<?php
/**
- * Meta API
+ * Metadata API
*
- * Functions for retrieving and manipulating metadata
+ * Functions for retrieving and manipulating metadata of various WordPress object types. Metadata
+ * for an object is a represented by a simple key-value pair. Objects may contain multiple
+ * metadata entries that share the same key and differ only in their value.
*
* @package WordPress
* @subpackage Meta
* @since 2.9.0
*/
+/**
+ * Add metadata for the specified object.
+ *
+ * @since 2.9.0
+ * @uses $wpdb WordPress database object for queries.
+ * @uses do_action() Calls 'added_{$meta_type}_meta' with meta_id of added metadata entry,
+ * object ID, meta key, and meta value
+ *
+ * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
+ * @param int $object_id ID of the object metadata is for
+ * @param string $meta_key Metadata key
+ * @param string $meta_value Metadata value
+ * @param bool $unique Optional, default is false. Whether the specified metadata key should be
+ * unique for the object. If true, and the object already has a value for the specified
+ * metadata key, no change will be made
+ * @return bool True on successful update, false on failure.
+ */
function add_metadata($meta_type, $object_id, $meta_key, $meta_value, $unique = false) {
if ( !$meta_type || !$meta_key )
return false;
+ if ( !$object_id = absint($object_id) )
+ return false;
+
if ( ! $table = _get_meta_table($meta_type) )
return false;
$meta_key, $object_id ) ) )
return false;
+ $_meta_value = $meta_value;
$meta_value = maybe_serialize( stripslashes_deep($meta_value) );
$wpdb->insert( $table, array(
) );
wp_cache_delete($object_id, $meta_type . '_meta');
+ // users cache stores usermeta that must be cleared.
+ if ( 'user' == $meta_type )
+ clean_user_cache($object_id);
- do_action( "added_{$meta_type}_meta", $wpdb->insert_id, $object_id, $meta_key, $meta_value );
+ do_action( "added_{$meta_type}_meta", $wpdb->insert_id, $object_id, $meta_key, $_meta_value );
return true;
}
+/**
+ * Update metadata for the specified object. If no value already exists for the specified object
+ * ID and metadata key, the metadata will be added.
+ *
+ * @since 2.9.0
+ * @uses $wpdb WordPress database object for queries.
+ * @uses do_action() Calls 'update_{$meta_type}_meta' before updating metadata with meta_id of
+ * metadata entry to update, object ID, meta key, and meta value
+ * @uses do_action() Calls 'updated_{$meta_type}_meta' after updating metadata with meta_id of
+ * updated metadata entry, object ID, meta key, and meta value
+ *
+ * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
+ * @param int $object_id ID of the object metadata is for
+ * @param string $meta_key Metadata key
+ * @param string $meta_value Metadata value
+ * @param string $prev_value Optional. If specified, only update existing metadata entries with
+ * the specified value. Otherwise, update all entries.
+ * @return bool True on successful update, false on failure.
+ */
function update_metadata($meta_type, $object_id, $meta_key, $meta_value, $prev_value = '') {
if ( !$meta_type || !$meta_key )
return false;
+ if ( !$object_id = absint($object_id) )
+ return false;
+
if ( ! $table = _get_meta_table($meta_type) )
return false;
if ( ! $meta_id = $wpdb->get_var( $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s AND $column = %d", $meta_key, $object_id ) ) )
return add_metadata($meta_type, $object_id, $meta_key, $meta_value);
+ // Compare existing value to new value if no prev value given and the key exists only once.
+ if ( empty($prev_value) ) {
+ $old_value = get_metadata($meta_type, $object_id, $meta_key);
+ if ( count($old_value) == 1 ) {
+ if ( $old_value[0] === $meta_value )
+ return false;
+ }
+ }
+
+ $_meta_value = $meta_value;
$meta_value = maybe_serialize( stripslashes_deep($meta_value) );
$data = compact( 'meta_value' );
$where['meta_value'] = $prev_value;
}
- do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $meta_value );
+ do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
$wpdb->update( $table, $data, $where );
wp_cache_delete($object_id, $meta_type . '_meta');
+ // users cache stores usermeta that must be cleared.
+ if ( 'user' == $meta_type )
+ clean_user_cache($object_id);
- do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $meta_value );
+ do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
return true;
}
+/**
+ * Delete metadata for the specified object.
+ *
+ * @since 2.9.0
+ * @uses $wpdb WordPress database object for queries.
+ * @uses do_action() Calls 'deleted_{$meta_type}_meta' after deleting with meta_id of
+ * deleted metadata entries, object ID, meta key, and meta value
+ *
+ * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
+ * @param int $object_id ID of the object metadata is for
+ * @param string $meta_key Metadata key
+ * @param string $meta_value Optional. Metadata value. If specified, only delete metadata entries
+ * with this value. Otherwise, delete all entries with the specified meta_key.
+ * @param bool $delete_all Optional, default is false. If true, delete matching metadata entries
+ * for all objects, ignoring the specified object_id. Otherwise, only delete matching
+ * metadata entries for the specified object_id.
+ * @return bool True on successful delete, false on failure.
+ */
function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false) {
- if ( !$meta_type || !$meta_key || (!$delete_all && ! (int)$object_id) )
+ if ( !$meta_type || !$meta_key )
+ return false;
+
+ if ( (!$object_id = absint($object_id)) && !$delete_all )
return false;
if ( ! $table = _get_meta_table($meta_type) )
return false;
wp_cache_delete($object_id, $meta_type . '_meta');
+ // users cache stores usermeta that must be cleared.
+ if ( 'user' == $meta_type )
+ clean_user_cache($object_id);
do_action( "deleted_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $meta_value );
return true;
}
+/**
+ * Retrieve metadata for the specified object.
+ *
+ * @since 2.9.0
+ *
+ * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
+ * @param int $object_id ID of the object metadata is for
+ * @param string $meta_key Optional. Metadata key. If not specified, retrieve all metadata for
+ * the specified object.
+ * @param bool $single Optional, default is false. If true, return only the first value of the
+ * specified meta_key. This parameter has no effect if meta_key is not specified.
+ * @return string|array Single metadata value, or array of values
+ */
function get_metadata($meta_type, $object_id, $meta_key = '', $single = false) {
if ( !$meta_type )
return false;
+ if ( !$object_id = absint($object_id) )
+ return false;
+
$meta_cache = wp_cache_get($object_id, $meta_type . '_meta');
if ( !$meta_cache ) {
return $meta_cache;
if ( isset($meta_cache[$meta_key]) ) {
- if ( $single ) {
+ if ( $single )
return maybe_unserialize( $meta_cache[$meta_key][0] );
- } else {
+ else
return array_map('maybe_unserialize', $meta_cache[$meta_key]);
- }
}
if ($single)
return array();
}
+/**
+ * Update the metadata cache for the specified objects.
+ *
+ * @since 2.9.0
+ * @uses $wpdb WordPress database object for queries.
+ *
+ * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
+ * @param int|array $object_ids array or comma delimited list of object IDs to update cache for
+ * @return mixed Metadata cache for the specified objects, or false on failure.
+ */
function update_meta_cache($meta_type, $object_ids) {
if ( empty( $meta_type ) || empty( $object_ids ) )
return false;
return $cache;
}
+/**
+ * Retrieve the name of the metadata table for the specified object type.
+ *
+ * @since 2.9.0
+ * @uses $wpdb WordPress database object for queries.
+ *
+ * @param string $meta_type Type of object to get metadata table for (e.g., comment, post, or user)
+ * @return mixed Metadata table name, or false if no metadata table exists
+ */
function _get_meta_table($type) {
global $wpdb;
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