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<?php /** * Class Tribe__Meta__Chunker * * Chunks large meta to avoid killing the database in queries. * * Databases can have a `max_allowed_packet` value set as low as 1M; we often need to store large blobs of data way * over that and doing so would kill the database ("MySQL server has gone away"...); registering a meta to be chunked * if needed avoids that. * * Example usage: * * $chunker = tribe( 'chunker' ); * $chunker->register_for_chunking( $post_id, 'my_meta_key' ); * * // ... some code later... * * // data will be transparently chunked if needed... * update_meta( $post_id, 'my_meta_key', $some_looooooooooong_string ); * * // ...and glued back together when reading * get_post_meta( $post_id, 'my_meta_key', true ); * * By default the Chunker supports the `post` post type only, filter the `tribe_meta_chunker_post_types` to add yours: * * add_filter( 'tribe_meta_chunker_post_types`, 'my_chunkable_post_types' ); * function my_chunkable_post_types( $post_types ) { * $post_types[] = 'book'; * * return $post_types; * } * * or filter the `tribe_meta_chunker_post_types` filter. */ class Tribe__Meta__Chunker { /** * @var string The key used to cache the class results in the WordPress object cache. */ protected $cache_group = 'post_meta'; /** * @var string */ protected $chunked_keys_option_name = '_tribe_chunker_chunked_keys'; /** * @var array The cache that will store chunks to avoid middleware operations from fetching the database. */ protected $chunks_cache = null; /** * @var array The cache that will store the IDs of the posts that have at least one meta key registered * for chunking. */ protected $post_ids_cache = null; /** * @var string The separator that's used to mark the start of each chunk. */ protected $chunk_separator = '{{{TCSEP}}}'; /** * @var array The post types supported by the Chunker. */ protected $post_types = []; /** * @var int The filter priority at which Chunker will operate on meta CRUD operations. */ protected $filter_priority = - 1; /** * @var string The meta key prefix applied ot any Chunker related post meta. */ protected $meta_key_prefix = '_tribe_chunker_'; /** * @var int The largest size allowed by the Chunker. */ protected $max_chunk_size; /** * Hooks the chunker on metadata operations for each supported post types. * * When changing post types unhook and rehook it like: * * $chunker = tribe( 'chunker' ); * $chunker->set_post_types( array_merge( $my_post_types, $chunker->get_post_types() ); * $chunker->unhook(); * $chunker->hook(); */ public function hook() { if ( empty( $this->post_types ) ) { return; } add_filter( 'update_post_metadata', [ $this, 'filter_update_metadata' ], $this->filter_priority, 4 ); add_filter( 'delete_post_metadata', [ $this, 'filter_delete_metadata' ], $this->filter_priority, 3 ); add_filter( 'add_post_metadata', [ $this, 'filter_add_metadata' ], $this->filter_priority, 4 ); add_filter( 'get_post_metadata', [ $this, 'filter_get_metadata' ], $this->filter_priority, 4 ); add_action( 'deleted_post', [ $this, 'remove_post_entry' ] ); } /** * Primes the chunked cache. * * This will just fetch the keys for the supported post types, not the values. * * @param bool $force Whether the cache should be reprimed even if already primed. */ public function prime_chunks_cache( $force = false ) { if ( false === $force && null !== $this->chunks_cache ) { return; } $this->chunks_cache = []; $this->post_ids_cache = []; $chunked_keys = get_option( $this->chunked_keys_option_name ); if ( empty( $chunked_keys ) ) { return; } foreach ( $chunked_keys as $post_id => $keys ) { if ( ! is_array( $keys ) || empty( $keys ) ) { continue; } $this->post_ids_cache[] = $post_id; foreach ( $keys as $key ) { $this->chunks_cache[ $this->get_key( $post_id, $key ) ] = null; } } } /** * Gets the key used to identify a post ID and meta key in the chunks cache. * * @param int $post_id * @param string $meta_key * @return string */ public function get_key( $post_id, $meta_key ) { return "{$post_id}::{$meta_key}"; } /** * Register a post ID and meta key to be chunked if needed. * * @param int $post_id * @param string $meta_key * * @return bool `false` if the post type is not supported, `true` otherwise */ public function register_chunking_for( $post_id, $meta_key ) { if ( ! $this->is_supported_post_type( $post_id ) ) { return false; } $this->tag_as_chunkable( $post_id, $meta_key ); return true; } /** * Whether a post type is supported or not. * * @param int $object_id * * @return bool */ protected function is_supported_post_type( $object_id ) { $post = get_post( $object_id ); if ( empty( $post ) || ! in_array( $post->post_type, $this->post_types ) ) { return false; } return true; } /** * Tags a post ID and meta key couple as "chunkable" if needed. * * @param $post_id * @param $meta_key */ protected function tag_as_chunkable( $post_id, $meta_key ) { $key = $this->get_key( $post_id, $meta_key ); $this->prime_chunks_cache(); if ( ! array_key_exists( $key, $this->chunks_cache ) ) { $this->chunks_cache[ $key ] = null; } $this->post_ids_cache[] = $post_id; $option = (array) get_option( $this->chunked_keys_option_name ); if ( ! isset( $option[ $post_id ] ) ) { $option[ $post_id ] = [ $meta_key ]; } else { $option[ $post_id ][] = $meta_key; } update_option( $this->chunked_keys_option_name, array_filter( $option ), true ); } /** * Returns the meta key used to indicate if a meta key for a post is marked as chunkable. * * @param string $meta_key * * @return string */ public function get_chunkable_meta_key( $meta_key ) { return $this->meta_key_prefix . $meta_key; } /** * Filters the add operations. * * Due to how the system works no more than one chunked entry can be stored. * * @param mixed $check * @param int $object_id * @param string $meta_key * @param string $meta_value * * @see add_metadata() * * @return bool */ public function filter_add_metadata( $check, $object_id, $meta_key, $meta_value ) { return $this->filter_update_metadata( $check, $object_id, $meta_key, $meta_value ); } /** * Filters the updated operations. * * @param mixed $check * @param int $object_id * @param string $meta_key * @param string $meta_value * * @see update_metadata() * * @return bool */ public function filter_update_metadata( $check, $object_id, $meta_key, $meta_value ) { if ( ! $this->applies( $object_id, $meta_key ) ) { return $check; } /** * Filters the chunked meta update operation. * * Returning a non null value here will make the function return that value immediately. * * @param mixed $updated * @param int $object_id The post ID * @param string $meta_key * @param mixed $meta_value * * @since 4.5.6 */ $updated = apply_filters( 'tribe_meta_chunker_update_meta', null, $object_id, $meta_key, $meta_value ); if ( null !== $updated ) { return $updated; } $this->delete_chunks( $object_id, $meta_key ); $this->remove_checksum_for( $object_id, $meta_key ); wp_cache_delete( $object_id, $this->cache_group ); if ( $this->should_be_chunked( $object_id, $meta_key, $meta_value ) ) { $this->insert_chunks( $object_id, $meta_key ); return true; } else { $this->cache_delete( $object_id, $meta_key ); $this->insert_meta( $object_id, $meta_key, $meta_value ); return true; } return $check; } /** * Whether the chunker should operate on this post ID and meta key couple or not. * * @param int $object_id * @param string $meta_key * * @return bool */ protected function applies( $object_id, $meta_key ) { $applies = ! $this->is_chunker_logic_meta_key( $meta_key ) && $this->is_supported_post_type( $object_id ) && $this->is_chunkable( $object_id, $meta_key ); /** * Filters whether the meta chunker will apply to a post ID and meta key or not. * * The `$meta_key` parameter might be empty. * * @param bool $applies * @param int $object_id * @param string $meta_key * * @since 4.5.6 */ return apply_filters( 'tribe_meta_chunker_applies', $applies, $object_id, $meta_key ); } /** * Whether the meta key is one used by the chunker to keep track of its operations or not. * * @param string $meta_key * * @return bool */ protected function is_chunker_logic_meta_key( $meta_key ) { if ( ! is_string( $meta_key ) ) { return false; } return 0 === strpos( $meta_key, $this->meta_key_prefix ); } /** * Whether a post ID and meta key couple is registered as chunkable or not. * * If no meta key is passed then the function will check if there is at least * one meta key registered for chunking for the specified post ID. * * @param int $post_id * @param string $meta_key * * @return bool */ public function is_chunkable( $post_id, $meta_key = null ) { $this->prime_chunks_cache(); return ! empty( $meta_key ) ? array_key_exists( $this->get_key( $post_id, $meta_key ), $this->chunks_cache ) : in_array( $post_id, $this->post_ids_cache ); } /** * Deletes all the chunks for a post ID and meta key couple. * * @param int $object_id * @param string $meta_key */ protected function delete_chunks( $object_id, $meta_key ) { /** @var wpdb $wpdb */ global $wpdb; $chunk_meta_key = $this->get_chunk_meta_key( $meta_key ); $delete = "DELETE FROM {$wpdb->postmeta} WHERE (meta_key = %s OR meta_key = %s) AND post_id = %d"; $wpdb->query( $wpdb->prepare( $delete, $chunk_meta_key, $meta_key, $object_id ) ); } /** * Returns the meta key used to indicate a chunk for a meta key. * * @param string $meta_key * * @return string */ public function get_chunk_meta_key( $meta_key ) { return $this->get_chunkable_meta_key( $meta_key ) . '_chunk'; } /** * Removes the checksum used to verify the integrity of the chunked values. * * @param int $object_id * @param string $meta_key */ protected function remove_checksum_for( $object_id, $meta_key ) { /** @var wpdb $wpdb */ global $wpdb; $data = [ 'post_id' => $object_id, 'meta_key' => $this->get_checksum_key( $meta_key ), ]; $wpdb->delete( $wpdb->postmeta, $data ); } /** * Returns the meta_key used to store the chunked meta checksum for a specified meta key. * * @param string $meta_key * * @return string */ public function get_checksum_key( $meta_key ) { return $this->meta_key_prefix . $meta_key . '_checksum'; } /** * Whether a value should be chunked or not. * * @param int $post_id * @param string $meta_key * @param mixed $meta_value * * @return bool */ public function should_be_chunked( $post_id, $meta_key, $meta_value ) { $should_be_chunked = false; $max_allowed_packet = $this->get_max_chunk_size(); $serialized = maybe_serialize( $meta_value ); $byte_size = $this->get_byte_size( $serialized ); $this->prime_chunks_cache(); // we use .8 and not 1 to allow for MySQL instructions to use 20% of the string size if ( $byte_size > .8 * $max_allowed_packet ) { $chunk_size = ceil( $max_allowed_packet * 0.75 ); $key = $this->get_key( $post_id, $meta_key ); $this->chunks_cache[ $key ] = $this->prefix_chunks( $this->chunk( $serialized, $chunk_size ) ); $should_be_chunked = true; } return $should_be_chunked; } /** * Returns the max chunk size in bytes. * * @return array|int|null|object */ public function get_max_chunk_size() { if ( ! empty( $this->max_chunk_size ) ) { return $this->max_chunk_size; } $max_size = tribe( 'db' )->get_max_allowed_packet_size(); /** * Filters the max size of the of the chunks in bytes. * * @param int $max_size By default the `max_allowed_packet` from the database. */ $this->max_chunk_size = apply_filters( 'tribe_meta_chunker_max_size', $max_size ); return $max_size; } /** * Sets the max chunk size. * * @param int $max_chunk_size The max chunk size in bytes. */ public function set_max_chunk_size( $max_chunk_size ) { $this->max_chunk_size = $max_chunk_size; } /** * Gets the size in bytes of something. * * @param mixed $data * * @return int */ public function get_byte_size( $data ) { return strlen( utf8_decode( maybe_serialize( $data ) ) ); } /** * Prefixes each chunk with a sequence number. * * @param array $chunks * * @return array An array of chunks each prefixed with sequence number. */ protected function prefix_chunks( array $chunks ) { $count = count( $chunks ); $prefixed = []; for ( $i = 0; $i < $count; $i ++ ) { $prefixed[] = "{$i}{$this->chunk_separator}{$chunks[$i]}"; } return $prefixed; } /** * Chunks a string. * * The chunks are not prefixed! * * @param string $serialized * @param int $chunk_size * * @return array An array of unprefixed chunks. */ protected function chunk( $serialized, $chunk_size ) { $sep = $this->chunk_separator; $chunks = array_filter( explode( $sep, chunk_split( $serialized, $chunk_size, $sep ) ) ); return $chunks; } /** * Inserts the chunks for a post ID and meta key couple in the database. * * The chunks are read from the array cache. * * @param int $object_id * @param string $meta_key */ protected function insert_chunks( $object_id, $meta_key ) { /** @var wpdb $wpdb */ global $wpdb; $this->prime_chunks_cache(); $key = $this->get_key( $object_id, $meta_key ); $chunks = $this->chunks_cache[ $key ]; $chunk_meta_key = $this->get_chunk_meta_key( $meta_key ); $this->insert_meta( $object_id, $meta_key, $chunks[0] ); foreach ( $chunks as $chunk ) { $wpdb->insert( $wpdb->postmeta, [ 'post_id' => $object_id, 'meta_key' => $chunk_meta_key, 'meta_value' => $chunk, ] ); } $glued = $this->glue_chunks( $this->get_chunks_for( $object_id, $meta_key ) ); $checksum_key = $this->get_checksum_key( $meta_key ); $wpdb->delete( $wpdb->postmeta, [ 'post_id' => $object_id, 'meta_key' => $checksum_key ] ); $wpdb->insert( $wpdb->postmeta, [ 'post_id' => $object_id, 'meta_key' => $checksum_key, 'meta_value' => md5( $glued ), ] ); } /** * Inserts a meta value in the database. * * Convenience method to avoid infinite loop in hooks. * * @param int $object_id * @param string $meta_key * @param mixed $meta_value */ protected function insert_meta( $object_id, $meta_key, $meta_value ) { /** @var wpdb $wpdb */ global $wpdb; $data = [ 'post_id' => $object_id, 'meta_key' => $meta_key, 'meta_value' => maybe_serialize( $meta_value ), ]; $wpdb->insert( $wpdb->postmeta, $data ); } /** * Glues the provided chunks. * * This method is sequence aware and should be used with what the `get_chunks_for` method returns. * * @param array $chunks * * @return string * * @see Tribe__Meta__Chunker::get_chunks_for() */ public function glue_chunks( array $chunks ) { $ordered_chunks = []; foreach ( $chunks as $chunk ) { preg_match( '/(\\d+)' . preg_quote( $this->chunk_separator ) . '(.*)/', $chunk, $matches ); $ordered_chunks[ $matches[1] ] = $matches[2]; } ksort( $ordered_chunks ); return implode( '', array_values( $ordered_chunks ) ); } /** * Returns the chunks stored in the database for a post ID and meta key couple. * * The chunks are returned as they are with prefix. * * @param int $object_id * @param string $meta_key * * @return array|mixed */ public function get_chunks_for( $object_id, $meta_key ) { $key = $this->get_key( $object_id, $meta_key ); $this->prime_chunks_cache(); if ( ! empty( $this->chunks_cache[ $key ] ) ) { return $this->chunks_cache[ $key ]; } /** @var wpdb $wpdb */ global $wpdb; $chunk_meta_key = $this->get_chunk_meta_key( $meta_key ); $meta_ids = $wpdb->get_col( $wpdb->prepare( "SELECT meta_id FROM {$wpdb->postmeta} WHERE post_id = %d AND meta_key = %s", $object_id, $chunk_meta_key ) ); $meta_values = []; foreach ( $meta_ids as $meta_id ) { $query = $wpdb->prepare( "SELECT meta_value FROM {$wpdb->postmeta} WHERE meta_id = %d", $meta_id ); $meta_values[] = $wpdb->get_var( $query ); } if ( ! empty( $meta_values ) ) { $this->chunks_cache[ $this->get_key( $object_id, $meta_key ) ] = $meta_values; } else { $this->chunks_cache[ $this->get_key( $object_id, $meta_key ) ] = null; } return $meta_values; } /** * Resets a post ID and meta key couple cache. * * @param int $object_id * @param string $meta_key */ protected function cache_delete( $object_id, $meta_key ) { $key = $this->get_key( $object_id, $meta_key ); $this->prime_chunks_cache(); if ( isset( $this->chunks_cache[ $key ] ) ) { $this->chunks_cache[ $key ] = null; } } /** * Filters the delete operations. * * @param mixed $check * @param int $object_id * @param string $meta_key * * @return bool * * @see delete_metadata() */ public function filter_delete_metadata( $check, $object_id, $meta_key ) { if ( ! $this->applies( $object_id, $meta_key ) ) { return $check; } /** * Filters the value returned when deleting a specific meta for a post. * * Returning a non null value here will make the function return that value immediately. * * @param mixed $deleted * @param int $object_id The post ID * @param string $meta_key The requested meta key * * @since 4.5.6 */ $deleted = apply_filters( 'tribe_meta_chunker_delete_meta', null, $object_id, $meta_key ); if ( null !== $deleted ) { return $deleted; } $has_chunked_meta = $this->is_chunked( $object_id, $meta_key ); if ( ! $has_chunked_meta ) { return $check; } $this->cache_delete( $object_id, $meta_key ); $this->delete_chunks( $object_id, $meta_key ); wp_cache_delete( $object_id, $this->cache_group ); return true; } /** * Whether a post ID and meta key couple has chunked meta or not. * * @param int $object_id * @param string $meta_key * @param bool $check_db Do verify the chunking state on the database. * * @return mixed */ public function is_chunked( $object_id, $meta_key, $check_db = false ) { $key = $this->get_key( $object_id, $meta_key ); $this->prime_chunks_cache(); $chunked_in_cache = array_key_exists( $key, $this->chunks_cache ) && is_array( $this->chunks_cache[ $key ] ); return $chunked_in_cache; } /** * Returns the checksum for the stored meta key to spot meta value corruption malforming. * * @param int $object_id * @param string $meta_key * * @return string */ public function get_checksum_for( $object_id, $meta_key ) { /** @var wpdb $wpdb */ global $wpdb; $query = "SELECT meta_value FROM {$wpdb->postmeta} WHERE post_id = %d AND meta_key = %s"; $checksum = $wpdb->get_var( $wpdb->prepare( $query, $object_id, $this->get_checksum_key( $meta_key ) ) ); return ! empty( $checksum ) ? $checksum : ''; } /** * Handles the object destruction cycle to leave no traces behind. */ public function __destruct() { $this->unhook(); } /** * Unhooks the Chunker from the metadata operations. */ public function unhook() { remove_filter( 'update_post_metadata', [ $this, 'filter_update_metadata' ], $this->filter_priority ); remove_filter( 'delete_post_metadata', [ $this, 'filter_delete_metadata' ], $this->filter_priority ); remove_filter( 'add_post_metadata', [ $this, 'filter_add_metadata' ], $this->filter_priority ); remove_filter( 'get_post_metadata', [ $this, 'filter_get_metadata' ], $this->filter_priority ); remove_action( 'deleted_post', [ $this, 'remove_post_entry' ] ); } /** * Filters the get operations. * * @param mixed $check * @param int $object_id * @param string $meta_key * @param bool $single * * @return array|mixed * * @see get_metadata() */ public function filter_get_metadata( $check, $object_id, $meta_key, $single ) { if ( ! $this->applies( $object_id, $meta_key ) ) { return $check; } $all_meta = wp_cache_get( $object_id, $this->cache_group ); if ( ! $all_meta ) { $all_meta = $this->get_all_meta_for( $object_id ); wp_cache_set( $object_id, $all_meta, $this->cache_group ); } // getting all the meta if ( empty( $meta_key ) ) { return $all_meta; } // why not take $single into account? See condition check on the filter to understand. $meta_value = isset( $all_meta[ $meta_key ] ) ? array_map( 'maybe_unserialize', $all_meta[ $meta_key ] ) : ''; /** * Filters the value returned when getting a specific meta for a post. * * Returning a non null value here will make the function return that value immediately. * * @param mixed $meta_value * @param int $object_id The post ID * @param string $meta_key The requested meta key * * @since 4.5.6 */ $meta_value = apply_filters( 'tribe_meta_chunker_get_meta', $meta_value, $object_id, $meta_key ); if ( $single ) { return (array) $meta_value; } else { return ! empty( $meta_value ) ? $meta_value : ''; } } /** * Returns all the meta for a post ID. * * The meta includes the chunked one but not the chunker logic meta keys. * The return format is the same used by the `get_post_meta( $post_id )` function. * * @param int $object_id * * @return array An array containing all meta including the chunked one. * * @see get_post_meta() with empty `$meta_key` argument. */ public function get_all_meta_for( $object_id ) { $all_meta = $this->get_all_meta( $object_id ); if ( empty( $all_meta ) ) { return []; } $grouped = []; foreach ( $all_meta as $entry ) { if ( ! isset( $grouped[ $entry['meta_key'] ] ) ) { $grouped[ $entry['meta_key'] ] = [ $entry['meta_value'] ]; } else { $grouped[ $entry['meta_key'] ][] = $entry['meta_value']; } } $chunker_meta_keys = array_filter( array_keys( $grouped ), [ $this, 'is_chunker_logic_meta_key' ] ); if ( empty( $chunker_meta_keys ) ) { return $grouped; } $checksum_keys = array_filter( $chunker_meta_keys, [ $this, 'is_chunker_checksum_key' ] ); if ( empty( $checksum_keys ) ) { return $grouped; } $chunker_meta = array_intersect_key( $grouped, array_combine( $chunker_meta_keys, $chunker_meta_keys ) ); $normal_meta = array_diff_key( $grouped, array_combine( $chunker_meta_keys, $chunker_meta_keys ) ); foreach ( $checksum_keys as $checksum_key ) { $normal_meta_key = str_replace( [ $this->meta_key_prefix, '_checksum' ], '', $checksum_key ); $chunk_meta_key = $this->get_chunk_meta_key( $normal_meta_key ); if ( empty( $chunker_meta[ $chunk_meta_key ] ) ) { continue; } $normal_meta[ $normal_meta_key ] = [ $this->glue_chunks( $chunker_meta[ $chunk_meta_key ] ) ]; } return $normal_meta; } /** * Fetches all the meta for a post. * * @param int $object_id * * @return array|null|object */ protected function get_all_meta( $object_id ) { /** * Filters the value returned when getting all the meta for a post. * * Returning a non null value here will make the function return that value immediately. * * @param mixed $all_meta * @param int $object_id The post ID * * @since 4.5.6 */ $all_meta = apply_filters( 'tribe_meta_chunker_get_all_meta', null, $object_id ); if ( null !== $all_meta ) { return $all_meta; } /** @var wpdb $wpdb */ global $wpdb; $query = $wpdb->prepare( "SELECT meta_key, meta_value FROM {$wpdb->postmeta} WHERE post_id = %d", $object_id ); $results = $wpdb->get_results( $query, ARRAY_A ); return ! empty( $results ) && is_array( $results ) ? $results : []; } /** * Returns the post types supported by the chunker. * * @return array */ public function get_post_types() { return $this->post_types; } /** * Sets the post types the Chunker should support. * * @param array $post_types */ public function set_post_types( array $post_types = null ) { if ( null === $post_types ) { /** * Filters the chunk-able post types. * * @param array $post_types */ $this->post_types = apply_filters( 'tribe_meta_chunker_post_types', $this->post_types ); return; } $this->post_types = $post_types; } /** * Returns the name of the option that stores the keys registered for chunking for each post. * * @return string */ public function get_key_option_name() { return $this->chunked_keys_option_name; } /** * Returns the cache group used by the meta chunker. * * @return string */ public function get_cache_group() { return $this->cache_group; } /** * Asserts that a meta key is not a chunk meta key. * * @param string $meta_key * * @return bool */ protected function is_chunker_checksum_key( $meta_key ) { return preg_match( "/^{$this->meta_key_prefix}.*_checksum$/", $meta_key ); } /** * Removes the entries associated with a deleted post from the cache and the database option. * * @param int $post_id A post ID */ public function remove_post_entry( $post_id ) { $this->prime_chunks_cache(); foreach ( $this->chunks_cache as $key => $value ) { if ( 0 === strpos( $key, (string) $post_id ) ) { unset( $this->chunks_cache[ $key ] ); } } if ( ! empty( $this->chunks_cache ) ) { update_option( $this->chunked_keys_option_name, $this->chunks_cache ); } else { delete_option( $this->chunked_keys_option_name ); } } }
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