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wp-background-process.php
507 lines
| 1 | <?php |
| 2 | /** |
| 3 | * WP Background Process |
| 4 | * |
| 5 | * @package WP-Background-Processing |
| 6 | */ |
| 7 | |
| 8 | if ( ! class_exists( 'WP_Background_Process' ) ) { |
| 9 | |
| 10 | /** |
| 11 | * Abstract WP_Background_Process class. |
| 12 | * |
| 13 | * @abstract |
| 14 | * @extends WP_Async_Request |
| 15 | */ |
| 16 | abstract class WP_Background_Process extends WP_Async_Request { |
| 17 | |
| 18 | /** |
| 19 | * Action |
| 20 | * |
| 21 | * (default value: 'background_process') |
| 22 | * |
| 23 | * @var string |
| 24 | * @access protected |
| 25 | */ |
| 26 | protected $action = 'background_process'; |
| 27 | |
| 28 | /** |
| 29 | * Start time of current process. |
| 30 | * |
| 31 | * (default value: 0) |
| 32 | * |
| 33 | * @var int |
| 34 | * @access protected |
| 35 | */ |
| 36 | protected $start_time = 0; |
| 37 | |
| 38 | /** |
| 39 | * Cron_hook_identifier |
| 40 | * |
| 41 | * @var mixed |
| 42 | * @access protected |
| 43 | */ |
| 44 | protected $cron_hook_identifier; |
| 45 | |
| 46 | /** |
| 47 | * Cron_interval_identifier |
| 48 | * |
| 49 | * @var mixed |
| 50 | * @access protected |
| 51 | */ |
| 52 | protected $cron_interval_identifier; |
| 53 | |
| 54 | /** |
| 55 | * Initiate new background process |
| 56 | */ |
| 57 | public function __construct() { |
| 58 | parent::__construct(); |
| 59 | |
| 60 | $this->cron_hook_identifier = $this->identifier . '_cron'; |
| 61 | $this->cron_interval_identifier = $this->identifier . '_cron_interval'; |
| 62 | |
| 63 | add_action( $this->cron_hook_identifier, array( $this, 'handle_cron_healthcheck' ) ); |
| 64 | add_filter( 'cron_schedules', array( $this, 'schedule_cron_healthcheck' ) ); |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Dispatch |
| 69 | * |
| 70 | * @access public |
| 71 | * @return void |
| 72 | */ |
| 73 | public function dispatch() { |
| 74 | // Schedule the cron healthcheck. |
| 75 | $this->schedule_event(); |
| 76 | |
| 77 | // Perform remote post. |
| 78 | return parent::dispatch(); |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Push to queue |
| 83 | * |
| 84 | * @param mixed $data Data. |
| 85 | * |
| 86 | * @return $this |
| 87 | */ |
| 88 | public function push_to_queue( $data ) { |
| 89 | $this->data[] = $data; |
| 90 | |
| 91 | return $this; |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * Save queue |
| 96 | * |
| 97 | * @return $this |
| 98 | */ |
| 99 | public function save() { |
| 100 | $key = $this->generate_key(); |
| 101 | |
| 102 | if ( ! empty( $this->data ) ) { |
| 103 | update_site_option( $key, $this->data ); |
| 104 | } |
| 105 | |
| 106 | return $this; |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * Update queue |
| 111 | * |
| 112 | * @param string $key Key. |
| 113 | * @param array $data Data. |
| 114 | * |
| 115 | * @return $this |
| 116 | */ |
| 117 | public function update( $key, $data ) { |
| 118 | if ( ! empty( $data ) ) { |
| 119 | update_site_option( $key, $data ); |
| 120 | } |
| 121 | |
| 122 | return $this; |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Delete queue |
| 127 | * |
| 128 | * @param string $key Key. |
| 129 | * |
| 130 | * @return $this |
| 131 | */ |
| 132 | public function delete( $key ) { |
| 133 | delete_site_option( $key ); |
| 134 | |
| 135 | return $this; |
| 136 | } |
| 137 | |
| 138 | /** |
| 139 | * Generate key |
| 140 | * |
| 141 | * Generates a unique key based on microtime. Queue items are |
| 142 | * given a unique key so that they can be merged upon save. |
| 143 | * |
| 144 | * @param int $length Length. |
| 145 | * |
| 146 | * @return string |
| 147 | */ |
| 148 | protected function generate_key( $length = 64 ) { |
| 149 | $unique = md5( microtime() . rand() ); |
| 150 | $prepend = $this->identifier . '_batch_'; |
| 151 | |
| 152 | return substr( $prepend . $unique, 0, $length ); |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Maybe process queue |
| 157 | * |
| 158 | * Checks whether data exists within the queue and that |
| 159 | * the process is not already running. |
| 160 | */ |
| 161 | public function maybe_handle() { |
| 162 | // Don't lock up other requests while processing |
| 163 | session_write_close(); |
| 164 | |
| 165 | if ( $this->is_process_running() ) { |
| 166 | // Background process already running. |
| 167 | wp_die(); |
| 168 | } |
| 169 | |
| 170 | if ( $this->is_queue_empty() ) { |
| 171 | // No data to process. |
| 172 | wp_die(); |
| 173 | } |
| 174 | |
| 175 | check_ajax_referer( $this->identifier, 'nonce' ); |
| 176 | |
| 177 | $this->handle(); |
| 178 | |
| 179 | wp_die(); |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * Is queue empty |
| 184 | * |
| 185 | * @return bool |
| 186 | */ |
| 187 | protected function is_queue_empty() { |
| 188 | global $wpdb; |
| 189 | |
| 190 | $table = $wpdb->options; |
| 191 | $column = 'option_name'; |
| 192 | |
| 193 | if ( is_multisite() ) { |
| 194 | $table = $wpdb->sitemeta; |
| 195 | $column = 'meta_key'; |
| 196 | } |
| 197 | |
| 198 | $key = $this->identifier . '_batch_%'; |
| 199 | |
| 200 | $count = $wpdb->get_var( $wpdb->prepare( " |
| 201 | SELECT COUNT(*) |
| 202 | FROM {$table} |
| 203 | WHERE {$column} LIKE %s |
| 204 | ", $key ) ); |
| 205 | |
| 206 | return ( $count > 0 ) ? false : true; |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Is process running |
| 211 | * |
| 212 | * Check whether the current process is already running |
| 213 | * in a background process. |
| 214 | */ |
| 215 | public function is_process_running() { |
| 216 | if ( get_site_transient( $this->identifier . '_process_lock' ) ) { |
| 217 | // Process already running. |
| 218 | return true; |
| 219 | } |
| 220 | |
| 221 | return false; |
| 222 | } |
| 223 | |
| 224 | /** |
| 225 | * Lock process |
| 226 | * |
| 227 | * Lock the process so that multiple instances can't run simultaneously. |
| 228 | * Override if applicable, but the duration should be greater than that |
| 229 | * defined in the time_exceeded() method. |
| 230 | */ |
| 231 | protected function lock_process() { |
| 232 | $this->start_time = time(); // Set start time of current process. |
| 233 | |
| 234 | $lock_duration = ( property_exists( $this, 'queue_lock_time' ) ) ? $this->queue_lock_time : 60; // 1 minute |
| 235 | $lock_duration = apply_filters( $this->identifier . '_queue_lock_time', $lock_duration ); |
| 236 | |
| 237 | set_site_transient( $this->identifier . '_process_lock', microtime(), $lock_duration ); |
| 238 | } |
| 239 | |
| 240 | /** |
| 241 | * Unlock process |
| 242 | * |
| 243 | * Unlock the process so that other instances can spawn. |
| 244 | * |
| 245 | * @return $this |
| 246 | */ |
| 247 | protected function unlock_process() { |
| 248 | delete_site_transient( $this->identifier . '_process_lock' ); |
| 249 | |
| 250 | return $this; |
| 251 | } |
| 252 | |
| 253 | /** |
| 254 | * Get batch |
| 255 | * |
| 256 | * @return stdClass Return the first batch from the queue |
| 257 | */ |
| 258 | protected function get_batch() { |
| 259 | global $wpdb; |
| 260 | |
| 261 | $table = $wpdb->options; |
| 262 | $column = 'option_name'; |
| 263 | $key_column = 'option_id'; |
| 264 | $value_column = 'option_value'; |
| 265 | |
| 266 | if ( is_multisite() ) { |
| 267 | $table = $wpdb->sitemeta; |
| 268 | $column = 'meta_key'; |
| 269 | $key_column = 'meta_id'; |
| 270 | $value_column = 'meta_value'; |
| 271 | } |
| 272 | |
| 273 | $key = $this->identifier . '_batch_%'; |
| 274 | |
| 275 | $query = $wpdb->get_row( $wpdb->prepare( " |
| 276 | SELECT * |
| 277 | FROM {$table} |
| 278 | WHERE {$column} LIKE %s |
| 279 | ORDER BY {$key_column} ASC |
| 280 | LIMIT 1 |
| 281 | ", $key ) ); |
| 282 | |
| 283 | $batch = new stdClass(); |
| 284 | $batch->key = $query->$column; |
| 285 | $batch->data = maybe_unserialize( $query->$value_column ); |
| 286 | |
| 287 | return $batch; |
| 288 | } |
| 289 | |
| 290 | /** |
| 291 | * Handle |
| 292 | * |
| 293 | * Pass each queue item to the task handler, while remaining |
| 294 | * within server memory and time limit constraints. |
| 295 | */ |
| 296 | protected function handle() { |
| 297 | $this->lock_process(); |
| 298 | |
| 299 | do { |
| 300 | $batch = $this->get_batch(); |
| 301 | |
| 302 | foreach ( $batch->data as $key => $value ) { |
| 303 | $task = $this->task( $value ); |
| 304 | |
| 305 | if ( false !== $task ) { |
| 306 | $batch->data[ $key ] = $task; |
| 307 | } else { |
| 308 | unset( $batch->data[ $key ] ); |
| 309 | } |
| 310 | |
| 311 | if ( $this->time_exceeded() || $this->memory_exceeded() ) { |
| 312 | // Batch limits reached. |
| 313 | break; |
| 314 | } |
| 315 | } |
| 316 | |
| 317 | // Update or delete current batch. |
| 318 | if ( ! empty( $batch->data ) ) { |
| 319 | $this->update( $batch->key, $batch->data ); |
| 320 | } else { |
| 321 | $this->delete( $batch->key ); |
| 322 | } |
| 323 | } while ( ! $this->time_exceeded() && ! $this->memory_exceeded() && ! $this->is_queue_empty() ); |
| 324 | |
| 325 | $this->unlock_process(); |
| 326 | |
| 327 | // Start next batch or complete process. |
| 328 | if ( ! $this->is_queue_empty() ) { |
| 329 | $this->dispatch(); |
| 330 | } else { |
| 331 | $this->complete(); |
| 332 | } |
| 333 | |
| 334 | wp_die(); |
| 335 | } |
| 336 | |
| 337 | /** |
| 338 | * Memory exceeded |
| 339 | * |
| 340 | * Ensures the batch process never exceeds 90% |
| 341 | * of the maximum WordPress memory. |
| 342 | * |
| 343 | * @return bool |
| 344 | */ |
| 345 | protected function memory_exceeded() { |
| 346 | $memory_limit = $this->get_memory_limit() * 0.9; // 90% of max memory |
| 347 | $current_memory = memory_get_usage( true ); |
| 348 | $return = false; |
| 349 | |
| 350 | if ( $current_memory >= $memory_limit ) { |
| 351 | $return = true; |
| 352 | } |
| 353 | |
| 354 | return apply_filters( $this->identifier . '_memory_exceeded', $return ); |
| 355 | } |
| 356 | |
| 357 | /** |
| 358 | * Get memory limit |
| 359 | * |
| 360 | * @return int |
| 361 | */ |
| 362 | protected function get_memory_limit() { |
| 363 | if ( function_exists( 'ini_get' ) ) { |
| 364 | $memory_limit = ini_get( 'memory_limit' ); |
| 365 | } else { |
| 366 | // Sensible default. |
| 367 | $memory_limit = '128M'; |
| 368 | } |
| 369 | |
| 370 | if ( ! $memory_limit || -1 === $memory_limit ) { |
| 371 | // Unlimited, set to 32GB. |
| 372 | $memory_limit = '32000M'; |
| 373 | } |
| 374 | |
| 375 | return intval( $memory_limit ) * 1024 * 1024; |
| 376 | } |
| 377 | |
| 378 | /** |
| 379 | * Time exceeded. |
| 380 | * |
| 381 | * Ensures the batch never exceeds a sensible time limit. |
| 382 | * A timeout limit of 30s is common on shared hosting. |
| 383 | * |
| 384 | * @return bool |
| 385 | */ |
| 386 | protected function time_exceeded() { |
| 387 | $finish = $this->start_time + apply_filters( $this->identifier . '_default_time_limit', 20 ); // 20 seconds |
| 388 | $return = false; |
| 389 | |
| 390 | if ( time() >= $finish ) { |
| 391 | $return = true; |
| 392 | } |
| 393 | |
| 394 | return apply_filters( $this->identifier . '_time_exceeded', $return ); |
| 395 | } |
| 396 | |
| 397 | /** |
| 398 | * Complete. |
| 399 | * |
| 400 | * Override if applicable, but ensure that the below actions are |
| 401 | * performed, or, call parent::complete(). |
| 402 | */ |
| 403 | protected function complete() { |
| 404 | // Unschedule the cron healthcheck. |
| 405 | $this->clear_scheduled_event(); |
| 406 | } |
| 407 | |
| 408 | /** |
| 409 | * Schedule cron healthcheck |
| 410 | * |
| 411 | * @access public |
| 412 | * @param mixed $schedules Schedules. |
| 413 | * @return mixed |
| 414 | */ |
| 415 | public function schedule_cron_healthcheck( $schedules ) { |
| 416 | $interval = apply_filters( $this->identifier . '_cron_interval', 5 ); |
| 417 | |
| 418 | if ( property_exists( $this, 'cron_interval' ) ) { |
| 419 | $interval = apply_filters( $this->identifier . '_cron_interval', $this->cron_interval_identifier ); |
| 420 | } |
| 421 | |
| 422 | // Adds every 5 minutes to the existing schedules. |
| 423 | $schedules[ $this->identifier . '_cron_interval' ] = array( |
| 424 | 'interval' => MINUTE_IN_SECONDS * $interval, |
| 425 | 'display' => sprintf( __( 'Every %d Minutes' ), $interval ), |
| 426 | ); |
| 427 | |
| 428 | return $schedules; |
| 429 | } |
| 430 | |
| 431 | /** |
| 432 | * Handle cron healthcheck |
| 433 | * |
| 434 | * Restart the background process if not already running |
| 435 | * and data exists in the queue. |
| 436 | */ |
| 437 | public function handle_cron_healthcheck() { |
| 438 | if ( $this->is_process_running() ) { |
| 439 | // Background process already running. |
| 440 | exit; |
| 441 | } |
| 442 | |
| 443 | if ( $this->is_queue_empty() ) { |
| 444 | // No data to process. |
| 445 | $this->clear_scheduled_event(); |
| 446 | exit; |
| 447 | } |
| 448 | |
| 449 | $this->handle(); |
| 450 | |
| 451 | exit; |
| 452 | } |
| 453 | |
| 454 | /** |
| 455 | * Schedule event |
| 456 | */ |
| 457 | protected function schedule_event() { |
| 458 | if ( ! wp_next_scheduled( $this->cron_hook_identifier ) ) { |
| 459 | wp_schedule_event( time(), $this->cron_interval_identifier, $this->cron_hook_identifier ); |
| 460 | } |
| 461 | } |
| 462 | |
| 463 | /** |
| 464 | * Clear scheduled event |
| 465 | */ |
| 466 | protected function clear_scheduled_event() { |
| 467 | $timestamp = wp_next_scheduled( $this->cron_hook_identifier ); |
| 468 | |
| 469 | if ( $timestamp ) { |
| 470 | wp_unschedule_event( $timestamp, $this->cron_hook_identifier ); |
| 471 | } |
| 472 | } |
| 473 | |
| 474 | /** |
| 475 | * Cancel Process |
| 476 | * |
| 477 | * Stop processing queue items, clear cronjob and delete batch. |
| 478 | * |
| 479 | */ |
| 480 | public function cancel_process() { |
| 481 | if ( ! $this->is_queue_empty() ) { |
| 482 | $batch = $this->get_batch(); |
| 483 | |
| 484 | $this->delete( $batch->key ); |
| 485 | |
| 486 | wp_clear_scheduled_hook( $this->cron_hook_identifier ); |
| 487 | } |
| 488 | |
| 489 | } |
| 490 | |
| 491 | /** |
| 492 | * Task |
| 493 | * |
| 494 | * Override this method to perform any actions required on each |
| 495 | * queue item. Return the modified item for further processing |
| 496 | * in the next pass through. Or, return false to remove the |
| 497 | * item from the queue. |
| 498 | * |
| 499 | * @param mixed $item Queue item to iterate over. |
| 500 | * |
| 501 | * @return mixed |
| 502 | */ |
| 503 | abstract protected function task( $item ); |
| 504 | |
| 505 | } |
| 506 | } |
| 507 |