wp_unique_post_slug

Source code

function wp_unique_post_slug( $slug, $post_ID, $post_status, $post_type, $post_parent ) {

	if ( in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) )

		return $slug;



	global $wpdb, $wp_rewrite;



	$feeds = $wp_rewrite->feeds;

	if ( ! is_array( $feeds ) )

		$feeds = array();



	$hierarchical_post_types = get_post_types( array('hierarchical' => true) );

	if ( 'attachment' == $post_type ) {

		// Attachment slugs must be unique across all types.

		$check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND ID != %d LIMIT 1";

		$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_ID ) );



		if ( $post_name_check || in_array( $slug, $feeds ) || apply_filters( 'wp_unique_post_slug_is_bad_attachment_slug', false, $slug ) ) {

			$suffix = 2;

			do {

				$alt_post_name = substr ($slug, 0, 200 - ( strlen( $suffix ) + 1 ) ) . "-$suffix";

				$post_name_check = $wpdb->get_var( $wpdb->prepare($check_sql, $alt_post_name, $post_ID ) );

				$suffix++;

			} while ( $post_name_check );

			$slug = $alt_post_name;

		}

	} elseif ( in_array( $post_type, $hierarchical_post_types ) ) {

		// Page slugs must be unique within their own trees. Pages are in a separate

		// namespace than posts so page slugs are allowed to overlap post slugs.

		$check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type IN ( '" . implode( "', '", esc_sql( $hierarchical_post_types ) ) . "' ) AND ID != %d AND post_parent = %d LIMIT 1";

		$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_ID, $post_parent ) );



		if ( $post_name_check || in_array( $slug, $feeds ) || preg_match( "@^($wp_rewrite->pagination_base)?\d+$@", $slug )  || apply_filters( 'wp_unique_post_slug_is_bad_hierarchical_slug', false, $slug, $post_type, $post_parent ) ) {

			$suffix = 2;

			do {

				$alt_post_name = substr( $slug, 0, 200 - ( strlen( $suffix ) + 1 ) ) . "-$suffix";

				$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $alt_post_name, $post_ID, $post_parent ) );

				$suffix++;

			} while ( $post_name_check );

			$slug = $alt_post_name;

		}

	} else {

		// Post slugs must be unique across all posts.

		$check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type = %s AND ID != %d LIMIT 1";

		$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_type, $post_ID ) );



		if ( $post_name_check || in_array( $slug, $feeds ) || apply_filters( 'wp_unique_post_slug_is_bad_flat_slug', false, $slug, $post_type ) ) {

			$suffix = 2;

			do {

				$alt_post_name = substr( $slug, 0, 200 - ( strlen( $suffix ) + 1 ) ) . "-$suffix";

				$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $alt_post_name, $post_type, $post_ID ) );

				$suffix++;

			} while ( $post_name_check );

			$slug = $alt_post_name;

		}

	}



	return apply_filters( 'wp_unique_post_slug', $slug, $post_ID, $post_status, $post_type, $post_parent );

}