update_meta_cache( string $meta_type, string|int[] $object_ids )

Update the metadata cache for the specified objects.


Description Description


Parameters Parameters

$meta_type

(string) (Required) Type of object metadata is for (e.g., comment, post, term, or user).

$object_ids

(string|int[]) (Required) Array or comma delimited list of object IDs to update cache for.


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Return Return

(array|false) Metadata cache for the specified objects, or false on failure.


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Source Source

File: wp-includes/meta.php

function update_meta_cache( $meta_type, $object_ids ) {
	global $wpdb;

	if ( ! $meta_type || ! $object_ids ) {
		return false;
	}

	$table = _get_meta_table( $meta_type );
	if ( ! $table ) {
		return false;
	}

	$column = sanitize_key( $meta_type . '_id' );

	if ( ! is_array( $object_ids ) ) {
		$object_ids = preg_replace( '|[^0-9,]|', '', $object_ids );
		$object_ids = explode( ',', $object_ids );
	}

	$object_ids = array_map( 'intval', $object_ids );

	/**
	 * Filters whether to update the metadata cache of a specific type.
	 *
	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
	 * object type (comment, post, term, or user). Returning a non-null value
	 * will effectively short-circuit the function.
	 *
	 * @since 5.0.0
	 *
	 * @param mixed $check      Whether to allow updating the meta cache of the given type.
	 * @param int[] $object_ids Array of object IDs to update the meta cache for.
	 */
	$check = apply_filters( "update_{$meta_type}_metadata_cache", null, $object_ids );
	if ( null !== $check ) {
		return (bool) $check;
	}

	$cache_key = $meta_type . '_meta';
	$ids       = array();
	$cache     = array();
	foreach ( $object_ids as $id ) {
		$cached_object = wp_cache_get( $id, $cache_key );
		if ( false === $cached_object ) {
			$ids[] = $id;
		} else {
			$cache[ $id ] = $cached_object;
		}
	}

	if ( empty( $ids ) ) {
		return $cache;
	}

	// Get meta info
	$id_list   = join( ',', $ids );
	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
	$meta_list = $wpdb->get_results( "SELECT $column, meta_key, meta_value FROM $table WHERE $column IN ($id_list) ORDER BY $id_column ASC", ARRAY_A );

	if ( ! empty( $meta_list ) ) {
		foreach ( $meta_list as $metarow ) {
			$mpid = intval( $metarow[ $column ] );
			$mkey = $metarow['meta_key'];
			$mval = $metarow['meta_value'];

			// Force subkeys to be array type:
			if ( ! isset( $cache[ $mpid ] ) || ! is_array( $cache[ $mpid ] ) ) {
				$cache[ $mpid ] = array();
			}
			if ( ! isset( $cache[ $mpid ][ $mkey ] ) || ! is_array( $cache[ $mpid ][ $mkey ] ) ) {
				$cache[ $mpid ][ $mkey ] = array();
			}

			// Add a value to the current pid/key:
			$cache[ $mpid ][ $mkey ][] = $mval;
		}
	}

	foreach ( $ids as $id ) {
		if ( ! isset( $cache[ $id ] ) ) {
			$cache[ $id ] = array();
		}
		wp_cache_add( $id, $cache[ $id ], $cache_key );
	}

	return $cache;
}

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Changelog Changelog

Changelog
Version Description
2.9.0 Introduced.


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