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get_metadata_raw() WP 5.5.0

Retrieves raw metadata value for the specified object.

Hooks from the function
Return

Mixed. Single metadata value, or array of values. Null if the value does not exist. False if there's a problem with the parameters passed to the function.

Usage

get_metadata_raw( $meta_type, $object_id, $meta_key, $single );
$meta_type(string) (required)
Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user', or any other object type with an associated meta table.
$object_id(int) (required)
ID of the object metadata is for.
$meta_key(string)
Metadata key. If not specified, retrieve all metadata for the specified object.
Default: ''
$single(true|false)
If true, return only the first value of the specified meta_key. This parameter has no effect if meta_key is not specified.
Default: false

Changelog

Since 5.5.0 Introduced.

Code of get_metadata_raw() WP 5.7.2

<?php
function get_metadata_raw( $meta_type, $object_id, $meta_key = '', $single = false ) {
	if ( ! $meta_type || ! is_numeric( $object_id ) ) {
		return false;
	}

	$object_id = absint( $object_id );
	if ( ! $object_id ) {
		return false;
	}

	/**
	 * Short-circuits the return value of a meta field.
	 *
	 * The dynamic portion of the hook, `$meta_type`, refers to the meta object type
	 * (post, comment, term, user, or any other type with an associated meta table).
	 * Returning a non-null value will effectively short-circuit the function.
	 *
	 * Possible filter names include:
	 *
	 *  - `get_post_metadata`
	 *  - `get_comment_metadata`
	 *  - `get_term_metadata`
	 *  - `get_user_metadata`
	 *
	 * @since 3.1.0
	 * @since 5.5.0 Added the `$meta_type` parameter.
	 *
	 * @param mixed  $value     The value to return, either a single metadata value or an array
	 *                          of values depending on the value of `$single`. Default null.
	 * @param int    $object_id ID of the object metadata is for.
	 * @param string $meta_key  Metadata key.
	 * @param bool   $single    Whether to return only the first value of the specified `$meta_key`.
	 * @param string $meta_type Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user',
	 *                          or any other object type with an associated meta table.
	 */
	$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, $single, $meta_type );
	if ( null !== $check ) {
		if ( $single && is_array( $check ) ) {
			return $check[0];
		} else {
			return $check;
		}
	}

	$meta_cache = wp_cache_get( $object_id, $meta_type . '_meta' );

	if ( ! $meta_cache ) {
		$meta_cache = update_meta_cache( $meta_type, array( $object_id ) );
		if ( isset( $meta_cache[ $object_id ] ) ) {
			$meta_cache = $meta_cache[ $object_id ];
		} else {
			$meta_cache = null;
		}
	}

	if ( ! $meta_key ) {
		return $meta_cache;
	}

	if ( isset( $meta_cache[ $meta_key ] ) ) {
		if ( $single ) {
			return maybe_unserialize( $meta_cache[ $meta_key ][0] );
		} else {
			return array_map( 'maybe_unserialize', $meta_cache[ $meta_key ] );
		}
	}

	return null;
}