wp_get_object_terms( int|int[] $object_ids, string|string[] $taxonomies, array|string $args = array() ): WP_Term[]|int[]|string[]|string|WP_Error

Retrieves the terms associated with the given object(s), in the supplied taxonomies.

Parameters

$object_idsint|int[]required
The ID(s) of the object(s) to retrieve.
$taxonomiesstring|string[]required
The taxonomy names to retrieve terms from.
$argsarray|stringoptional
See WP_Term_Query::__construct() for supported arguments.

Default:array()

Return

WP_Term[]|int[]|string[]|string|WP_Error Array of terms, a count thereof as a numeric string, or WP_Error if any of the taxonomies do not exist.
See WP_Term_Query::get_terms() for more information.

More Information

It should be noted that the results from wp_get_object_terms are not cached which will result in a db call everytime this function is called. For performance, functions like get_the_terms() (which the results of has been cached), should be used.

Source

function wp_get_object_terms( $object_ids, $taxonomies, $args = array() ) {
	if ( empty( $object_ids ) || empty( $taxonomies ) ) {
		return array();
	}

	if ( ! is_array( $taxonomies ) ) {
		$taxonomies = array( $taxonomies );
	}

	foreach ( $taxonomies as $taxonomy ) {
		if ( ! taxonomy_exists( $taxonomy ) ) {
			return new WP_Error( 'invalid_taxonomy', __( 'Invalid taxonomy.' ) );
		}
	}

	if ( ! is_array( $object_ids ) ) {
		$object_ids = array( $object_ids );
	}
	$object_ids = array_map( 'intval', $object_ids );

	$defaults = array(
		'update_term_meta_cache' => false,
	);

	$args = wp_parse_args( $args, $defaults );

	/**
	 * Filters arguments for retrieving object terms.
	 *
	 * @since 4.9.0
	 *
	 * @param array    $args       An array of arguments for retrieving terms for the given object(s).
	 *                             See wp_get_object_terms() for details.
	 * @param int[]    $object_ids Array of object IDs.
	 * @param string[] $taxonomies Array of taxonomy names to retrieve terms from.
	 */
	$args = apply_filters( 'wp_get_object_terms_args', $args, $object_ids, $taxonomies );

	/*
	 * When one or more queried taxonomies is registered with an 'args' array,
	 * those params override the `$args` passed to this function.
	 */
	$terms = array();
	if ( count( $taxonomies ) > 1 ) {
		foreach ( $taxonomies as $index => $taxonomy ) {
			$t = get_taxonomy( $taxonomy );
			if ( isset( $t->args ) && is_array( $t->args ) && array_merge( $args, $t->args ) != $args ) {
				unset( $taxonomies[ $index ] );
				$terms = array_merge( $terms, wp_get_object_terms( $object_ids, $taxonomy, array_merge( $args, $t->args ) ) );
			}
		}
	} else {
		$t = get_taxonomy( $taxonomies[0] );
		if ( isset( $t->args ) && is_array( $t->args ) ) {
			$args = array_merge( $args, $t->args );
		}
	}

	$args['taxonomy']   = $taxonomies;
	$args['object_ids'] = $object_ids;

	// Taxonomies registered without an 'args' param are handled here.
	if ( ! empty( $taxonomies ) ) {
		$terms_from_remaining_taxonomies = get_terms( $args );

		// Array keys should be preserved for values of $fields that use term_id for keys.
		if ( ! empty( $args['fields'] ) && str_starts_with( $args['fields'], 'id=>' ) ) {
			$terms = $terms + $terms_from_remaining_taxonomies;
		} else {
			$terms = array_merge( $terms, $terms_from_remaining_taxonomies );
		}
	}

	/**
	 * Filters the terms for a given object or objects.
	 *
	 * @since 4.2.0
	 *
	 * @param WP_Term[]|int[]|string[]|string $terms      Array of terms or a count thereof as a numeric string.
	 * @param int[]                           $object_ids Array of object IDs for which terms were retrieved.
	 * @param string[]                        $taxonomies Array of taxonomy names from which terms were retrieved.
	 * @param array                           $args       Array of arguments for retrieving terms for the given
	 *                                                    object(s). See wp_get_object_terms() for details.
	 */
	$terms = apply_filters( 'get_object_terms', $terms, $object_ids, $taxonomies, $args );

	$object_ids = implode( ',', $object_ids );
	$taxonomies = "'" . implode( "', '", array_map( 'esc_sql', $taxonomies ) ) . "'";

	/**
	 * Filters the terms for a given object or objects.
	 *
	 * The `$taxonomies` parameter passed to this filter is formatted as a SQL fragment. The
	 * 'get_object_terms' filter is recommended as an alternative.
	 *
	 * @since 2.8.0
	 *
	 * @param WP_Term[]|int[]|string[]|string $terms      Array of terms or a count thereof as a numeric string.
	 * @param string                          $object_ids Comma separated list of object IDs for which terms were retrieved.
	 * @param string                          $taxonomies SQL fragment of taxonomy names from which terms were retrieved.
	 * @param array                           $args       Array of arguments for retrieving terms for the given
	 *                                                    object(s). See wp_get_object_terms() for details.
	 */
	return apply_filters( 'wp_get_object_terms', $terms, $object_ids, $taxonomies, $args );
}

Hooks

apply_filters( ‘get_object_terms’, WP_Term[]|int[]|string[]|string $terms, int[] $object_ids, string[] $taxonomies, array $args )

Filters the terms for a given object or objects.

apply_filters( ‘wp_get_object_terms’, WP_Term[]|int[]|string[]|string $terms, string $object_ids, string $taxonomies, array $args )

Filters the terms for a given object or objects.

apply_filters( ‘wp_get_object_terms_args’, array $args, int[] $object_ids, string[] $taxonomies )

Filters arguments for retrieving object terms.

Changelog

VersionDescription
6.3.0Passing update_term_meta_cache argument value false by default resulting in get_terms() to not prime the term meta cache.
4.7.0Refactored to use WP_Term_Query, and to support any WP_Term_Query arguments.
4.4.0Introduced $meta_query and $update_term_meta_cache arguments. When $fields is 'all' or 'all_with_object_id', an array of WP_Term objects will be returned.
4.2.0Added support for 'taxonomy', 'parent', and 'term_taxonomy_id' values of $orderby.
Introduced $parent argument.
2.3.0Introduced.

User Contributed Notes

  1. Skip to note 4 content

    It’s very important to note that if you wish to get the taxonomy terms for a given post, your first choice should be using get_the_terms() since it uses the WordPress object cache and can potentialy save a lot of extra queries.

    This is specially useful if you’re looping over posts results, because WP_Query by default loads all the terms for the queried posts.

  2. Skip to note 5 content

    Example

    Returns a list of all ‘product’ taxonomy terms that are applied to $post:

    $product_terms = wp_get_object_terms( $post->ID,  'product' );
    
    if ( ! empty( $product_terms ) ) {
    	if ( ! is_wp_error( $product_terms ) ) {
    		echo '<ul>';
    			foreach( $product_terms as $term ) {
    				echo '<li><a href="' . esc_url( get_term_link( $term->slug, 'product' ) ) . '">' . esc_html( $term->name ) . '</a></li>'; 
    			}
    		echo '</ul>';
    	}
    }
  3. Skip to note 6 content

    Example of related EDD products

      $exclude_post_id = $post->ID;
                      $taxchoice =  'download_tag';
                      $custom_taxterms = wp_get_object_terms( $post->ID, $taxchoice, array('fields' => 'ids') );
                      $arguments = array(
                        'post_type' => 'download',
                        'post_status' => 'publish',
                        'posts_per_page' => 3,
                        'orderby' => 'rand',
                        'ignore_sticky_posts' => 1,
                        'post__not_in' => array($post->ID, '81099'),
                        'ignore_sticky_posts'=>1,
                        'tax_query' => array(
                                array(
                                  'taxonomy' => $taxchoice,
                                  'field' => 'id',
                                  'terms' => $custom_taxterms
                                )
                              ),
                      );
    
                      $post_query = new WP_Query($arguments);

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