, $group );
481	$result = $this->_call_redis( 'decrBy', $id, $offset );
482	if ( $result < 0 ) {
483	$result = 0;
484	$this->_call_redis( 'set', $id, $result );
485	}
486	}
487
488	if ( is_int( $result ) ) {
489	$this->_set_internal( $key, $group, $result );
490	}
491	return $result;
492	}
493
494	/**
495	* Remove the contents of the cache key in the group
496	*
497	* If the cache key does not exist in the group and $force parameter is set
498	* to false, then nothing will happen. The $force parameter is set to false
499	* by default.
500	*
501	* @param int\|string $key What the contents in the cache are called
502	* @param string $group Where the cache contents are grouped
503	* @param bool $force Optional. Whether to force the unsetting of the cache
504	* key in the group
505	* @return bool False if the contents weren't deleted and true on success
506	*/
507	public function delete( $key, $group = 'default', $force = false ) {
508
509	if ( empty( $group ) ) {
510	$group = 'default';
511	}
512
513	if ( ! $force && ! $this->_exists( $key, $group ) ) {
514	return false;
515	}
516
517	if ( $this->_should_persist( $group ) ) {
518	if ( $this->_should_use_redis_hashes( $group ) ) {
519	$redis_safe_group = $this->_key( '', $group );
520	$result = $this->_call_redis( 'hDel', $redis_safe_group, $key );
521	} else {
522	$id = $this->_key( $key, $group );
523	$result = $this->_call_redis( 'del', $id );
524	}
525	if ( 1 !== $result ) {
526	return false;
527	}
528	}
529
530	$this->_unset_internal( $key, $group );
531	return true;
532	}
533
534	/**
535	* Remove the contents of all cache keys in the group.
536	*
537	* @param string $group Where the cache contents are grouped.
538	* @return boolean True on success, false on failure.
539	*/
540	public function delete_group( $group ) {
541	if ( ! $this->_should_use_redis_hashes( $group ) ) {
542	return false;
543	}
544
545	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
546	$redis_safe_group = $this->_key( '', $group );
547	if ( $this->_should_persist( $group ) ) {
548	$result = $this->_call_redis( 'del', $redis_safe_group );
549	if ( 1 !== $result ) {
550	return false;
551	}
552	} elseif ( ! $this->_should_persist( $group ) && ! isset( $this->cache[ $multisite_safe_group ] ) ) {
553	return false;
554	}
555	unset( $this->cache[ $multisite_safe_group ] );
556	return true;
557	}
558
559	/**
560	* Clears the object cache of all data.
561	*
562	* By default, this will flush the session cache as well as Redis, but we
563	* can leave the redis cache intact if we want. This is helpful when, for
564	* instance, you're running a batch process and want to clear the session
565	* store to reduce the memory footprint, but you don't want to have to
566	* re-fetch all the values from the database.
567	*
568	* @param bool $redis Should we flush redis as well as the session cache?
569	* @return bool Always returns true
570	*/
571	public function flush( $redis = true ) {
572	$this->cache = array();
573	if ( $redis ) {
574	$this->_call_redis( 'flushAll' );
575	}
576
577	return true;
578	}
579
580	/**
581	* Retrieves the cache contents, if it exists
582	*
583	* The contents will be first attempted to be retrieved by searching by the
584	* key in the cache group. If the cache is hit (success) then the contents
585	* are returned.
586	*
587	* On failure, the number of cache misses will be incremented.
588	*
589	* @param int\|string $key What the contents in the cache are called
590	* @param string $group Where the cache contents are grouped
591	* @param string $force Whether to force a refetch rather than relying on the local cache (default is false)
592	* @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.
593	* @return bool\|mixed False on failure to retrieve contents or the cache
594	* contents on success
595	*/
596	public function get( $key, $group = 'default', $force = false, &$found = null ) {
597
598	if ( empty( $group ) ) {
599	$group = 'default';
600	}
601
602	// Key is set internally, so we can use this value
603	if ( $this->_isset_internal( $key, $group ) && ! $force ) {
604	$this->cache_hits += 1;
605	$found = true;
606	return $this->_get_internal( $key, $group );
607	}
608
609	// Not a persistent group, so don't try Redis if the value doesn't exist
610	// internally
611	if ( ! $this->_should_persist( $group ) ) {
612	$this->cache_misses += 1;
613	$found = false;
614	return false;
615	}
616
617	if ( $this->_should_use_redis_hashes( $group ) ) {
618	$redis_safe_group = $this->_key( '', $group );
619	$value = $this->_call_redis( 'hGet', $redis_safe_group, $key );
620	} else {
621	$id = $this->_key( $key, $group );
622	$value = $this->_call_redis( 'get', $id );
623	}
624
625	// PhpRedis returns `false` when the key doesn't exist
626	if ( false === $value ) {
627	$this->cache_misses += 1;
628	$found = false;
629	return false;
630	}
631
632	// All non-numeric values are serialized
633	if ( ! is_numeric( $value ) ) {
634	$value = unserialize( $value );
635	}
636
637	$this->_set_internal( $key, $group, $value );
638	$this->cache_hits += 1;
639	$found = true;
640	return $value;
641	}
642
643	/**
644	* Increment numeric cache item's value
645	*
646	* @param int\|string $key The cache key to increment
647	* @param int $offset The amount by which to increment the item's value. Default is 1.
648	* @param string $group The group the key is in.
649	* @return false\|int False on failure, the item's new value on success.
650	*/
651	public function incr( $key, $offset = 1, $group = 'default' ) {
652
653	if ( empty( $group ) ) {
654	$group = 'default';
655	}
656
657	// The key needs to exist in order to be incremented
658	if ( ! $this->_exists( $key, $group ) ) {
659	return false;
660	}
661
662	$offset = (int) $offset;
663
664	# If this isn't a persistant group, we have to sort this out ourselves, grumble grumble
665	if ( ! $this->_should_persist( $group ) ) {
666	$existing = $this->_get_internal( $key, $group );
667	if ( empty( $existing ) \|\| ! is_numeric( $existing ) ) {
668	$existing = 1;
669	} else {
670	$existing += $offset;
671	}
672	if ( $existing < 0 ) {
673	$existing = 0;
674	}
675	$this->_set_internal( $key, $group, $existing );
676	return $existing;
677	}
678
679	if ( $this->_should_use_redis_hashes( $group ) ) {
680	$redis_safe_group = $this->_key( '', $group );
681	$result = $this->_call_redis( 'hIncrBy', $redis_safe_group, $key, $offset, $group );
682	if ( $result < 0 ) {
683	$result = 0;
684	$this->_call_redis( 'hSet', $redis_safe_group, $key, $result );
685	}
686	} else {
687	$id = $this->_key( $key, $group );
688	$result = $this->_call_redis( 'incrBy', $id, $offset );
689	if ( $result < 0 ) {
690	$result = 0;
691	$this->_call_redis( 'set', $id, $result );
692	}
693	}
694
695	if ( is_int( $result ) ) {
696	$this->_set_internal( $key, $group, $result );
697	}
698	return $result;
699	}
700
701	/**
702	* Replace the contents in the cache, if contents already exist
703	* @see WP_Object_Cache::set()
704	*
705	* @param int\|string $key What to call the contents in the cache
706	* @param mixed $data The contents to store in the cache
707	* @param string $group Where to group the cache contents
708	* @param int $expire When to expire the cache contents
709	* @return bool False if not exists, true if contents were replaced
710	*/
711	public function replace( $key, $data, $group = 'default', $expire = 0 ) {
712
713	if ( empty( $group ) ) {
714	$group = 'default';
715	}
716
717	if ( ! $this->_exists( $key, $group ) ) {
718	return false;
719	}
720
721	return $this->set( $key, $data, $group, (int) $expire );
722	}
723
724	/**
725	* Reset keys
726	*
727	* @deprecated 3.5.0
728	*/
729	public function reset() {
730	_deprecated_function( __FUNCTION__, '3.5', 'switch_to_blog()' );
731	}
732
733	/**
734	* Sets the data contents into the cache
735	*
736	* The cache contents is grouped by the $group parameter followed by the
737	* $key. This allows for duplicate ids in unique groups. Therefore, naming of
738	* the group should be used with care and should follow normal function
739	* naming guidelines outside of core WordPress usage.
740	*
741	* The $expire parameter is not used, because the cache will automatically
742	* expire for each time a page is accessed and PHP finishes. The method is
743	* more for cache plugins which use files.
744	*
745	* @param int\|string $key What to call the contents in the cache
746	* @param mixed $data The contents to store in the cache
747	* @param string $group Where to group the cache contents
748	* @param int $expire TTL for the data, in seconds
749	* @return bool Always returns true
750	*/
751	public function set( $key, $data, $group = 'default', $expire = 0 ) {
752
753	if ( empty( $group ) ) {
754	$group = 'default';
755	}
756
757	if ( is_object( $data ) ) {
758	$data = clone $data;
759	}
760
761	$this->_set_internal( $key, $group, $data );
762
763	if ( ! $this->_should_persist( $group ) ) {
764	return true;
765	}
766
767	# If this is an integer, store it as such. Otherwise, serialize it.
768	if ( ! is_numeric( $data ) \|\| intval( $data ) !== $data ) {
769	$data = serialize( $data );
770	}
771
772	// Redis doesn't support expire on hash group keys
773	if ( $this->_should_use_redis_hashes( $group ) ) {
774	$redis_safe_group = $this->_key( '', $group );
775	$this->_call_redis( 'hSet', $redis_safe_group, $key, $data );
776	return true;
777	}
778
779	$id = $this->_key( $key, $group );
780	if ( empty( $expire ) ) {
781	$this->_call_redis( 'set', $id, $data );
782	} else {
783	$this->_call_redis( 'setex', $id, $expire, $data );
784	}
785	return true;
786	}
787
788	/**
789	* Echoes the stats of the caching.
790	*
791	* Gives the cache hits, and cache misses. Also prints every cached group,
792	* key and the data.
793	*/
794	public function stats() {
795	$total_redis_calls = 0;
796	foreach ( $this->redis_calls as $method => $calls ) {
797	$total_redis_calls += $calls;
798	}
799	$out = array();
800	$out[] = '<p>';
801	$out[] = '<strong>Cache Hits:</strong>' . (int) $this->cache_hits . '<br />';
802	$out[] = '<strong>Cache Misses:</strong>' . (int) $this->cache_misses . '<br />';
803	$out[] = '<strong>Redis Calls:</strong>' . (int) $total_redis_calls . ':<br />';
804	foreach ( $this->redis_calls as $method => $calls ) {
805	$out[] = ' - ' . esc_html( $method ) . ': ' . (int) $calls . '<br />';
806	}
807	$out[] = '</p>';
808	$out[] = '<ul>';
809	foreach ( $this->cache as $group => $cache ) {
810	$out[] = '<li><strong>Group:</strong> ' . esc_html( $group ) . ' - ( ' . number_format( strlen( serialize( $cache ) ) / 1024, 2 ) . 'k )</li>';
811	}
812	$out[] = '</ul>';
813	// @codingStandardsIgnoreStart
814	echo implode( PHP_EOL, $out );
815	// @codingStandardsIgnoreEnd
816	}
817
818	/**
819	* Switch the interal blog id.
820	*
821	* This changes the blog id used to create keys in blog specific groups.
822	*
823	* @param int $blog_id Blog ID
824	*/
825	public function switch_to_blog( $blog_id ) {
826	$blog_id = (int) $blog_id;
827	$this->blog_prefix = $this->multisite ? $blog_id . ':' : '';
828	}
829
830	/**
831	* Utility function to determine whether a key exists in the cache.
832	*
833	* @access protected
834	*/
835	protected function _exists( $key, $group ) {
836	if ( $this->_isset_internal( $key, $group ) ) {
837	return true;
838	}
839
840	if ( ! $this->_should_persist( $group ) ) {
841	return false;
842	}
843
844	if ( $this->_should_use_redis_hashes( $group ) ) {
845	$redis_safe_group = $this->_key( '', $group );
846	return $this->_call_redis( 'hExists', $redis_safe_group, $key );
847	}
848	$id = $this->_key( $key, $group );
849	return $this->_call_redis( 'exists', $id );
850	}
851
852	/**
853	* Check whether there's a value in the internal object cache.
854	*
855	* @param string $key
856	* @param string $group
857	* @return boolean
858	*/
859	protected function _isset_internal( $key, $group ) {
860	if ( $this->_should_use_redis_hashes( $group ) ) {
861	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
862	return isset( $this->cache[ $multisite_safe_group ][ $key ] );
863	} else {
864	$key = $this->_key( $key, $group );
865	return isset( $this->cache[ $key ] );
866	}
867	}
868
869	/**
870	* Get a value from the internal object cache
871	*
872	* @param string $key
873	* @param string $group
874	* @return mixed
875	*/
876	protected function _get_internal( $key, $group ) {
877	$value = null;
878	if ( $this->_should_use_redis_hashes( $group ) ) {
879	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
880	if ( isset( $this->cache[ $multisite_safe_group ][ $key ] ) ) {
881	$value = $this->cache[ $multisite_safe_group ][ $key ];
882	}
883	} else {
884	$key = $this->_key( $key, $group );
885	if ( isset( $this->cache[ $key ] ) ) {
886	$value = $this->cache[ $key ];
887	}
888	}
889	if ( is_object( $value ) ) {
890	return clone $value;
891	}
892	return $value;
893	}
894
895	/**
896	* Set a value to the internal object cache
897	*
898	* @param string $key
899	* @param string $group
900	* @param mixed $value
901	*/
902	protected function _set_internal( $key, $group, $value ) {
903	// Redis converts null to an empty string
904	if ( is_null( $value ) ) {
905	$value = '';
906	}
907	if ( $this->_should_use_redis_hashes( $group ) ) {
908	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
909	if ( ! isset( $this->cache[ $multisite_safe_group ] ) ) {
910	$this->cache[ $multisite_safe_group ] = array();
911	}
912	$this->cache[ $multisite_safe_group ][ $key ] = $value;
913	} else {
914	$key = $this->_key( $key, $group );
915	$this->cache[ $key ] = $value;
916	}
917	}
918
919	/**
920	* Unset a value from the internal object cache
921	*
922	* @param string $key
923	* @param string $group
924	*/
925	protected function _unset_internal( $key, $group ) {
926	if ( $this->_should_use_redis_hashes( $group ) ) {
927	$multisite_safe_group = $this->multisite && ! isset( $this->global_groups[ $group ] ) ? $this->blog_prefix . $group : $group;
928	if ( isset( $this->cache[ $multisite_safe_group ][ $key ] ) ) {
929	unset( $this->cache[ $multisite_safe_group ][ $key ] );
930	}
931	} else {
932	$key = $this->_key( $key, $group );
933	if ( isset( $this->cache[ $key ] ) ) {
934	unset( $this->cache[ $key ] );
935	}
936	}
937	}
938
939	/**
940	* Utility function to generate the redis key for a given key and group.
941	*
942	* @param string $key The cache key.
943	* @param string $group The cache group.
944	* @return string A properly prefixed redis cache key.
945	*/
946	protected function _key( $key = '', $group = 'default' ) {
947	if ( empty( $group ) ) {
948	$group = 'default';
949	}
950
951	if ( ! empty( $this->global_groups[ $group ] ) ) {
952	$prefix = $this->global_prefix;
953	} else {
954	$prefix = $this->blog_prefix;
955	}
956
957	return preg_replace( '/\s+/', '', WP_CACHE_KEY_SALT . "$prefix$group:$key" );
958	}
959
960	/**
961	* Does this group use persistent storage?
962	*
963	* @param string $group Cache group.
964	* @return bool true if the group is persistent, false if not.
965	*/
966	protected function _should_persist( $group ) {
967	return empty( $this->non_persistent_groups[ $group ] );
968	}
969
970	/**
971	* Should this group use Redis hashes?
972	*
973	* @param string $group Cache group.
974	* @return bool True if the group should use Redis hashes, false if not.
975	*/
976	protected function _should_use_redis_hashes( $group ) {
977	if ( self::USE_GROUPS \|\| ! empty( $this->redis_hash_groups[ $group ] ) ) {
978	return true;
979	}
980	return false;
981	}
982
983	/**
984	* Wrapper method for connecting to Redis, which lets us retry the connection
985	*/
986	protected function _connect_redis() {
987	global $redis_server;
988
989	if ( ! class_exists( 'Redis' ) ) {
990	$this->is_redis_connected = false;
991	$this->missing_redis_message = 'Warning! PHPRedis module is unavailable, which is required by WP Redis object cache.';
992	return $this->is_redis_connected;
993	}
994
995	if ( empty( $redis_server ) ) {
996	# Attempt to automatically load Pantheon's Redis config from the env.
997	if ( isset( $_SERVER['CACHE_HOST'] ) ) {
998	$redis_server = array(
999	'host' => $_SERVER['CACHE_HOST'],
1000	'port' => $_SERVER['CACHE_PORT'],
1001	'auth' => $_SERVER['CACHE_PASSWORD'],
1002	);
1003	} else {
1004	$redis_server = array(
1005	'host' => '127.0.0.1',
1006	'port' => 6379,
1007	);
1008	}
1009	}
1010
1011	$this->redis = new Redis;
1012
1013	if ( file_exists( $redis_server['host'] ) && 'socket' === filetype( $redis_server['host'] ) ) { //unix socket connection
1014	//port must be null or socket won't connect
1015	$port = null;
1016	} else { //tcp connection
1017	$port = ! empty( $redis_server['port'] ) ? $redis_server['port'] : 6379;
1018	}
1019	$this->redis->connect( $redis_server['host'], $port, 1, null, 100 ); # 1s timeout, 100ms delay between reconnections
1020	foreach ( array( 'auth' => 'auth', 'database' => 'select' ) as $k => $method ) {
1021	if ( ! isset( $redis_server[ $k ] ) ) {
1022	continue;
1023	}
1024	try {
1025	$this->redis->$method( $redis_server[ $k ] );
1026	} catch ( RedisException $e ) {
1027	// PhpRedis throws an Exception when it fails a server call.
1028	// To prevent WordPress from fataling, we catch the Exception.
1029	try {
1030	$this->last_triggered_error = 'WP Redis: ' . $e->getMessage();
1031	// Be friendly to developers debugging production servers by triggering an error
1032	// @codingStandardsIgnoreStart
1033	trigger_error( $this->last_triggered_error, E_USER_WARNING );
1034	// @codingStandardsIgnoreEnd
1035	} catch ( PHPUnit_Framework_Error_Warning $e ) {
1036	// PHPUnit throws an Exception when `trigger_error()` is called.
1037	// To ensure our tests (which expect Exceptions to be caught) continue to run,
1038	// we catch the PHPUnit exception and inspect the RedisException message
1039	}
1040	}
1041	}
1042	$this->is_redis_connected = $this->redis->isConnected();
1043	if ( ! $this->is_redis_connected ) {
1044	$this->missing_redis_message = 'Warning! WP Redis object cache cannot connect to Redis server.';
1045	}
1046	return $this->is_redis_connected;
1047	}
1048
1049	/**
1050	* Wrapper method for calls to Redis, which fails gracefully when Redis is unavailable
1051	*
1052	* @param string $method
1053	* @param mixed $args
1054	* @return mixed
1055	*/
1056	protected function _call_redis( $method ) {
1057	global $wpdb;
1058
1059	$arguments = func_get_args();
1060	array_shift( $arguments ); // ignore $method
1061
1062	// $group is intended for the failback, and isn't passed to the Redis callback
1063	if ( 'hIncrBy' === $method ) {
1064	$group = array_pop( $arguments );
1065	}
1066
1067	if ( $this->is_redis_connected ) {
1068	try {
1069	if ( ! isset( $this->redis_calls[ $method ] ) ) {
1070	$this->redis_calls[ $method ] = 0;
1071	}
1072	$this->redis_calls[ $method ]++;
1073	$retval = call_user_func_array( array( $this->redis, $method ), $arguments );
1074	return $retval;
1075	} catch ( RedisException $e ) {
1076	// PhpRedis throws an Exception when it fails a server call.
1077	// To prevent WordPress from fataling, we catch the Exception.
1078	$retry_exception_messages = array( 'socket error on read socket', 'Connection closed', 'Redis server went away' );
1079	$retry_exception_messages = apply_filters( 'wp_redis_retry_exception_messages', $retry_exception_messages );
1080	if ( in_array( $e->getMessage(), $retry_exception_messages, true ) ) {
1081	try {
1082	$this->last_triggered_error = 'WP Redis: ' . $e->getMessage();
1083	// Be friendly to developers debugging production servers by triggering an error
1084	// @codingStandardsIgnoreStart
1085	trigger_error( $this->last_triggered_error, E_USER_WARNING );
1086	// @codingStandardsIgnoreEnd
1087	} catch ( PHPUnit_Framework_Error_Warning $e ) {
1088	// PHPUnit throws an Exception when `trigger_error()` is called.
1089	// To ensure our tests (which expect Exceptions to be caught) continue to run,
1090	// we catch the PHPUnit exception and inspect the RedisException message
1091	}
1092	// Attempt to refresh the connection if it was successfully established once
1093	// $this->is_redis_connected will be set inside _connect_redis()
1094	if ( $this->_connect_redis() ) {
1095	return call_user_func_array( array( $this, '_call_redis' ), array_merge( array( $method ), $arguments ) );
1096	}
1097	// Fall through to fallback below
1098	} else {
1099	throw $e;
1100	}
1101	}
1102	}
1103
1104	if ( $this->is_redis_failback_flush_enabled() && ! $this->do_redis_failback_flush && ! empty( $wpdb ) ) {
1105	if ( $this->multisite ) {
1106	$table = $wpdb->sitemeta;
1107	$col1 = 'meta_key';
1108	$col2 = 'meta_value';
1109	} else {
1110	$table = $wpdb->options;
1111	$col1 = 'option_name';
1112	$col2 = 'option_value';
1113	}
1114	// @codingStandardsIgnoreStart
1115	$wpdb->query( "INSERT IGNORE INTO {$table} ({$col1},{$col2}) VALUES ('wp_redis_do_redis_failback_flush',1)" );
1116	// @codingStandardsIgnoreEnd
1117	$this->do_redis_failback_flush = true;
1118	}
1119
1120	// Mock expected behavior from Redis for these methods
1121	switch ( $method ) {
1122	case 'incr':
1123	case 'incrBy':
1124	$val = $this->cache[ $arguments[0] ];
1125	$offset = isset( $arguments[1] ) && 'incrBy' === $method ? $arguments[1] : 1;
1126	$val = $val + $offset;
1127	return $val;
1128	case 'hIncrBy':
1129	$val = $this->_get_internal( $arguments[1], $group );
1130	return $val + $arguments[2];
1131	case 'decrBy':
1132	case 'decr':
1133	$val = $this->cache[ $arguments[0] ];
1134	$offset = isset( $arguments[1] ) && 'decrBy' === $method ? $arguments[1] : 1;
1135	$val = $val - $offset;
1136	return $val;
1137	case 'del':
1138	case 'hDel':
1139	return 1;
1140	case 'flushAll':
1141	case 'IsConnected':
1142	case 'exists':
1143	case 'get':
1144	case 'hGet':
1145	return false;
1146	}
1147
1148	}
1149
1150	/**
1151	* Admin UI to let the end user know something about the Redis connection isn't working.
1152	*/
1153	public function wp_action_admin_notices_warn_missing_redis() {
1154	if ( ! current_user_can( 'manage_options' ) \|\| empty( $this->missing_redis_message ) ) {
1155	return;
1156	}
1157	echo '<div class="message error"><p>' . esc_html( $this->missing_redis_message ) . '</p></div>';
1158	}
1159
1160	/**
1161	* Whether or not wakeup flush is enabled
1162	*
1163	* @return bool
1164	*/
1165	private function is_redis_failback_flush_enabled() {
1166	if ( defined( 'WP_INSTALLING' ) && WP_INSTALLING ) {
1167	return false;
1168	} elseif ( defined( 'WP_REDIS_DISABLE_FAILBACK_FLUSH' ) && WP_REDIS_DISABLE_FAILBACK_FLUSH ) {
1169	return false;
1170	}
1171	return true;
1172	}
1173
1174	/**
1175	* Sets up object properties; PHP 5 style constructor
1176	*
1177	* @return null\|WP_Object_Cache If cache is disabled, returns null.
1178	*/
1179	public function __construct() {
1180	global $blog_id, $table_prefix, $wpdb;
1181
1182	$this->multisite = is_multisite();
1183	$this->blog_prefix = $this->multisite ? $blog_id . ':' : '';
1184
1185	if ( ! $this->_connect_redis() && function_exists( 'add_action' ) ) {
1186	add_action( 'admin_notices', array( $this, 'wp_action_admin_notices_warn_missing_redis' ) );
1187	}
1188
1189	if ( $this->is_redis_failback_flush_enabled() && ! empty( $wpdb ) ) {
1190	if ( $this->multisite ) {
1191	$table = $wpdb->sitemeta;
1192	$col1 = 'meta_key';
1193	$col2 = 'meta_value';
1194	} else {
1195	$table = $wpdb->options;
1196	$col1 = 'option_name';
1197	$col2 = 'option_value';
1198	}
1199	// @codingStandardsIgnoreStart
1200	$this->do_redis_failback_flush = (bool) $wpdb->get_results( "SELECT {$col2} FROM {$table} WHERE {$col1}='wp_redis_do_redis_failback_flush'" );
1201	// @codingStandardsIgnoreEnd
1202	if ( $this->is_redis_connected && $this->do_redis_failback_flush ) {
1203	$ret = $this->_call_redis( 'flushAll' );
1204	if ( $ret ) {
1205	// @codingStandardsIgnoreStart
1206	$wpdb->query( "DELETE FROM {$table} WHERE {$col1}='wp_redis_do_redis_failback_flush'" );
1207	// @codingStandardsIgnoreEnd
1208	$this->do_redis_failback_flush = false;
1209	}
1210	}
1211	}
1212
1213	$this->global_prefix = ( $this->multisite \|\| defined( 'CUSTOM_USER_TABLE' ) && defined( 'CUSTOM_USER_META_TABLE' ) ) ? '' : $table_prefix;
1214
1215	/**
1216	* @todo This should be moved to the PHP4 style constructor, PHP5
1217	* already calls __destruct()
1218	*/
1219	register_shutdown_function( array( $this, '__destruct' ) );
1220	}
1221
1222	/**
1223	* Will save the object cache before object is completely destroyed.
1224	*
1225	* Called upon object destruction, which should be when PHP ends.
1226	*
1227	* @return bool True value. Won't be used by PHP
1228	*/
1229	public function __destruct() {
1230	return true;
1231	}
1232	}
1233