get_bookmarks( string|array $args = '' )

检索书签列表
Retrieves the list of bookmarks

说明（Description）

尝试首先基于参数的MD5哈希从缓存中检索。如果失败，那么将根据参数构建查询并执行。结果将存储到缓存中。

返回（Return）

源码（Source）

/**
 * Retrieves the list of bookmarks
 *
 * Attempts to retrieve from the cache first based on MD5 hash of arguments. If
 * that fails, then the query will be built from the arguments and executed. The
 * results will be stored to the cache.
 *
 * @since 2.1.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string|array $args {
 *     Optional. String or array of arguments to retrieve bookmarks.
 *
 *     @type string   $orderby        How to order the links by. Accepts post fields. Default 'name'.
 *     @type string   $order          Whether to order bookmarks in ascending or descending order.
 *                                    Accepts 'ASC' (ascending) or 'DESC' (descending). Default 'ASC'.
 *     @type int      $limit          Amount of bookmarks to display. Accepts 1+ or -1 for all.
 *                                    Default -1.
 *     @type string   $category       Comma-separated list of category ids to include links from.
 *                                    Default empty.
 *     @type string   $category_name  Category to retrieve links for by name. Default empty.
 *     @type int|bool $hide_invisible Whether to show or hide links marked as 'invisible'. Accepts
 *                                    1|true or 0|false. Default 1|true.
 *     @type int|bool $show_updated   Whether to display the time the bookmark was last updated.
 *                                    Accepts 1|true or 0|false. Default 0|false.
 *     @type string   $include        Comma-separated list of bookmark IDs to include. Default empty.
 *     @type string   $exclude        Comma-separated list of bookmark IDs to exclude. Default empty.
 * }
 * @return array List of bookmark row objects.
 */
function get_bookmarks( $args = '' ) {
	global $wpdb;

	$defaults = array(
		'orderby' => 'name', 'order' => 'ASC',
		'limit' => -1, 'category' => '',
		'category_name' => '', 'hide_invisible' => 1,
		'show_updated' => 0, 'include' => '',
		'exclude' => '', 'search' => ''
	);

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

	$key = md5( serialize( $r ) );
	if ( $cache = wp_cache_get( 'get_bookmarks', 'bookmark' ) ) {
		if ( is_array( $cache ) && isset( $cache[ $key ] ) ) {
			$bookmarks = $cache[ $key ];
			/**
			 * Filter the returned list of bookmarks.
			 *
			 * The first time the hook is evaluated in this file, it returns the cached
			 * bookmarks list. The second evaluation returns a cached bookmarks list if the
			 * link category is passed but does not exist. The third evaluation returns
			 * the full cached results.
			 *
			 * @since 2.1.0
			 *
			 * @see get_bookmarks()
			 *
			 * @param array $bookmarks List of the cached bookmarks.
			 * @param array $r         An array of bookmark query arguments.
			 */
			return apply_filters( 'get_bookmarks', $bookmarks, $r );
		}
	}

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

	$inclusions = '';
	if ( ! empty( $r['include'] ) ) {
		$r['exclude'] = '';  //ignore exclude, category, and category_name params if using include
		$r['category'] = '';
		$r['category_name'] = '';
		$inclinks = preg_split( '/[s,]+/', $r['include'] );
		if ( count( $inclinks ) ) {
			foreach ( $inclinks as $inclink ) {
				if ( empty( $inclusions ) ) {
					$inclusions = ' AND ( link_id = ' . intval( $inclink ) . ' ';
				} else {
					$inclusions .= ' OR link_id = ' . intval( $inclink ) . ' ';
				}
			}
		}
	}
	if (! empty( $inclusions ) ) {
		$inclusions .= ')';
	}

	$exclusions = '';
	if ( ! empty( $r['exclude'] ) ) {
		$exlinks = preg_split( '/[s,]+/', $r['exclude'] );
		if ( count( $exlinks ) ) {
			foreach ( $exlinks as $exlink ) {
				if ( empty( $exclusions ) ) {
					$exclusions = ' AND ( link_id <> ' . intval( $exlink ) . ' ';
				} else {
					$exclusions .= ' AND link_id <> ' . intval( $exlink ) . ' ';
				}
			}
		}
	}
	if ( ! empty( $exclusions ) ) {
		$exclusions .= ')';
	}

	if ( ! empty( $r['category_name'] ) ) {
		if ( $r['category'] = get_term_by('name', $r['category_name'], 'link_category') ) {
			$r['category'] = $r['category']->term_id;
		} else {
			$cache[ $key ] = array();
			wp_cache_set( 'get_bookmarks', $cache, 'bookmark' );
			/** This filter is documented in wp-includes/bookmark.php */
			return apply_filters( 'get_bookmarks', array(), $r );
		}
	}

	$search = '';
	if ( ! empty( $r['search'] ) ) {
		$like = '%' . $wpdb->esc_like( $r['search'] ) . '%';
		$search = $wpdb->prepare(" AND ( (link_url LIKE %s) OR (link_name LIKE %s) OR (link_description LIKE %s) ) ", $like, $like, $like );
	}

	$category_query = '';
	$join = '';
	if ( ! empty( $r['category'] ) ) {
		$incategories = preg_split( '/[s,]+/', $r['category'] );
		if ( count($incategories) ) {
			foreach ( $incategories as $incat ) {
				if ( empty( $category_query ) ) {
					$category_query = ' AND ( tt.term_id = ' . intval( $incat ) . ' ';
				} else {
					$category_query .= ' OR tt.term_id = ' . intval( $incat ) . ' ';
				}
			}
		}
	}
	if ( ! empty( $category_query ) ) {
		$category_query .= ") AND taxonomy = 'link_category'";
		$join = " INNER JOIN $wpdb->term_relationships AS tr ON ($wpdb->links.link_id = tr.object_id) INNER JOIN $wpdb->term_taxonomy as tt ON tt.term_taxonomy_id = tr.term_taxonomy_id";
	}

	if ( $r['show_updated'] ) {
		$recently_updated_test = ", IF (DATE_ADD(link_updated, INTERVAL 120 MINUTE) >= NOW(), 1,0) as recently_updated ";
	} else {
		$recently_updated_test = '';
	}

	$get_updated = ( $r['show_updated'] ) ? ', UNIX_TIMESTAMP(link_updated) AS link_updated_f ' : '';

	$orderby = strtolower( $r['orderby'] );
	$length = '';
	switch ( $orderby ) {
		case 'length':
			$length = ", CHAR_LENGTH(link_name) AS length";
			break;
		case 'rand':
			$orderby = 'rand()';
			break;
		case 'link_id':
			$orderby = "$wpdb->links.link_id";
			break;
		default:
			$orderparams = array();
			$keys = array( 'link_id', 'link_name', 'link_url', 'link_visible', 'link_rating', 'link_owner', 'link_updated', 'link_notes', 'link_description' );
			foreach ( explode( ',', $orderby ) as $ordparam ) {
				$ordparam = trim( $ordparam );

				if ( in_array( 'link_' . $ordparam, $keys ) ) {
					$orderparams[] = 'link_' . $ordparam;
				} elseif ( in_array( $ordparam, $keys ) ) {
					$orderparams[] = $ordparam;
				}
			}
			$orderby = implode( ',', $orderparams );
	}

	if ( empty( $orderby ) ) {
		$orderby = 'link_name';
	}

	$order = strtoupper( $r['order'] );
	if ( '' !== $order && ! in_array( $order, array( 'ASC', 'DESC' ) ) ) {
		$order = 'ASC';
	}

	$visible = '';
	if ( $r['hide_invisible'] ) {
		$visible = "AND link_visible = 'Y'";
	}

	$query = "SELECT * $length $recently_updated_test $get_updated FROM $wpdb->links $join WHERE 1=1 $visible $category_query";
	$query .= " $exclusions $inclusions $search";
	$query .= " ORDER BY $orderby $order";
	if ( $r['limit'] != -1 ) {
		$query .= ' LIMIT ' . $r['limit'];
	}

	$results = $wpdb->get_results( $query );

	$cache[ $key ] = $results;
	wp_cache_set( 'get_bookmarks', $cache, 'bookmark' );

	/** This filter is documented in wp-includes/bookmark.php */
	return apply_filters( 'get_bookmarks', $results, $r );
}

笔记（Notes）