get_bookmarks

get_bookmarks: 這個函式從WordPress資料庫中檢索一個書籤（連結）的列表: 該函式接受一個引數陣列，指定要檢索的書籤（例如，類別、標籤、搜尋詞），並返回一個書籤物件陣列。

檢索書籤列表。

根據引數的MD5雜湊值，首先嚐試從快取中檢索。如果失敗了，那麼將根據引數建立查詢並執行。結果將被儲存到快取中。

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'         => '',
	);

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

	$key   = md5( serialize( $parsed_args ) );
	$cache = wp_cache_get( 'get_bookmarks', 'bookmark' );

	if ( 'rand' !== $parsed_args['orderby'] && $cache ) {
		if ( is_array( $cache ) && isset( $cache[ $key ] ) ) {
			$bookmarks = $cache[ $key ];
			/**
			 * Filters 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 $parsed_args An array of bookmark query arguments.
			 */
			return apply_filters( 'get_bookmarks', $bookmarks, $parsed_args );
		}
	}

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

	$inclusions = '';
	if ( ! empty( $parsed_args['include'] ) ) {
		$parsed_args['exclude']       = '';  // Ignore exclude, category, and category_name params if using include.
		$parsed_args['category']      = '';
		$parsed_args['category_name'] = '';

		$inclinks = wp_parse_id_list( $parsed_args['include'] );
		if ( count( $inclinks ) ) {
			foreach ( $inclinks as $inclink ) {
				if ( empty( $inclusions ) ) {
					$inclusions = ' AND ( link_id = ' . $inclink . ' ';
				} else {
					$inclusions .= ' OR link_id = ' . $inclink . ' ';
				}
			}
		}
	}
	if ( ! empty( $inclusions ) ) {
		$inclusions .= ')';
	}

	$exclusions = '';
	if ( ! empty( $parsed_args['exclude'] ) ) {
		$exlinks = wp_parse_id_list( $parsed_args['exclude'] );
		if ( count( $exlinks ) ) {
			foreach ( $exlinks as $exlink ) {
				if ( empty( $exclusions ) ) {
					$exclusions = ' AND ( link_id <> ' . $exlink . ' ';
				} else {
					$exclusions .= ' AND link_id <> ' . $exlink . ' ';
				}
			}
		}
	}
	if ( ! empty( $exclusions ) ) {
		$exclusions .= ')';
	}

	if ( ! empty( $parsed_args['category_name'] ) ) {
		$parsed_args['category'] = get_term_by( 'name', $parsed_args['category_name'], 'link_category' );
		if ( $parsed_args['category'] ) {
			$parsed_args['category'] = $parsed_args['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(), $parsed_args );
		}
	}

	$search = '';
	if ( ! empty( $parsed_args['search'] ) ) {
		$like   = '%' . $wpdb->esc_like( $parsed_args['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( $parsed_args['category'] ) ) {
		$incategories = wp_parse_id_list( $parsed_args['category'] );
		if ( count( $incategories ) ) {
			foreach ( $incategories as $incat ) {
				if ( empty( $category_query ) ) {
					$category_query = ' AND ( tt.term_id = ' . $incat . ' ';
				} else {
					$category_query .= ' OR tt.term_id = ' . $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 ( $parsed_args['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 = ( $parsed_args['show_updated'] ) ? ', UNIX_TIMESTAMP(link_updated) AS link_updated_f ' : '';

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

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

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

	$visible = '';
	if ( $parsed_args['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 ( -1 != $parsed_args['limit'] ) {
		$query .= ' LIMIT ' . absint( $parsed_args['limit'] );
	}

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

	if ( 'rand()' !== $orderby ) {
		$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, $parsed_args );
}