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wp_unique_term_slug › WordPress Function

Since2.3.0
Deprecatedn/a
› wp_unique_term_slug ( $slug, $term )
Parameters: (2)
  • (string) $slug The string that will be tried for a unique slug.
    Required: Yes
  • (object) $term The term object that the `$slug` will belong to.
    Required: Yes
Returns:
  • (string) Will return a true unique slug.
Defined at:
Codex:
Change Log:
  • 7.2.0

Makes term slug unique, if it isn't already.

The $slug has to be unique global to every taxonomy, meaning that one taxonomy term can't have a matching slug with another taxonomy term. Each slug has to be globally unique for every taxonomy. The way this works is that if the taxonomy that the term belongs to is hierarchical and has a parent, it will append that parent to the $slug. If that still doesn't return a unique slug, then it tries to append a number until it finds a number that is truly unique. Appending a parent slug or a number can push the result past the 200 character limit of the slug column in the terms table, so the slug is truncated to make room for whatever is appended to it. The only purpose for $term is for appending a parent, if one exists.


Related Functions: wp_unique_post_slug, wp_unique_id_from_values, wp_truncate_slug, wp_count_terms, wp_unique_id

Source 

function wp_unique_term_slug( $slug, $term ) {
	global $wpdb;

	$needs_suffix  = true;
	$original_slug = $slug;

	// As of 4.1, duplicate slugs are allowed as long as they're in different taxonomies.
	if ( ! term_exists( $slug ) || get_option( 'db_version' ) >= 30133 && ! get_term_by( 'slug', $slug, $term->taxonomy ) ) {
		$needs_suffix = false;
	}

	/*
	 * If the taxonomy supports hierarchy and the term has a parent, make the slug unique
	 * by incorporating parent slugs.
	 */
	$parent_suffix = '';
	if ( $needs_suffix && is_taxonomy_hierarchical( $term->taxonomy ) && ! empty( $term->parent ) ) {
		$the_parent = $term->parent;
		while ( ! empty( $the_parent ) ) {
			$parent_term = get_term( $the_parent, $term->taxonomy );
			if ( is_wp_error( $parent_term ) || empty( $parent_term ) ) {
				break;
			}
			$parent_suffix .= '-' . $parent_term->slug;
			if ( ! term_exists( $slug . $parent_suffix ) ) {
				break;
			}

			if ( empty( $parent_term->parent ) ) {
				break;
			}
			$the_parent = $parent_term->parent;
		}
	}

	// If we didn't get a unique slug, try appending a number to make it unique.

	/**
	 * Filters whether the proposed unique term slug is bad.
	 *
	 * @since 4.3.0
	 *
	 * @param bool   $needs_suffix Whether the slug needs to be made unique with a suffix.
	 * @param string $slug         The slug.
	 * @param object $term         Term object.
	 */
	if ( apply_filters( 'wp_unique_term_slug_is_bad_slug', $needs_suffix, $slug, $term ) ) {
		if ( $parent_suffix ) {
			$slug = wp_truncate_slug( $slug . $parent_suffix, 200 );
		}

		if ( ! empty( $term->term_id ) ) {
			$query = $wpdb->prepare( "SELECT slug FROM $wpdb->terms WHERE slug = %s AND term_id != %d", $slug, $term->term_id );
		} else {
			$query = $wpdb->prepare( "SELECT slug FROM $wpdb->terms WHERE slug = %s", $slug );
		}

		if ( $wpdb->get_var( $query ) ) { // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
			$num = 2;
			do {
				// Reserve room for the suffix so the result still fits the 200 character column.
				$numeric_suffix = "-$num";
				$alt_slug       = wp_truncate_slug( $slug, 200 - strlen( $numeric_suffix ) ) . $numeric_suffix;
				++$num;
				$slug_check = $wpdb->get_var( $wpdb->prepare( "SELECT slug FROM $wpdb->terms WHERE slug = %s", $alt_slug ) );
			} while ( $slug_check );
			$slug = $alt_slug;
		}
	}

	/**
	 * Filters the unique term slug.
	 *
	 * @since 4.3.0
	 *
	 * @param string $slug          Unique term slug.
	 * @param object $term          Term object.
	 * @param string $original_slug Slug originally passed to the function for testing.
	 */
	return apply_filters( 'wp_unique_term_slug', $slug, $term, $original_slug );
}