<?php
namespace Simply_Static;
/**
* WP Background Process
*
* Copied from: https://github.com/deliciousbrains/wp-background-processing/tree/master
* Copied version: 1.4.0
*
* @package WP-Background-Processing
*/
/**
* Abstract Background_Process class.
*
* @abstract
* @extends Async_Request
*/
abstract class Background_Process extends Async_Request {
/**
* The default query arg name used for passing the chain ID to new processes.
*/
const CHAIN_ID_ARG_NAME = 'chain_id';
/**
* Unique background process chain ID.
*
* @var string
*/
private $chain_id;
/**
* Whether the background process is switched to process
* a batch from another blog in the multisite
*
* @var bool
*/
private $switched_to_blog = false;
/**
* Action
*
* (default value: 'background_process')
*
* @var string
* @access protected
*/
protected $action = 'background_process';
/**
* Start time of current process.
*
* (default value: 0)
*
* @var int
* @access protected
*/
protected $start_time = 0;
/**
* Cron_hook_identifier
*
* @var string
* @access protected
*/
protected $cron_hook_identifier;
/**
* Cron_interval_identifier
*
* @var string
* @access protected
*/
protected $cron_interval_identifier;
/**
* Restrict object instantiation when using unserialize.
*
* @var bool|array
*/
protected $allowed_batch_data_classes = true;
/**
* Amount of seconds to sleep() between batches
*
* @var int
*/
protected $seconds_between_batches = 0;
/**
* The status set when process is cancelling.
*
* @var int
*/
const STATUS_CANCELLED = 1;
/**
* The status set when process is paused or pausing.
*
* @var int;
*/
const STATUS_PAUSED = 2;
/**
* Initiate new background process.
*
* @param bool|array $allowed_batch_data_classes Optional. Array of class names that can be unserialized. Default true (any class).
*/
public function __construct( $allowed_batch_data_classes = true ) {
parent::__construct();
if ( empty( $allowed_batch_data_classes ) && false !== $allowed_batch_data_classes ) {
$allowed_batch_data_classes = true;
}
if ( ! is_bool( $allowed_batch_data_classes ) && ! is_array( $allowed_batch_data_classes ) ) {
$allowed_batch_data_classes = true;
}
// If allowed_batch_data_classes property set in subclass,
// only apply override if not allowing any class.
if ( true === $this->allowed_batch_data_classes || true !== $allowed_batch_data_classes ) {
$this->allowed_batch_data_classes = $allowed_batch_data_classes;
}
$this->cron_hook_identifier = $this->identifier . '_cron';
$this->cron_interval_identifier = $this->identifier . '_cron_interval';
add_action( $this->cron_hook_identifier, array( $this, 'handle_cron_healthcheck' ) );
add_filter( 'cron_schedules', array( $this, 'schedule_cron_healthcheck' ) );
// Ensure dispatch query args included extra data.
add_filter( $this->identifier . '_query_args', array( $this, 'filter_dispatch_query_args' ) );
}
/**
* Schedule the cron healthcheck and dispatch an async request to start processing the queue.
*
* @access public
* @return array|WP_Error|false HTTP Response array, WP_Error on failure, or false if not attempted.
*/
public function dispatch() {
if ( $this->is_processing() ) {
// Process already running.
return false;
}
/**
* Filter fired before background process dispatches its next process.
*
* @param bool $cancel Should the dispatch be cancelled? Default false.
* @param string $chain_id The background process chain ID.
*/
$cancel = apply_filters( $this->identifier . '_pre_dispatch', false, $this->get_chain_id() );
if ( $cancel ) {
return false;
}
// Schedule the cron healthcheck.
$this->schedule_event();
// Perform remote post.
return parent::dispatch();
}
/**
* Push to the queue.
*
* Note, save must be called in order to persist queued items to a batch for processing.
*
* @param mixed $data Data.
*
* @return $this
*/
public function push_to_queue( $data ) {
$this->data[] = $data;
return $this;
}
/**
* Save the queued items for future processing.
*
* @return $this
*/
public function save() {
$key = $this->generate_key();
if ( ! empty( $this->data ) ) {
update_site_option( $key, $this->data );
}
// Clean out data so that new data isn't prepended with closed session's data.
$this->data = array();
return $this;
}
/**
* Update a batch's queued items.
*
* @param string $key Key.
* @param array $data Data.
*
* @return $this
*/
public function update( $key, $data ) {
if ( ! empty( $data ) ) {
update_site_option( $key, $data );
}
return $this;
}
/**
* Delete a batch of queued items.
*
* @param string $key Key.
*
* @return $this
*/
public function delete( $key ) {
delete_site_option( $key );
return $this;
}
/**
* Delete entire job queue.
*/
public function delete_all() {
$batches = $this->get_batches();
foreach ( $batches as $batch ) {
$this->delete( $batch->key );
}
delete_site_option( $this->get_status_key() );
$this->cancelled();
}
/**
* Cancel job on next batch.
*/
public function cancel() {
update_site_option( $this->get_status_key(), self::STATUS_CANCELLED );
// Just in case the job was paused at the time.
$this->dispatch();
}
/**
* Has the process been cancelled?
*
* @return bool
*/
public function is_cancelled() {
return $this->get_status() === self::STATUS_CANCELLED;
}
/**
* Called when background process has been cancelled.
*/
protected function cancelled() {
do_action( $this->identifier . '_cancelled', $this->get_chain_id() );
}
/**
* Pause job on next batch.
*/
public function pause() {
update_site_option( $this->get_status_key(), self::STATUS_PAUSED );
}
/**
* Has the process been paused?
*
* @return bool
*/
public function is_paused() {
return $this->get_status() === self::STATUS_PAUSED;
}
/**
* Called when background process has been paused.
*/
protected function paused() {
do_action( $this->identifier . '_paused', $this->get_chain_id() );
}
/**
* Resume job.
*/
public function resume() {
delete_site_option( $this->get_status_key() );
$this->schedule_event();
$this->dispatch();
$this->resumed();
}
/**
* Called when background process has been resumed.
*/
protected function resumed() {
do_action( $this->identifier . '_resumed', $this->get_chain_id() );
}
/**
* Is queued?
*
* @return bool
*/
public function is_queued() {
return ! $this->is_queue_empty();
}
/**
* Is the tool currently active, e.g. starting, working, paused or cleaning up?
*
* @return bool
*/
public function is_active() {
return $this->is_queued() || $this->is_processing() || $this->is_paused() || $this->is_cancelled();
}
/**
* Generate key for a batch.
*
* Generates a unique key based on microtime. Queue items are
* given a unique key so that they can be merged upon save.
*
* @param int $length Optional max length to trim key to, defaults to 64 characters.
* @param string $key Optional string to append to identifier before hash, defaults to "batch".
*
* @return string
*/
protected function generate_key( $length = 64, $key = 'batch' ) {
$unique = md5( microtime() . wp_rand() );
$prepend = $this->identifier . '_' . $key;
if( is_multisite() ){
$site_id = get_current_blog_id();
$prepend .= '_' . $site_id;
}
$prepend .= '_';
return substr( $prepend . $unique, 0, $length );
}
/**
* Get the status key.
*
* @return string
*/
protected function get_status_key() {
return $this->identifier . '_status';
}
/**
* Get the status value for the process.
*
* @return int
*/
protected function get_status() {
global $wpdb;
if ( is_multisite() ) {
$status = $wpdb->get_var(
$wpdb->prepare(
"SELECT meta_value FROM $wpdb->sitemeta WHERE meta_key = %s AND site_id = %d LIMIT 1",
$this->get_status_key(),
get_current_network_id()
)
);
} else {
$status = $wpdb->get_var(
$wpdb->prepare(
"SELECT option_value FROM $wpdb->options WHERE option_name = %s LIMIT 1",
$this->get_status_key()
)
);
}
return absint( $status );
}
/**
* Maybe process a batch of queued items.
*
* Checks whether data exists within the queue and that
* the process is not already running.
*/
public function maybe_handle() {
// Don't lock up other requests while processing.
session_write_close();
check_ajax_referer( $this->identifier, 'nonce' );
// Background process already running.
if ( $this->is_processing() ) {
return $this->maybe_wp_die();
}
// Cancel requested.
if ( $this->is_cancelled() ) {
$this->clear_scheduled_event();
$this->delete_all();
return $this->maybe_wp_die();
}
// Pause requested.
if ( $this->is_paused() ) {
$this->clear_scheduled_event();
$this->paused();
return $this->maybe_wp_die();
}
// No data to process.
if ( $this->is_queue_empty() ) {
return $this->maybe_wp_die();
}
$this->handle();
return $this->maybe_wp_die();
}
/**
* Is queue empty?
*
* @return bool
*/
protected function is_queue_empty() {
return empty( $this->get_batch() );
}
/**
* Is process running?
*
* Check whether the current process is already running
* in a background process.
*
* @return bool
*
* @deprecated 1.1.0 Superseded.
* @see is_processing()
*/
protected function is_process_running() {
return $this->is_processing();
}
/**
* Is the background process currently running?
*
* @return bool
*/
public function is_processing() {
if ( get_site_transient( $this->identifier . '_process_lock' ) ) {
// Process already running.
return true;
}
return false;
}
/**
* Lock process.
*
* Lock the process so that multiple instances can't run simultaneously.
* Override if applicable, but the duration should be greater than that
* defined in the time_exceeded() method.
*
* @param bool $reset_start_time Optional, default true.
*/
public function lock_process( $reset_start_time = true ) {
if ( $reset_start_time ) {
$this->start_time = time(); // Set start time of current process.
}
$lock_duration = ( property_exists( $this, 'queue_lock_time' ) ) ? $this->queue_lock_time : 60; // 1 minute
$lock_duration = apply_filters( $this->identifier . '_queue_lock_time', $lock_duration );
$microtime = microtime();
$locked = set_site_transient( $this->identifier . '_process_lock', $microtime, $lock_duration );
/**
* Action to note whether the background process managed to create its lock.
*
* The lock is used to signify that a process is running a task and no other
* process should be allowed to run the same task until the lock is released.
*
* @param bool $locked Whether the lock was successfully created.
* @param string $microtime Microtime string value used for the lock.
* @param int $lock_duration Max number of seconds that the lock will live for.
* @param string $chain_id Current background process chain ID.
*/
do_action(
$this->identifier . '_process_locked',
$locked,
$microtime,
$lock_duration,
$this->get_chain_id()
);
}
/**
* Unlock process.
*
* Unlock the process so that other instances can spawn.
*
* @return $this
*/
protected function unlock_process() {
$unlocked = delete_site_transient( $this->identifier . '_process_lock' );
/**
* Action to note whether the background process managed to release its lock.
*
* The lock is used to signify that a process is running a task and no other
* process should be allowed to run the same task until the lock is released.
*
* @param bool $unlocked Whether the lock was released.
* @param string $chain_id Current background process chain ID.
*/
do_action( $this->identifier . '_process_unlocked', $unlocked, $this->get_chain_id() );
return $this;
}
/**
* Get batch.
*
* @param int $for_site_id Get batch for a specific Site ID (multisite)
* @return \stdClass Return the first batch of queued items.
*/
protected function get_batch($for_site_id = null) {
return array_reduce(
$this->get_batches( 1, $for_site_id ),
static function ( $carry, $batch ) {
return $batch;
},
array()
);
}
/**
* Get batches.
*
* @param int $limit Number of batches to return, defaults to all.
* @param int $for_site_id Get batches for a specific Site ID (multisite)
* @return array of stdClass
*/
public function get_batches( $limit = 0, $for_site_id = null ) {
global $wpdb;
if ( empty( $limit ) || ! is_int( $limit ) ) {
$limit = 0;
}
$table = $wpdb->options;
$column = 'option_name';
$key_column = 'option_id';
$value_column = 'option_value';
if ( is_multisite() ) {
$table = $wpdb->sitemeta;
$column = 'meta_key';
$key_column = 'meta_id';
$value_column = 'meta_value';
}
if( !is_null( $for_site_id ) ) {
$key = $wpdb->esc_like( $this->identifier . '_batch_' . $for_site_id ) . '%';
} else {
$key = $wpdb->esc_like( $this->identifier . '_batch_' ) . '%';
}
$sql = '
SELECT *
FROM ' . $table . '
WHERE ' . $column . ' LIKE %s
ORDER BY ' . $key_column . ' ASC
';
$args = array( $key );
if ( ! empty( $limit ) ) {
$sql .= ' LIMIT %d';
$args[] = $limit;
}
$items = $wpdb->get_results(
$wpdb->prepare(
$sql, // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
$args
)
);
$batches = array();
if ( ! empty( $items ) ) {
$allowed_classes = $this->allowed_batch_data_classes;
$batches = array_map(
static function ( $item ) use ( $column, $value_column, $allowed_classes ) {
$batch = new \stdClass();
$batch->key = $item->{$column};
if( is_multisite() ) {
$batch->site_id = static::extract_site_id_from_column_name($item->{$column});
}
$batch->data = static::maybe_unserialize( $item->{$value_column}, $allowed_classes );
return $batch;
},
$items
);
}
return $batches;
}
/**
* Extract the site ID from the database column name when in a multisite environment
*
* @param $column_name
* @return int|null
*/
protected static function extract_site_id_from_column_name($column_name ) {
if ( preg_match( '/_batch_(\d+)_/', $column_name, $matches ) ) {
return intval( $matches[1] );
}
return null;
}
/**
* Handle a dispatched request.
*
* Pass each queue item to the task handler, while remaining
* within server memory and time limit constraints.
*/
protected function handle() {
$this->lock_process();
/**
* Number of seconds to sleep between batches. Defaults to 0 seconds, minimum 0.
*
* @param int $seconds
*/
$throttle_seconds = max(
$this->seconds_between_batches,
apply_filters(
$this->identifier . '_seconds_between_batches',
apply_filters(
$this->prefix . '_seconds_between_batches',
0
)
)
);
do {
$batch = $this->get_batch();
if( is_multisite() && !is_null( $batch->site_id ) && $batch->site_id !== get_current_blog_id() ) {
//Do not try to run a batch for a site that doesn't exist (anymore)
if ( ! get_site( $batch->site_id ) ) {
$this->delete( $batch->key );
continue;
}
switch_to_blog( $batch->site_id );
$this->switched_to_blog = true;
}
foreach ( $batch->data as $key => $value ) {
$task = $this->task( $value );
if ( false !== $task ) {
$batch->data[ $key ] = $task;
} else {
unset( $batch->data[ $key ] );
}
// Keep the batch up to date while processing it.
if ( ! empty( $batch->data ) ) {
$this->update( $batch->key, $batch->data );
}
// Let the server breathe a little.
sleep( $throttle_seconds );
// Batch limits reached, or pause or cancel requested.
if ( ! $this->should_continue() ) {
break;
}
}
// Delete current batch if fully processed.
if ( empty( $batch->data ) ) {
$this->delete( $batch->key );
}
if( $this->switched_to_blog ) {
restore_current_blog();
}
// Let the server breathe a little.
sleep( $throttle_seconds );
} while ( ! $this->is_queue_empty() && $this->should_continue() );
$this->unlock_process();
// Start next batch or complete process.
if ( ! $this->is_queue_empty() ) {
$this->dispatch();
} else {
$this->complete();
}
return $this->maybe_wp_die();
}
/**
* Memory exceeded?
*
* Ensures the batch process never exceeds 90%
* of the maximum WordPress memory.
*
* @return bool
*/
protected function memory_exceeded() {
$memory_limit = $this->get_memory_limit() * 0.9; // 90% of max memory
$current_memory = memory_get_usage( true );
$return = false;
if ( $current_memory >= $memory_limit ) {
$return = true;
}
return apply_filters( $this->identifier . '_memory_exceeded', $return );
}
/**
* Get memory limit in bytes.
*
* @return int
*/
protected function get_memory_limit() {
if ( function_exists( 'ini_get' ) ) {
$memory_limit = ini_get( 'memory_limit' );
} else {
// Sensible default.
$memory_limit = '128M';
}
if ( ! $memory_limit || -1 === intval( $memory_limit ) ) {
// Unlimited, set to 32GB.
$memory_limit = '32000M';
}
return wp_convert_hr_to_bytes( $memory_limit );
}
/**
* Time limit exceeded?
*
* Ensures the batch never exceeds a sensible time limit.
* A timeout limit of 30s is common on shared hosting.
*
* @return bool
*/
protected function time_exceeded() {
$finish = $this->start_time + apply_filters( $this->identifier . '_default_time_limit', 20 ); // 20 seconds
$return = false;
if ( time() >= $finish ) {
$return = true;
}
return apply_filters( $this->identifier . '_time_exceeded', $return );
}
/**
* Complete processing.
*
* Override if applicable, but ensure that the below actions are
* performed, or, call parent::complete().
*/
protected function complete() {
delete_site_option( $this->get_status_key() );
// Remove the cron healthcheck job from the cron schedule.
$this->clear_scheduled_event();
$this->completed();
}
/**
* Called when background process has completed.
*/
protected function completed() {
do_action( $this->identifier . '_completed', $this->get_chain_id() );
}
/**
* Get the cron healthcheck interval in minutes.
*
* Default is 5 minutes, minimum is 1 minute.
*
* @return int
*/
public function get_cron_interval() {
$interval = 5;
if ( property_exists( $this, 'cron_interval' ) ) {
$interval = $this->cron_interval;
}
$interval = apply_filters( $this->cron_interval_identifier, $interval );
return is_int( $interval ) && 0 < $interval ? $interval : 5;
}
/**
* Schedule the cron healthcheck job.
*
* @access public
*
* @param mixed $schedules Schedules.
*
* @return mixed
*/
public function schedule_cron_healthcheck( $schedules ) {
$interval = $this->get_cron_interval();
if ( 1 === $interval ) {
$display = __( 'Every Minute' );
} else {
$display = sprintf( __( 'Every %d Minutes' ), $interval );
}
// Adds an "Every NNN Minute(s)" schedule to the existing cron schedules.
$schedules[ $this->cron_interval_identifier ] = array(
'interval' => MINUTE_IN_SECONDS * $interval,
'display' => $display,
);
return $schedules;
}
/**
* Handle cron healthcheck event.
*
* Restart the background process if not already running
* and data exists in the queue.
*/
public function handle_cron_healthcheck() {
if ( $this->is_processing() ) {
// Background process already running.
exit;
}
if ( $this->is_queue_empty() ) {
// No data to process.
$this->clear_scheduled_event();
exit;
}
$this->dispatch();
}
/**
* Schedule the cron healthcheck event.
*/
protected function schedule_event() {
if ( ! wp_next_scheduled( $this->cron_hook_identifier ) ) {
wp_schedule_event(
time() + ( $this->get_cron_interval() * MINUTE_IN_SECONDS ),
$this->cron_interval_identifier,
$this->cron_hook_identifier
);
}
}
/**
* Clear scheduled cron healthcheck event.
*/
protected function clear_scheduled_event() {
$timestamp = wp_next_scheduled( $this->cron_hook_identifier );
if ( $timestamp ) {
wp_unschedule_event( $timestamp, $this->cron_hook_identifier );
}
}
/**
* Cancel the background process.
*
* Stop processing queue items, clear cron job and delete batch.
*
* @deprecated 1.1.0 Superseded.
* @see cancel()
*/
public function cancel_process() {
$this->cancel();
}
/**
* Perform task with queued item.
*
* Override this method to perform any actions required on each
* queue item. Return the modified item for further processing
* in the next pass through. Or, return false to remove the
* item from the queue.
*
* @param mixed $item Queue item to iterate over.
*
* @return mixed
*/
abstract protected function task( $item );
/**
* Maybe unserialize data, but not if an object.
*
* @param mixed $data Data to be unserialized.
* @param bool|array $allowed_classes Array of class names that can be unserialized.
*
* @return mixed
*/
protected static function maybe_unserialize( $data, $allowed_classes ) {
if ( is_serialized( $data ) ) {
$options = array();
if ( is_bool( $allowed_classes ) || is_array( $allowed_classes ) ) {
$options['allowed_classes'] = $allowed_classes;
}
return @unserialize( $data, $options ); // @phpcs:ignore
}
return $data;
}
/**
* Should any processing continue?
*
* @return bool
*/
public function should_continue() {
/**
* Filter whether the current background process should continue running the task
* if there is data to be processed.
*
* If the processing time or memory limits have been exceeded, the value will be false.
* If pause or cancel have been requested, the value will be false.
*
* It is very unlikely that you would want to override a false value with true.
*
* If false is returned here, it does not necessarily mean background processing is
* complete. If there is batch data still to be processed and pause or cancel have not
* been requested, it simply means this background process should spawn a new process
* for the chain to continue processing and then close itself down.
*
* @param bool $continue Should the current process continue processing the task?
* @param string $chain_id The current background process chain's ID.
*
* @return bool
*/
return apply_filters(
$this->identifier . '_should_continue',
! ( $this->time_exceeded() || $this->memory_exceeded() || $this->is_paused() || $this->is_cancelled() ),
$this->get_chain_id()
);
}
/**
* Get the string used to identify this type of background process.
*
* @return string
*/
public function get_identifier() {
return $this->identifier;
}
/**
* Return the current background process chain's ID.
*
* If the chain's ID hasn't been set before this function is first used,
* and hasn't been passed as a query arg during dispatch,
* the chain ID will be generated before being returned.
*
* @return string
*/
public function get_chain_id() {
if ( empty( $this->chain_id )
&& wp_doing_ajax()
&& isset( $_REQUEST['action'] )
&& $_REQUEST['action'] === $this->identifier ) {
check_ajax_referer( $this->identifier, 'nonce' );
if ( ! empty( $_GET[ $this->get_chain_id_arg_name() ] ) ) {
$chain_id = sanitize_key( $_GET[ $this->get_chain_id_arg_name() ] );
if ( wp_is_uuid( $chain_id ) ) {
$this->chain_id = $chain_id;
return $this->chain_id;
}
}
}
if ( empty( $this->chain_id ) ) {
$this->chain_id = wp_generate_uuid4();
}
return $this->chain_id;
}
/**
* Filters the query arguments used during an async request.
*
* @param array $args Current query args.
*
* @return array
*/
public function filter_dispatch_query_args( $args ) {
$args[ $this->get_chain_id_arg_name() ] = $this->get_chain_id();
return $args;
}
/**
* Get the query arg name used for passing the chain ID to new processes.
*
* @return string
*/
private function get_chain_id_arg_name() {
static $chain_id_arg_name;
if ( ! empty( $chain_id_arg_name ) ) {
return $chain_id_arg_name;
}
/**
* Filter the query arg name used for passing the chain ID to new processes.
*
* If you encounter problems with using the default query arg name, you can
* change it with this filter.
*
* @param string $chain_id_arg_name Default "chain_id".
*
* @return string
*/
$chain_id_arg_name = apply_filters( $this->identifier . '_chain_id_arg_name', self::CHAIN_ID_ARG_NAME );
if ( ! is_string( $chain_id_arg_name ) || empty( $chain_id_arg_name ) ) {
$chain_id_arg_name = self::CHAIN_ID_ARG_NAME;
}
return $chain_id_arg_name;
}
}
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