ultimate-wp-mail / lib / wp-background-processing / wp-background-process.php

wp-background-process.php in Ultimate WP Mail trunk, at lib/wp-background-processing/wp-background-process.php

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1	<?php
2	/**
3	* WP Background Process
4	*
5	* @package WP-Background-Processing
6	*/
7
8	/**
9	* Abstract WP_Background_Process class.
10	*
11	* @abstract
12	* @extends WP_Async_Request
13	*/
14	abstract class EWD_WP_Background_Process extends EWD_WP_Async_Request {
15
16	/**
17	* Action
18	*
19	* (default value: 'background_process')
20	*
21	* @var string
22	* @access protected
23	*/
24	protected $action = 'ewd_uwpm_background_process';
25
26	/**
27	* Start time of current process.
28	*
29	* (default value: 0)
30	*
31	* @var int
32	* @access protected
33	*/
34	protected $start_time = 0;
35
36	/**
37	* Cron_hook_identifier
38	*
39	* @var string
40	* @access protected
41	*/
42	protected $cron_hook_identifier;
43
44	/**
45	* Cron_interval_identifier
46	*
47	* @var string
48	* @access protected
49	*/
50	protected $cron_interval_identifier;
51
52	/**
53	* The status set when process is cancelling.
54	*
55	* @var int
56	*/
57	const STATUS_CANCELLED = 1;
58
59	/**
60	* The status set when process is paused or pausing.
61	*
62	* @var int;
63	*/
64	const STATUS_PAUSED = 2;
65
66	/**
67	* Initiate new background process.
68	*/
69	public function __construct() {
70	parent::__construct();
71
72	$this->cron_hook_identifier = $this->identifier . '_cron';
73	$this->cron_interval_identifier = $this->identifier . '_cron_interval';
74
75	add_action( $this->cron_hook_identifier, array( $this, 'handle_cron_healthcheck' ) );
76	add_filter( 'cron_schedules', array( $this, 'schedule_cron_healthcheck' ) );
77	}
78
79	/**
80	* Schedule the cron healthcheck and dispatch an async request to start processing the queue.
81	*
82	* @access public
83	* @return array\|WP_Error\|false HTTP Response array, WP_Error on failure, or false if not attempted.
84	*/
85	public function dispatch() {
86	if ( $this->is_processing() ) {
87	// Process already running.
88	return false;
89	}
90
91	// Schedule the cron healthcheck.
92	$this->schedule_event();
93
94	// Perform remote post.
95	return parent::dispatch();
96	}
97
98	/**
99	* Push to the queue.
100	*
101	* Note, save must be called in order to persist queued items to a batch for processing.
102	*
103	* @param mixed $data Data.
104	*
105	* @return $this
106	*/
107	public function push_to_queue( $data ) {
108	$this->data[] = $data;
109
110	return $this;
111	}
112
113	/**
114	* Save the queued items for future processing.
115	*
116	* @return $this
117	*/
118	public function save() {
119	$key = $this->generate_key();
120
121	if ( ! empty( $this->data ) ) {
122	update_site_option( $key, $this->data );
123	}
124
125	// Clean out data so that new data isn't prepended with closed session's data.
126	$this->data = array();
127
128	return $this;
129	}
130
131	/**
132	* Update a batch's queued items.
133	*
134	* @param string $key Key.
135	* @param array $data Data.
136	*
137	* @return $this
138	*/
139	public function update( $key, $data ) {
140	if ( ! empty( $data ) ) {
141	update_site_option( $key, $data );
142	}
143
144	return $this;
145	}
146
147	/**
148	* Delete a batch of queued items.
149	*
150	* @param string $key Key.
151	*
152	* @return $this
153	*/
154	public function delete( $key ) {
155	delete_site_option( $key );
156
157	return $this;
158	}
159
160	/**
161	* Delete entire job queue.
162	*/
163	public function delete_all() {
164	$batches = $this->get_batches();
165
166	foreach ( $batches as $batch ) {
167	$this->delete( $batch->key );
168	}
169
170	delete_site_option( $this->get_status_key() );
171
172	$this->cancelled();
173	}
174
175	/**
176	* Cancel job on next batch.
177	*/
178	public function cancel() {
179	update_site_option( $this->get_status_key(), self::STATUS_CANCELLED );
180
181	// Just in case the job was paused at the time.
182	$this->dispatch();
183	}
184
185	/**
186	* Has the process been cancelled?
187	*
188	* @return bool
189	*/
190	public function is_cancelled() {
191	$status = get_site_option( $this->get_status_key(), 0 );
192
193	if ( absint( $status ) === self::STATUS_CANCELLED ) {
194	return true;
195	}
196
197	return false;
198	}
199
200	/**
201	* Called when background process has been cancelled.
202	*/
203	protected function cancelled() {
204	do_action( $this->identifier . '_cancelled' );
205	}
206
207	/**
208	* Pause job on next batch.
209	*/
210	public function pause() {
211	update_site_option( $this->get_status_key(), self::STATUS_PAUSED );
212	}
213
214	/**
215	* Is the job paused?
216	*
217	* @return bool
218	*/
219	public function is_paused() {
220	$status = get_site_option( $this->get_status_key(), 0 );
221
222	if ( absint( $status ) === self::STATUS_PAUSED ) {
223	return true;
224	}
225
226	return false;
227	}
228
229	/**
230	* Called when background process has been paused.
231	*/
232	protected function paused() {
233	do_action( $this->identifier . '_paused' );
234	}
235
236	/**
237	* Resume job.
238	*/
239	public function resume() {
240	delete_site_option( $this->get_status_key() );
241
242	$this->schedule_event();
243	$this->dispatch();
244	$this->resumed();
245	}
246
247	/**
248	* Called when background process has been resumed.
249	*/
250	protected function resumed() {
251	do_action( $this->identifier . '_resumed' );
252	}
253
254	/**
255	* Is queued?
256	*
257	* @return bool
258	*/
259	public function is_queued() {
260	return ! $this->is_queue_empty();
261	}
262
263	/**
264	* Is the tool currently active, e.g. starting, working, paused or cleaning up?
265	*
266	* @return bool
267	*/
268	public function is_active() {
269	return $this->is_queued() \|\| $this->is_processing() \|\| $this->is_paused() \|\| $this->is_cancelled();
270	}
271
272	/**
273	* Generate key for a batch.
274	*
275	* Generates a unique key based on microtime. Queue items are
276	* given a unique key so that they can be merged upon save.
277	*
278	* @param int $length Optional max length to trim key to, defaults to 64 characters.
279	* @param string $key Optional string to append to identifier before hash, defaults to "batch".
280	*
281	* @return string
282	*/
283	protected function generate_key( $length = 64, $key = 'batch' ) {
284	$unique = md5( microtime() . wp_rand() );
285	$prepend = $this->identifier . '_' . $key . '_';
286
287	return substr( $prepend . $unique, 0, $length );
288	}
289
290	/**
291	* Get the status key.
292	*
293	* @return string
294	*/
295	protected function get_status_key() {
296	return $this->identifier . '_status';
297	}
298
299	/**
300	* Maybe process a batch of queued items.
301	*
302	* Checks whether data exists within the queue and that
303	* the process is not already running.
304	*/
305	public function maybe_handle() {
306	// Don't lock up other requests while processing.
307	session_write_close();
308
309	if ( $this->is_processing() ) {
310	// Background process already running.
311	return $this->maybe_wp_die();
312	}
313
314	if ( $this->is_cancelled() ) {
315	$this->clear_scheduled_event();
316	$this->delete_all();
317
318	return $this->maybe_wp_die();
319	}
320
321	if ( $this->is_paused() ) {
322	$this->clear_scheduled_event();
323	$this->paused();
324
325	return $this->maybe_wp_die();
326	}
327
328	if ( $this->is_queue_empty() ) {
329	// No data to process.
330	return $this->maybe_wp_die();
331	}
332
333	check_ajax_referer( $this->identifier, 'nonce' );
334
335	$this->handle();
336
337	return $this->maybe_wp_die();
338	}
339
340	/**
341	* Is queue empty?
342	*
343	* @return bool
344	*/
345	protected function is_queue_empty() {
346	return empty( $this->get_batch() );
347	}
348
349	/**
350	* Is process running?
351	*
352	* Check whether the current process is already running
353	* in a background process.
354	*
355	* @return bool
356	*
357	* @deprecated 1.1.0 Superseded.
358	* @see is_processing()
359	*/
360	protected function is_process_running() {
361	return $this->is_processing();
362	}
363
364	/**
365	* Is the background process currently running?
366	*
367	* @return bool
368	*/
369	public function is_processing() {
370	if ( get_site_transient( $this->identifier . '_process_lock' ) ) {
371	// Process already running.
372	return true;
373	}
374
375	return false;
376	}
377
378	/**
379	* Lock process.
380	*
381	* Lock the process so that multiple instances can't run simultaneously.
382	* Override if applicable, but the duration should be greater than that
383	* defined in the time_exceeded() method.
384	*/
385	protected function lock_process() {
386	$this->start_time = time(); // Set start time of current process.
387
388	$lock_duration = ( property_exists( $this, 'queue_lock_time' ) ) ? $this->queue_lock_time : 60; // 1 minute
389	$lock_duration = apply_filters( $this->identifier . '_queue_lock_time', $lock_duration );
390
391	set_site_transient( $this->identifier . '_process_lock', microtime(), $lock_duration );
392	}
393
394	/**
395	* Unlock process.
396	*
397	* Unlock the process so that other instances can spawn.
398	*
399	* @return $this
400	*/
401	protected function unlock_process() {
402	delete_site_transient( $this->identifier . '_process_lock' );
403
404	return $this;
405	}
406
407	/**
408	* Get batch.
409	*
410	* @return stdClass Return the first batch of queued items.
411	*/
412	protected function get_batch() {
413	return array_reduce(
414	$this->get_batches( 1 ),
415	function ( $carry, $batch ) {
416	return $batch;
417	},
418	array()
419	);
420	}
421
422	/**
423	* Get batches.
424	*
425	* @param int $limit Number of batches to return, defaults to all.
426	*
427	* @return array of stdClass
428	*/
429	public function get_batches( $limit = 0 ) {
430	global $wpdb;
431
432	if ( empty( $limit ) \|\| ! is_int( $limit ) ) {
433	$limit = 0;
434	}
435
436	$table = $wpdb->options;
437	$column = 'option_name';
438	$key_column = 'option_id';
439	$value_column = 'option_value';
440
441	if ( is_multisite() ) {
442	$table = $wpdb->sitemeta;
443	$column = 'meta_key';
444	$key_column = 'meta_id';
445	$value_column = 'meta_value';
446	}
447
448	$key = $wpdb->esc_like( $this->identifier . '_batch_' ) . '%';
449
450	$sql = '
451	SELECT *
452	FROM ' . $table . '
453	WHERE ' . $column . ' LIKE %s
454	ORDER BY ' . $key_column . ' ASC
455	';
456
457	$args = array( $key );
458
459	if ( ! empty( $limit ) ) {
460	$sql .= ' LIMIT %d';
461
462	$args[] = $limit;
463	}
464
465	$items = $wpdb->get_results( $wpdb->prepare( $sql, $args ) ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
466
467	$batches = array();
468
469	if ( ! empty( $items ) ) {
470	$batches = array_map(
471	function ( $item ) use ( $column, $value_column ) {
472	$batch = new stdClass();
473	$batch->key = $item->{$column};
474	$batch->data = maybe_unserialize( $item->{$value_column} );
475
476	return $batch;
477	},
478	$items
479	);
480	}
481
482	return $batches;
483	}
484
485	/**
486	* Handle a dispatched request.
487	*
488	* Pass each queue item to the task handler, while remaining
489	* within server memory and time limit constraints.
490	*/
491	protected function handle() {
492	$this->lock_process();
493
494	/**
495	* Number of seconds to sleep between batches. Defaults to 0 seconds, minimum 0.
496	*
497	* @param int $seconds
498	*/
499	$throttle_seconds = max(
500	0,
501	apply_filters(
502	$this->identifier . '_seconds_between_batches',
503	apply_filters(
504	$this->prefix . '_seconds_between_batches',
505	0
506	)
507	)
508	);
509
510	do {
511	$batch = $this->get_batch();
512
513	foreach ( $batch->data as $key => $value ) {
514	$task = $this->task( $value );
515
516	if ( false !== $task ) {
517	$batch->data[ $key ] = $task;
518	} else {
519	unset( $batch->data[ $key ] );
520	}
521
522	// Keep the batch up to date while processing it.
523	if ( ! empty( $batch->data ) ) {
524	$this->update( $batch->key, $batch->data );
525	}
526
527	// Let the server breathe a little.
528	sleep( $throttle_seconds );
529
530	if ( $this->time_exceeded() \|\| $this->memory_exceeded() ) {
531	// Batch limits reached.
532	break;
533	}
534	}
535
536	// Delete current batch if fully processed.
537	if ( empty( $batch->data ) ) {
538	$this->delete( $batch->key );
539	}
540	} while ( ! $this->time_exceeded() && ! $this->memory_exceeded() && ! $this->is_queue_empty() );
541
542	$this->unlock_process();
543
544	// Start next batch or complete process.
545	if ( ! $this->is_queue_empty() ) {
546	$this->dispatch();
547	} else {
548	$this->complete();
549	}
550
551	return $this->maybe_wp_die();
552	}
553
554	/**
555	* Memory exceeded?
556	*
557	* Ensures the batch process never exceeds 90%
558	* of the maximum WordPress memory.
559	*
560	* @return bool
561	*/
562	protected function memory_exceeded() {
563	$memory_limit = $this->get_memory_limit() * 0.9; // 90% of max memory
564	$current_memory = memory_get_usage( true );
565	$return = false;
566
567	if ( $current_memory >= $memory_limit ) {
568	$return = true;
569	}
570
571	return apply_filters( $this->identifier . '_memory_exceeded', $return );
572	}
573
574	/**
575	* Get memory limit in bytes.
576	*
577	* @return int
578	*/
579	protected function get_memory_limit() {
580	if ( function_exists( 'ini_get' ) ) {
581	$memory_limit = ini_get( 'memory_limit' );
582	} else {
583	// Sensible default.
584	$memory_limit = '128M';
585	}
586
587	if ( ! $memory_limit \|\| -1 === intval( $memory_limit ) ) {
588	// Unlimited, set to 32GB.
589	$memory_limit = '32000M';
590	}
591
592	return wp_convert_hr_to_bytes( $memory_limit );
593	}
594
595	/**
596	* Time limit exceeded?
597	*
598	* Ensures the batch never exceeds a sensible time limit.
599	* A timeout limit of 30s is common on shared hosting.
600	*
601	* @return bool
602	*/
603	protected function time_exceeded() {
604	$finish = $this->start_time + apply_filters( $this->identifier . '_default_time_limit', 20 ); // 20 seconds
605	$return = false;
606
607	if ( time() >= $finish ) {
608	$return = true;
609	}
610
611	return apply_filters( $this->identifier . '_time_exceeded', $return );
612	}
613
614	/**
615	* Complete processing.
616	*
617	* Override if applicable, but ensure that the below actions are
618	* performed, or, call parent::complete().
619	*/
620	protected function complete() {
621	delete_site_option( $this->get_status_key() );
622
623	// Remove the cron healthcheck job from the cron schedule.
624	$this->clear_scheduled_event();
625
626	$this->completed();
627	}
628
629	/**
630	* Called when background process has completed.
631	*/
632	protected function completed() {
633	do_action( $this->identifier . '_completed' );
634	}
635
636	/**
637	* Schedule the cron healthcheck job.
638	*
639	* @access public
640	*
641	* @param mixed $schedules Schedules.
642	*
643	* @return mixed
644	*/
645	public function schedule_cron_healthcheck( $schedules ) {
646	$interval = apply_filters( $this->cron_interval_identifier, 5 );
647
648	if ( property_exists( $this, 'cron_interval' ) ) {
649	$interval = apply_filters( $this->cron_interval_identifier, $this->cron_interval );
650	}
651
652	if ( 1 === $interval ) {
653	$display = __( 'Every Minute' );
654	} else {
655	$display = sprintf( __( 'Every %d Minutes' ), $interval );
656	}
657
658	// Adds an "Every NNN Minute(s)" schedule to the existing cron schedules.
659	$schedules[ $this->cron_interval_identifier ] = array(
660	'interval' => MINUTE_IN_SECONDS * $interval,
661	'display' => $display,
662	);
663
664	return $schedules;
665	}
666
667	/**
668	* Handle cron healthcheck event.
669	*
670	* Restart the background process if not already running
671	* and data exists in the queue.
672	*/
673	public function handle_cron_healthcheck() {
674	if ( $this->is_processing() ) {
675	// Background process already running.
676	exit;
677	}
678
679	if ( $this->is_queue_empty() ) {
680	// No data to process.
681	$this->clear_scheduled_event();
682	exit;
683	}
684
685	$this->dispatch();
686	}
687
688	/**
689	* Schedule the cron healthcheck event.
690	*/
691	protected function schedule_event() {
692	if ( ! wp_next_scheduled( $this->cron_hook_identifier ) ) {
693	wp_schedule_event( time(), $this->cron_interval_identifier, $this->cron_hook_identifier );
694	}
695	}
696
697	/**
698	* Clear scheduled cron healthcheck event.
699	*/
700	protected function clear_scheduled_event() {
701	$timestamp = wp_next_scheduled( $this->cron_hook_identifier );
702
703	if ( $timestamp ) {
704	wp_unschedule_event( $timestamp, $this->cron_hook_identifier );
705	}
706	}
707
708	/**
709	* Cancel the background process.
710	*
711	* Stop processing queue items, clear cron job and delete batch.
712	*
713	* @deprecated 1.1.0 Superseded.
714	* @see cancel()
715	*/
716	public function cancel_process() {
717	$this->cancel();
718	}
719
720	/**
721	* Perform task with queued item.
722	*
723	* Override this method to perform any actions required on each
724	* queue item. Return the modified item for further processing
725	* in the next pass through. Or, return false to remove the
726	* item from the queue.
727	*
728	* @param mixed $item Queue item to iterate over.
729	*
730	* @return mixed
731	*/
732	abstract protected function task( $item );
733	}
734