wordpress-seo / inc / sitemaps / class-sitemaps-cache-validator.php

class-sitemaps-cache-validator.php in Yoast SEO – Advanced SEO with real-time guidance and built-in AI 18.0, at inc/sitemaps/class-sitemaps-cache-validator.php

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1	<?php
2	/**
3	* WPSEO plugin file.
4	*
5	* @package WPSEO\XML_Sitemaps
6	*/
7
8	/**
9	* Handles storage keys for sitemaps caching and invalidation.
10	*
11	* @since 3.2
12	*/
13	class WPSEO_Sitemaps_Cache_Validator {
14
15	/**
16	* Prefix of the transient key for sitemap caches.
17	*
18	* @var string
19	*/
20	const STORAGE_KEY_PREFIX = 'yst_sm_';
21
22	/**
23	* Name of the option that holds the global validation value.
24	*
25	* @var string
26	*/
27	const VALIDATION_GLOBAL_KEY = 'wpseo_sitemap_cache_validator_global';
28
29	/**
30	* The format which creates the key of the option that holds the type validation value.
31	*
32	* @var string
33	*/
34	const VALIDATION_TYPE_KEY_FORMAT = 'wpseo_sitemap_%s_cache_validator';
35
36	/**
37	* Get the cache key for a certain type and page.
38	*
39	* A type of cache would be something like 'page', 'post' or 'video'.
40	*
41	* Example key format for sitemap type "post", page 1: wpseo_sitemap_post_1:akfw3e_23azBa .
42	*
43	* @since 3.2
44	*
45	* @param string\|null $type The type to get the key for. Null or self::SITEMAP_INDEX_TYPE for index cache.
46	* @param int $page The page of cache to get the key for.
47	*
48	* @return bool\|string The key where the cache is stored on. False if the key could not be generated.
49	*/
50	public static function get_storage_key( $type = null, $page = 1 ) {
51
52	// Using SITEMAP_INDEX_TYPE for sitemap index cache.
53	$type = is_null( $type ) ? WPSEO_Sitemaps::SITEMAP_INDEX_TYPE : $type;
54
55	$global_cache_validator = self::get_validator();
56	$type_cache_validator = self::get_validator( $type );
57
58	$prefix = self::STORAGE_KEY_PREFIX;
59	$postfix = sprintf( '_%d:%s_%s', $page, $global_cache_validator, $type_cache_validator );
60
61	try {
62	$type = self::truncate_type( $type, $prefix, $postfix );
63	} catch ( OutOfBoundsException $exception ) {
64	// Maybe do something with the exception, for now just mark as invalid.
65	return false;
66	}
67
68	// Build key.
69	$full_key = $prefix . $type . $postfix;
70
71	return $full_key;
72	}
73
74	/**
75	* If the type is over length make sure we compact it so we don't have any database problems.
76	*
77	* When there are more 'extremely long' post types, changes are they have variations in either the start or ending.
78	* Because of this, we cut out the excess in the middle which should result in less chance of collision.
79	*
80	* @since 3.2
81	*
82	* @param string $type The type of sitemap to be used.
83	* @param string $prefix The part before the type in the cache key. Only the length is used.
84	* @param string $postfix The part after the type in the cache key. Only the length is used.
85	*
86	* @return string The type with a safe length to use
87	*
88	* @throws OutOfRangeException When there is less than 15 characters of space for a key that is originally longer.
89	*/
90	public static function truncate_type( $type, $prefix = '', $postfix = '' ) {
91	/*
92	* This length has been restricted by the database column length of 64 in the past.
93	* The prefix added by WordPress is '_transient_' because we are saving to a transient.
94	* We need to use a timeout on the transient, otherwise the values get autoloaded, this adds
95	* another restriction to the length.
96	*/
97	$max_length = 45; // 64 - 19 ('_transient_timeout_')
98	$max_length -= strlen( $prefix );
99	$max_length -= strlen( $postfix );
100
101	if ( strlen( $type ) > $max_length ) {
102
103	if ( $max_length < 15 ) {
104	/*
105	* If this happens the most likely cause is a page number that is too high.
106	*
107	* So this would not happen unintentionally.
108	* Either by trying to cause a high server load, finding backdoors or misconfiguration.
109	*/
110	throw new OutOfRangeException(
111	__(
112	'Trying to build the sitemap cache key, but the postfix and prefix combination leaves too little room to do this. You are probably requesting a page that is way out of the expected range.',
113	'wordpress-seo'
114	)
115	);
116	}
117
118	$half = ( $max_length / 2 );
119
120	$first_part = substr( $type, 0, ( ceil( $half ) - 1 ) );
121	$last_part = substr( $type, ( 1 - floor( $half ) ) );
122
123	$type = $first_part . '..' . $last_part;
124	}
125
126	return $type;
127	}
128
129	/**
130	* Invalidate sitemap cache.
131	*
132	* @since 3.2
133	*
134	* @param string\|null $type The type to get the key for. Null for all caches.
135	*
136	* @return void
137	*/
138	public static function invalidate_storage( $type = null ) {
139
140	// Global validator gets cleared when no type is provided.
141	$old_validator = null;
142
143	// Get the current type validator.
144	if ( ! is_null( $type ) ) {
145	$old_validator = self::get_validator( $type );
146	}
147
148	// Refresh validator.
149	self::create_validator( $type );
150
151	if ( ! wp_using_ext_object_cache() ) {
152	// Clean up current cache from the database.
153	self::cleanup_database( $type, $old_validator );
154	}
155
156	// External object cache pushes old and unretrieved items out by itself so we don't have to do anything for that.
157	}
158
159	/**
160	* Cleanup invalidated database cache.
161	*
162	* @since 3.2
163	*
164	* @param string\|null $type The type of sitemap to clear cache for.
165	* @param string\|null $validator The validator to clear cache of.
166	*
167	* @return void
168	*/
169	public static function cleanup_database( $type = null, $validator = null ) {
170
171	global $wpdb;
172
173	if ( is_null( $type ) ) {
174	// Clear all cache if no type is provided.
175	$like = sprintf( '%s%%', self::STORAGE_KEY_PREFIX );
176	}
177	else {
178	// Clear type cache for all type keys.
179	$like = sprintf( '%1$s%2$s_%%', self::STORAGE_KEY_PREFIX, $type );
180	}
181
182	/*
183	* Add slashes to the LIKE "_" single character wildcard.
184	*
185	* We can't use `esc_like` here because we need the % in the query.
186	*/
187	$where = [];
188	$where[] = sprintf( "option_name LIKE '%s'", addcslashes( '_transient_' . $like, '_' ) );
189	$where[] = sprintf( "option_name LIKE '%s'", addcslashes( '_transient_timeout_' . $like, '_' ) );
190
191	// Delete transients.
192	$query = sprintf( 'DELETE FROM %1$s WHERE %2$s', $wpdb->options, implode( ' OR ', $where ) );
193	$wpdb->query( $query );
194
195	wp_cache_delete( 'alloptions', 'options' );
196	}
197
198	/**
199	* Get the current cache validator.
200	*
201	* Without the type the global validator is returned.
202	* This can invalidate -all- keys in cache at once.
203	*
204	* With the type parameter the validator for that specific type can be invalidated.
205	*
206	* @since 3.2
207	*
208	* @param string $type Provide a type for a specific type validator, empty for global validator.
209	*
210	* @return string\|null The validator for the supplied type.
211	*/
212	public static function get_validator( $type = '' ) {
213
214	$key = self::get_validator_key( $type );
215
216	$current = get_option( $key, null );
217	if ( ! is_null( $current ) ) {
218	return $current;
219	}
220
221	if ( self::create_validator( $type ) ) {
222	return self::get_validator( $type );
223	}
224
225	return null;
226	}
227
228	/**
229	* Get the cache validator option key for the specified type.
230	*
231	* @since 3.2
232	*
233	* @param string $type Provide a type for a specific type validator, empty for global validator.
234	*
235	* @return string Validator to be used to generate the cache key.
236	*/
237	public static function get_validator_key( $type = '' ) {
238
239	if ( empty( $type ) ) {
240	return self::VALIDATION_GLOBAL_KEY;
241	}
242
243	return sprintf( self::VALIDATION_TYPE_KEY_FORMAT, $type );
244	}
245
246	/**
247	* Refresh the cache validator value.
248	*
249	* @since 3.2
250	*
251	* @param string $type Provide a type for a specific type validator, empty for global validator.
252	*
253	* @return bool True if validator key has been saved as option.
254	*/
255	public static function create_validator( $type = '' ) {
256
257	$key = self::get_validator_key( $type );
258
259	// Generate new validator.
260	$microtime = microtime();
261
262	// Remove space.
263	list( $milliseconds, $seconds ) = explode( ' ', $microtime );
264
265	// Transients are purged every 24h.
266	$seconds = ( $seconds % DAY_IN_SECONDS );
267	$milliseconds = intval( substr( $milliseconds, 2, 3 ), 10 );
268
269	// Combine seconds and milliseconds and convert to integer.
270	$validator = intval( $seconds . '' . $milliseconds, 10 );
271
272	// Apply base 61 encoding.
273	$compressed = self::convert_base10_to_base61( $validator );
274
275	return update_option( $key, $compressed, false );
276	}
277
278	/**
279	* Encode to base61 format.
280	*
281	* This is base64 (numeric + alpha + alpha upper case) without the 0.
282	*
283	* @since 3.2
284	*
285	* @param int $base10 The number that has to be converted to base 61.
286	*
287	* @return string Base 61 converted string.
288	*
289	* @throws InvalidArgumentException When the input is not an integer.
290	*/
291	public static function convert_base10_to_base61( $base10 ) {
292
293	if ( ! is_int( $base10 ) ) {
294	throw new InvalidArgumentException( __( 'Expected an integer as input.', 'wordpress-seo' ) );
295	}
296
297	// Characters that will be used in the conversion.
298	$characters = '123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
299	$length = strlen( $characters );
300
301	$remainder = $base10;
302	$output = '';
303
304	do {
305	// Building from right to left in the result.
306	$index = ( $remainder % $length );
307
308	// Prepend the character to the output.
309	$output = $characters[ $index ] . $output;
310
311	// Determine the remainder after removing the applied number.
312	$remainder = floor( $remainder / $length );
313
314	// Keep doing it until we have no remainder left.
315	} while ( $remainder );
316
317	return $output;
318	}
319	}
320