<?php
/**
* Core Metadata API
*
* 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
*/
/**
* Add metadata for the specified object.
*
* @since 2.9.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @param string $meta_type Type of object metadata is for (e.g., comment, post, term, or user).
* @param int $object_id ID of the object metadata is for
* @param string $meta_key Metadata key
* @param mixed $meta_value Metadata value. Must be serializable if non-scalar.
* @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 int|false The meta ID on success, false on failure.
*/
function add_metadata( $meta_type, $object_id, $meta_key, $meta_value, $unique = false ) {
global $wpdb;
if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) ) {
return false;
}
$object_id = absint( $object_id );
if ( ! $object_id ) {
return false;
}
$table = _get_meta_table( $meta_type );
if ( ! $table ) {
return false;
}
$meta_subtype = get_object_subtype( $meta_type, $object_id );
$column = sanitize_key( $meta_type . '_id' );
// expected_slashed ($meta_key)
$meta_key = wp_unslash( $meta_key );
$meta_value = wp_unslash( $meta_value );
$meta_value = sanitize_meta( $meta_key, $meta_value, $meta_type, $meta_subtype );
/**
* Filters whether to add metadata of a specific type.
*
* The dynamic portion of the hook, `$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 3.1.0
*
* @param null|bool $check Whether to allow adding metadata for the given type.
* @param int $object_id Object ID.
* @param string $meta_key Meta key.
* @param mixed $meta_value Meta value. Must be serializable if non-scalar.
* @param bool $unique Whether the specified meta key should be unique
* for the object. Optional. Default false.
*/
$check = apply_filters( "add_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $unique );
if ( null !== $check ) {
return $check;
}
if ( $unique && $wpdb->get_var(
$wpdb->prepare(
"SELECT COUNT(*) FROM $table WHERE meta_key = %s AND $column = %d",
$meta_key,
$object_id
)
) ) {
return false;
}
$_meta_value = $meta_value;
$meta_value = maybe_serialize( $meta_value );
/**
* Fires immediately before meta of a specific type is added.
*
* The dynamic portion of the hook, `$meta_type`, refers to the meta
* object type (comment, post, term, or user).
*
* @since 3.1.0
*
* @param int $object_id Object ID.
* @param string $meta_key Meta key.
* @param mixed $_meta_value Meta value.
*/
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