jetpack / jetpack_vendor / automattic / jetpack-stats / src / class-transient-cleanup.php

class-transient-cleanup.php in Jetpack – WP Security, Backup, Speed, & Growth 16.3-beta, at jetpack_vendor/automattic/jetpack-stats/src/class-transient-cleanup.php

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1	<?php
2	/**
3	* Stats Transient Cleanup
4	*
5	* Handles cleanup of expired stats cache transients to prevent database bloat
6	* on sites without a persistent object cache.
7	*
8	* Adapted from Brute Force Protection transient cleanup.
9	*
10	* @package automattic/jetpack-stats
11	*/
12
13	namespace Automattic\Jetpack\Stats;
14
15	/**
16	* Transient_Cleanup class.
17	*
18	* Provides a scheduled cron job to clean up expired stats transients.
19	* WordPress transient garbage collection is "lazy" - expired transients are only
20	* deleted when accessed via get_transient(). Stats transients use dynamic cache keys
21	* based on query parameters, so expired entries are rarely accessed again and
22	* accumulate indefinitely in wp_options on sites without an external object cache.
23	*
24	* @since 0.18.0
25	*/
26	class Transient_Cleanup {
27
28	/**
29	* Cron hook name.
30	*/
31	const CRON_HOOK = 'jetpack_stats_transient_cleanup';
32
33	/**
34	* Batch size for transient cleanup.
35	*
36	* Used as the SQL LIMIT per prefix and as the threshold for stopping iteration.
37	* Actual deletions per run may slightly exceed this when processing multiple prefixes.
38	*/
39	const BATCH_SIZE = 5000;
40
41	/**
42	* Cron interval in seconds (8 hours).
43	*/
44	const CRON_INTERVAL = 28800;
45
46	/**
47	* Initialize the transient cleanup.
48	*
49	* @return void
50	*/
51	public static function init() {
52	// Register the cron hook.
53	add_action( self::CRON_HOOK, array( static::class, 'run_cleanup' ) );
54
55	// Register custom cron schedule.
56	// phpcs:ignore WordPress.WP.CronInterval.ChangeDetected -- 8 hours is intentional for batched transient cleanup.
57	add_filter( 'cron_schedules', array( static::class, 'add_cron_schedule' ) );
58
59	// Schedule the cron job if not already scheduled.
60	add_action( 'admin_init', array( static::class, 'schedule_cleanup' ) );
61	}
62
63	/**
64	* Add custom cron schedule for 8-hour intervals.
65	*
66	* @param array $schedules Existing cron schedules.
67	* @return array Modified cron schedules.
68	*/
69	public static function add_cron_schedule( $schedules ) {
70	if ( ! isset( $schedules['jetpack_stats_eight_hours'] ) ) {
71	$schedules['jetpack_stats_eight_hours'] = array(
72	'interval' => self::CRON_INTERVAL,
73	'display' => __( 'Every Eight Hours', 'jetpack-stats-pkg' ),
74	);
75	}
76	return $schedules;
77	}
78
79	/**
80	* Schedule the cleanup cron job.
81	*
82	* Skips scheduling on sites with persistent object cache since transients
83	* auto-expire there and cleanup is unnecessary.
84	*
85	* @return void
86	*/
87	public static function schedule_cleanup() {
88	// Skip scheduling on sites with persistent object cache - not needed there.
89	if ( wp_using_ext_object_cache() ) {
90	// Unschedule if it was previously scheduled (e.g., object cache was added later).
91	if ( wp_next_scheduled( self::CRON_HOOK ) ) {
92	wp_clear_scheduled_hook( self::CRON_HOOK );
93	}
94	return;
95	}
96
97	if ( ! wp_next_scheduled( self::CRON_HOOK ) ) {
98	wp_schedule_event( time() + self::CRON_INTERVAL, 'jetpack_stats_eight_hours', self::CRON_HOOK );
99	}
100	}
101
102	/**
103	* Unschedule the cleanup cron job.
104	* Hooked to 'jetpack_deactivate_module_stats' in Main::__construct().
105	*
106	* @return void
107	*/
108	public static function unschedule_cleanup() {
109	wp_clear_scheduled_hook( self::CRON_HOOK );
110	}
111
112	/**
113	* Get the list of transient prefixes to clean up.
114	*
115	* @return array List of transient prefixes.
116	*/
117	public static function get_transient_prefixes() {
118	$prefixes = array(
119	WPCOM_Stats::STATS_CACHE_TRANSIENT_PREFIX, // jetpack_restapi_stats_cache_
120	);
121
122	/**
123	* Filter the list of transient prefixes to clean up.
124	*
125	* @since 0.18.0
126	*
127	* @param array $prefixes List of transient prefixes.
128	*/
129	$filtered = apply_filters( 'jetpack_stats_transient_cleanup_prefixes', $prefixes );
130
131	// Normalize filtered value: ensure array, filter to non-empty strings, dedupe.
132	if ( ! is_array( $filtered ) ) {
133	$filtered = $prefixes;
134	}
135
136	$filtered = array_filter(
137	$filtered,
138	function ( $prefix ) {
139	return is_string( $prefix ) && '' !== $prefix;
140	}
141	);
142
143	return array_unique( $filtered );
144	}
145
146	/**
147	* Run the transient cleanup.
148	*
149	* @return int\|false Number of deleted transient options (two entries per transient), or false if skipped.
150	*/
151	public static function run_cleanup() {
152	/**
153	* Filter to disable transient cleanup.
154	*
155	* @since 0.18.0
156	*
157	* @param bool $disabled Whether to disable transient cleanup. Default false.
158	*/
159	if ( apply_filters( 'jetpack_stats_transient_cleanup_disabled', false ) ) {
160	return false;
161	}
162
163	// Skip if using external object cache - transients auto-expire there.
164	if ( wp_using_ext_object_cache() ) {
165	return false;
166	}
167
168	$total_deleted = 0;
169	$prefixes = self::get_transient_prefixes();
170
171	foreach ( $prefixes as $prefix ) {
172	$deleted = self::purge_expired_transients( $prefix );
173	$total_deleted += $deleted;
174
175	// Stop processing additional prefixes once we've reached the batch threshold.
176	// Note: total may exceed BATCH_SIZE since each prefix can delete up to BATCH_SIZE.
177	if ( $total_deleted >= self::BATCH_SIZE ) {
178	break;
179	}
180	}
181
182	return $total_deleted;
183	}
184
185	/**
186	* Purge expired transients for a specific prefix.
187	*
188	* @param string $prefix The transient prefix to clean up.
189	* @return int Number of deleted transient options, two entries for each transient.
190	*/
191	private static function purge_expired_transients( $prefix ) {
192	global $wpdb;
193
194	$now = time();
195	$timeout_prefix = '_transient_timeout_' . $prefix;
196	$like_pattern = $wpdb->esc_like( $timeout_prefix ) . '%';
197
198	// Find expired transients by querying timeout entries.
199	// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
200	$transients = $wpdb->get_col(
201	$wpdb->prepare(
202	"SELECT SUBSTRING(option_name, %d) AS transient_name FROM {$wpdb->options} WHERE option_name LIKE %s AND option_value < %d LIMIT %d",
203	strlen( $timeout_prefix ) + 1,
204	$like_pattern,
205	$now,
206	self::BATCH_SIZE
207	)
208	);
209
210	if ( empty( $transients ) ) {
211	return 0;
212	}
213
214	// Build list of option names to delete (both transient and timeout entries).
215	$option_names = array();
216	foreach ( $transients as $transient ) {
217	$option_names[] = '_transient_' . $prefix . $transient;
218	$option_names[] = '_transient_timeout_' . $prefix . $transient;
219	}
220
221	// Delete in chunks to avoid excessively long SQL queries.
222	// Each option name can be ~80 chars, so 50 items ≈ 4KB per query.
223	$chunks = array_chunk( $option_names, 50 );
224	$total_deleted = 0;
225
226	foreach ( $chunks as $chunk ) {
227	$placeholders = implode( ', ', array_fill( 0, count( $chunk ), '%s' ) );
228
229	// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
230	$result = $wpdb->query(
231	$wpdb->prepare(
232	"DELETE FROM {$wpdb->options} WHERE option_name IN ($placeholders)", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare -- $placeholders is a list of %s.
233	$chunk
234	)
235	);
236
237	if ( false !== $result ) {
238	$total_deleted += $result;
239	}
240	}
241
242	return $total_deleted;
243	}
244	}
245