669 lines
		
	
	
		
			20 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
			
		
		
	
	
			669 lines
		
	
	
		
			20 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
| <?php
 | |
| /**
 | |
|  * REST API: WP_REST_URL_Details_Controller class
 | |
|  *
 | |
|  * @package WordPress
 | |
|  * @subpackage REST_API
 | |
|  * @since 5.9.0
 | |
|  */
 | |
| 
 | |
| /**
 | |
|  * Controller which provides REST endpoint for retrieving information
 | |
|  * from a remote site's HTML response.
 | |
|  *
 | |
|  * @since 5.9.0
 | |
|  *
 | |
|  * @see WP_REST_Controller
 | |
|  */
 | |
| class WP_REST_URL_Details_Controller extends WP_REST_Controller {
 | |
| 
 | |
| 	/**
 | |
| 	 * Constructs the controller.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 */
 | |
| 	public function __construct() {
 | |
| 		$this->namespace = 'wp-block-editor/v1';
 | |
| 		$this->rest_base = 'url-details';
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Registers the necessary REST API routes.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 */
 | |
| 	public function register_routes() {
 | |
| 		register_rest_route(
 | |
| 			$this->namespace,
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| 			'/' . $this->rest_base,
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| 			array(
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| 				array(
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| 					'methods'             => WP_REST_Server::READABLE,
 | |
| 					'callback'            => array( $this, 'parse_url_details' ),
 | |
| 					'args'                => array(
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| 						'url' => array(
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| 							'required'          => true,
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| 							'description'       => __( 'The URL to process.' ),
 | |
| 							'validate_callback' => 'wp_http_validate_url',
 | |
| 							'sanitize_callback' => 'sanitize_url',
 | |
| 							'type'              => 'string',
 | |
| 							'format'            => 'uri',
 | |
| 						),
 | |
| 					),
 | |
| 					'permission_callback' => array( $this, 'permissions_check' ),
 | |
| 					'schema'              => array( $this, 'get_public_item_schema' ),
 | |
| 				),
 | |
| 			)
 | |
| 		);
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Retrieves the item's schema, conforming to JSON Schema.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @return array Item schema data.
 | |
| 	 */
 | |
| 	public function get_item_schema() {
 | |
| 		if ( $this->schema ) {
 | |
| 			return $this->add_additional_fields_schema( $this->schema );
 | |
| 		}
 | |
| 
 | |
| 		$this->schema = array(
 | |
| 			'$schema'    => 'http://json-schema.org/draft-04/schema#',
 | |
| 			'title'      => 'url-details',
 | |
| 			'type'       => 'object',
 | |
| 			'properties' => array(
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| 				'title'       => array(
 | |
| 					'description' => sprintf(
 | |
| 						/* translators: %s: HTML title tag. */
 | |
| 						__( 'The contents of the %s element from the URL.' ),
 | |
| 						'<title>'
 | |
| 					),
 | |
| 					'type'        => 'string',
 | |
| 					'context'     => array( 'view', 'edit', 'embed' ),
 | |
| 					'readonly'    => true,
 | |
| 				),
 | |
| 				'icon'        => array(
 | |
| 					'description' => sprintf(
 | |
| 						/* translators: %s: HTML link tag. */
 | |
| 						__( 'The favicon image link of the %s element from the URL.' ),
 | |
| 						'<link rel="icon">'
 | |
| 					),
 | |
| 					'type'        => 'string',
 | |
| 					'format'      => 'uri',
 | |
| 					'context'     => array( 'view', 'edit', 'embed' ),
 | |
| 					'readonly'    => true,
 | |
| 				),
 | |
| 				'description' => array(
 | |
| 					'description' => sprintf(
 | |
| 						/* translators: %s: HTML meta tag. */
 | |
| 						__( 'The content of the %s element from the URL.' ),
 | |
| 						'<meta name="description">'
 | |
| 					),
 | |
| 					'type'        => 'string',
 | |
| 					'context'     => array( 'view', 'edit', 'embed' ),
 | |
| 					'readonly'    => true,
 | |
| 				),
 | |
| 				'image'       => array(
 | |
| 					'description' => sprintf(
 | |
| 						/* translators: 1: HTML meta tag, 2: HTML meta tag. */
 | |
| 						__( 'The Open Graph image link of the %1$s or %2$s element from the URL.' ),
 | |
| 						'<meta property="og:image">',
 | |
| 						'<meta property="og:image:url">'
 | |
| 					),
 | |
| 					'type'        => 'string',
 | |
| 					'format'      => 'uri',
 | |
| 					'context'     => array( 'view', 'edit', 'embed' ),
 | |
| 					'readonly'    => true,
 | |
| 				),
 | |
| 			),
 | |
| 		);
 | |
| 
 | |
| 		return $this->add_additional_fields_schema( $this->schema );
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Retrieves the contents of the title tag from the HTML response.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param WP_REST_Request $request Full details about the request.
 | |
| 	 * @return WP_REST_Response|WP_Error The parsed details as a response object. WP_Error if there are errors.
 | |
| 	 */
 | |
| 	public function parse_url_details( $request ) {
 | |
| 		$url = untrailingslashit( $request['url'] );
 | |
| 
 | |
| 		if ( empty( $url ) ) {
 | |
| 			return new WP_Error( 'rest_invalid_url', __( 'Invalid URL' ), array( 'status' => 404 ) );
 | |
| 		}
 | |
| 
 | |
| 		// Transient per URL.
 | |
| 		$cache_key = $this->build_cache_key_for_url( $url );
 | |
| 
 | |
| 		// Attempt to retrieve cached response.
 | |
| 		$cached_response = $this->get_cache( $cache_key );
 | |
| 
 | |
| 		if ( ! empty( $cached_response ) ) {
 | |
| 			$remote_url_response = $cached_response;
 | |
| 		} else {
 | |
| 			$remote_url_response = $this->get_remote_url( $url );
 | |
| 
 | |
| 			// Exit if we don't have a valid body or it's empty.
 | |
| 			if ( is_wp_error( $remote_url_response ) || empty( $remote_url_response ) ) {
 | |
| 				return $remote_url_response;
 | |
| 			}
 | |
| 
 | |
| 			// Cache the valid response.
 | |
| 			$this->set_cache( $cache_key, $remote_url_response );
 | |
| 		}
 | |
| 
 | |
| 		$html_head     = $this->get_document_head( $remote_url_response );
 | |
| 		$meta_elements = $this->get_meta_with_content_elements( $html_head );
 | |
| 
 | |
| 		$data = $this->add_additional_fields_to_object(
 | |
| 			array(
 | |
| 				'title'       => $this->get_title( $html_head ),
 | |
| 				'icon'        => $this->get_icon( $html_head, $url ),
 | |
| 				'description' => $this->get_description( $meta_elements ),
 | |
| 				'image'       => $this->get_image( $meta_elements, $url ),
 | |
| 			),
 | |
| 			$request
 | |
| 		);
 | |
| 
 | |
| 		// Wrap the data in a response object.
 | |
| 		$response = rest_ensure_response( $data );
 | |
| 
 | |
| 		/**
 | |
| 		 * Filters the URL data for the response.
 | |
| 		 *
 | |
| 		 * @since 5.9.0
 | |
| 		 *
 | |
| 		 * @param WP_REST_Response $response            The response object.
 | |
| 		 * @param string           $url                 The requested URL.
 | |
| 		 * @param WP_REST_Request  $request             Request object.
 | |
| 		 * @param string           $remote_url_response HTTP response body from the remote URL.
 | |
| 		 */
 | |
| 		return apply_filters( 'rest_prepare_url_details', $response, $url, $request, $remote_url_response );
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Checks whether a given request has permission to read remote URLs.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @return WP_Error|bool True if the request has permission, else WP_Error.
 | |
| 	 */
 | |
| 	public function permissions_check() {
 | |
| 		if ( current_user_can( 'edit_posts' ) ) {
 | |
| 			return true;
 | |
| 		}
 | |
| 
 | |
| 		foreach ( get_post_types( array( 'show_in_rest' => true ), 'objects' ) as $post_type ) {
 | |
| 			if ( current_user_can( $post_type->cap->edit_posts ) ) {
 | |
| 				return true;
 | |
| 			}
 | |
| 		}
 | |
| 
 | |
| 		return new WP_Error(
 | |
| 			'rest_cannot_view_url_details',
 | |
| 			__( 'Sorry, you are not allowed to process remote URLs.' ),
 | |
| 			array( 'status' => rest_authorization_required_code() )
 | |
| 		);
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Retrieves the document title from a remote URL.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $url The website URL whose HTML to access.
 | |
| 	 * @return string|WP_Error The HTTP response from the remote URL on success.
 | |
| 	 *                         WP_Error if no response or no content.
 | |
| 	 */
 | |
| 	private function get_remote_url( $url ) {
 | |
| 
 | |
| 		/*
 | |
| 		 * Provide a modified UA string to workaround web properties which block WordPress "Pingbacks".
 | |
| 		 * Why? The UA string used for pingback requests contains `WordPress/` which is very similar
 | |
| 		 * to that used as the default UA string by the WP HTTP API. Therefore requests from this
 | |
| 		 * REST endpoint are being unintentionally blocked as they are misidentified as pingback requests.
 | |
| 		 * By slightly modifying the UA string, but still retaining the "WordPress" identification (via "WP")
 | |
| 		 * we are able to work around this issue.
 | |
| 		 * Example UA string: `WP-URLDetails/5.9-alpha-51389 (+http://localhost:8888)`.
 | |
| 		*/
 | |
| 		$modified_user_agent = 'WP-URLDetails/' . get_bloginfo( 'version' ) . ' (+' . get_bloginfo( 'url' ) . ')';
 | |
| 
 | |
| 		$args = array(
 | |
| 			'limit_response_size' => 150 * KB_IN_BYTES,
 | |
| 			'user-agent'          => $modified_user_agent,
 | |
| 		);
 | |
| 
 | |
| 		/**
 | |
| 		 * Filters the HTTP request args for URL data retrieval.
 | |
| 		 *
 | |
| 		 * Can be used to adjust response size limit and other WP_Http::request() args.
 | |
| 		 *
 | |
| 		 * @since 5.9.0
 | |
| 		 *
 | |
| 		 * @param array  $args Arguments used for the HTTP request.
 | |
| 		 * @param string $url  The attempted URL.
 | |
| 		 */
 | |
| 		$args = apply_filters( 'rest_url_details_http_request_args', $args, $url );
 | |
| 
 | |
| 		$response = wp_safe_remote_get( $url, $args );
 | |
| 
 | |
| 		if ( WP_Http::OK !== wp_remote_retrieve_response_code( $response ) ) {
 | |
| 			// Not saving the error response to cache since the error might be temporary.
 | |
| 			return new WP_Error(
 | |
| 				'no_response',
 | |
| 				__( 'URL not found. Response returned a non-200 status code for this URL.' ),
 | |
| 				array( 'status' => WP_Http::NOT_FOUND )
 | |
| 			);
 | |
| 		}
 | |
| 
 | |
| 		$remote_body = wp_remote_retrieve_body( $response );
 | |
| 
 | |
| 		if ( empty( $remote_body ) ) {
 | |
| 			return new WP_Error(
 | |
| 				'no_content',
 | |
| 				__( 'Unable to retrieve body from response at this URL.' ),
 | |
| 				array( 'status' => WP_Http::NOT_FOUND )
 | |
| 			);
 | |
| 		}
 | |
| 
 | |
| 		return $remote_body;
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Parses the title tag contents from the provided HTML.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $html The HTML from the remote website at URL.
 | |
| 	 * @return string The title tag contents on success. Empty string if not found.
 | |
| 	 */
 | |
| 	private function get_title( $html ) {
 | |
| 		$pattern = '#<title[^>]*>(.*?)<\s*/\s*title>#is';
 | |
| 		preg_match( $pattern, $html, $match_title );
 | |
| 
 | |
| 		if ( empty( $match_title[1] ) || ! is_string( $match_title[1] ) ) {
 | |
| 			return '';
 | |
| 		}
 | |
| 
 | |
| 		$title = trim( $match_title[1] );
 | |
| 
 | |
| 		return $this->prepare_metadata_for_output( $title );
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Parses the site icon from the provided HTML.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $html The HTML from the remote website at URL.
 | |
| 	 * @param string $url  The target website URL.
 | |
| 	 * @return string The icon URI on success. Empty string if not found.
 | |
| 	 */
 | |
| 	private function get_icon( $html, $url ) {
 | |
| 		// Grab the icon's link element.
 | |
| 		$pattern = '#<link\s[^>]*rel=(?:[\"\']??)\s*(?:icon|shortcut icon|icon shortcut)\s*(?:[\"\']??)[^>]*\/?>#isU';
 | |
| 		preg_match( $pattern, $html, $element );
 | |
| 		if ( empty( $element[0] ) || ! is_string( $element[0] ) ) {
 | |
| 			return '';
 | |
| 		}
 | |
| 		$element = trim( $element[0] );
 | |
| 
 | |
| 		// Get the icon's href value.
 | |
| 		$pattern = '#href=([\"\']??)([^\" >]*?)\\1[^>]*#isU';
 | |
| 		preg_match( $pattern, $element, $icon );
 | |
| 		if ( empty( $icon[2] ) || ! is_string( $icon[2] ) ) {
 | |
| 			return '';
 | |
| 		}
 | |
| 		$icon = trim( $icon[2] );
 | |
| 
 | |
| 		// If the icon is a data URL, return it.
 | |
| 		$parsed_icon = parse_url( $icon );
 | |
| 		if ( isset( $parsed_icon['scheme'] ) && 'data' === $parsed_icon['scheme'] ) {
 | |
| 			return $icon;
 | |
| 		}
 | |
| 
 | |
| 		// Attempt to convert relative URLs to absolute.
 | |
| 		if ( ! is_string( $url ) || '' === $url ) {
 | |
| 			return $icon;
 | |
| 		}
 | |
| 		$parsed_url = parse_url( $url );
 | |
| 		if ( isset( $parsed_url['scheme'] ) && isset( $parsed_url['host'] ) ) {
 | |
| 			$root_url = $parsed_url['scheme'] . '://' . $parsed_url['host'] . '/';
 | |
| 			$icon     = WP_Http::make_absolute_url( $icon, $root_url );
 | |
| 		}
 | |
| 
 | |
| 		return $icon;
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Parses the meta description from the provided HTML.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param array $meta_elements {
 | |
| 	 *     A multi-dimensional indexed array on success, else empty array.
 | |
| 	 *
 | |
| 	 *     @type string[] $0 Meta elements with a content attribute.
 | |
| 	 *     @type string[] $1 Content attribute's opening quotation mark.
 | |
| 	 *     @type string[] $2 Content attribute's value for each meta element.
 | |
| 	 * }
 | |
| 	 * @return string The meta description contents on success. Empty string if not found.
 | |
| 	 */
 | |
| 	private function get_description( $meta_elements ) {
 | |
| 		// Bail out if there are no meta elements.
 | |
| 		if ( empty( $meta_elements[0] ) ) {
 | |
| 			return '';
 | |
| 		}
 | |
| 
 | |
| 		$description = $this->get_metadata_from_meta_element(
 | |
| 			$meta_elements,
 | |
| 			'name',
 | |
| 			'(?:description|og:description)'
 | |
| 		);
 | |
| 
 | |
| 		// Bail out if description not found.
 | |
| 		if ( '' === $description ) {
 | |
| 			return '';
 | |
| 		}
 | |
| 
 | |
| 		return $this->prepare_metadata_for_output( $description );
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Parses the Open Graph (OG) Image from the provided HTML.
 | |
| 	 *
 | |
| 	 * See: https://ogp.me/.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param array  $meta_elements {
 | |
| 	 *     A multi-dimensional indexed array on success, else empty array.
 | |
| 	 *
 | |
| 	 *     @type string[] $0 Meta elements with a content attribute.
 | |
| 	 *     @type string[] $1 Content attribute's opening quotation mark.
 | |
| 	 *     @type string[] $2 Content attribute's value for each meta element.
 | |
| 	 * }
 | |
| 	 * @param string $url The target website URL.
 | |
| 	 * @return string The OG image on success. Empty string if not found.
 | |
| 	 */
 | |
| 	private function get_image( $meta_elements, $url ) {
 | |
| 		$image = $this->get_metadata_from_meta_element(
 | |
| 			$meta_elements,
 | |
| 			'property',
 | |
| 			'(?:og:image|og:image:url)'
 | |
| 		);
 | |
| 
 | |
| 		// Bail out if image not found.
 | |
| 		if ( '' === $image ) {
 | |
| 			return '';
 | |
| 		}
 | |
| 
 | |
| 		// Attempt to convert relative URLs to absolute.
 | |
| 		$parsed_url = parse_url( $url );
 | |
| 		if ( isset( $parsed_url['scheme'] ) && isset( $parsed_url['host'] ) ) {
 | |
| 			$root_url = $parsed_url['scheme'] . '://' . $parsed_url['host'] . '/';
 | |
| 			$image    = WP_Http::make_absolute_url( $image, $root_url );
 | |
| 		}
 | |
| 
 | |
| 		return $image;
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Prepares the metadata by:
 | |
| 	 *    - stripping all HTML tags and tag entities.
 | |
| 	 *    - converting non-tag entities into characters.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $metadata The metadata content to prepare.
 | |
| 	 * @return string The prepared metadata.
 | |
| 	 */
 | |
| 	private function prepare_metadata_for_output( $metadata ) {
 | |
| 		$metadata = html_entity_decode( $metadata, ENT_QUOTES, get_bloginfo( 'charset' ) );
 | |
| 		$metadata = wp_strip_all_tags( $metadata );
 | |
| 		return $metadata;
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Utility function to build cache key for a given URL.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $url The URL for which to build a cache key.
 | |
| 	 * @return string The cache key.
 | |
| 	 */
 | |
| 	private function build_cache_key_for_url( $url ) {
 | |
| 		return 'g_url_details_response_' . md5( $url );
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Utility function to retrieve a value from the cache at a given key.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $key The cache key.
 | |
| 	 * @return mixed The value from the cache.
 | |
| 	 */
 | |
| 	private function get_cache( $key ) {
 | |
| 		return get_site_transient( $key );
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Utility function to cache a given data set at a given cache key.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $key  The cache key under which to store the value.
 | |
| 	 * @param string $data The data to be stored at the given cache key.
 | |
| 	 * @return bool True when transient set. False if not set.
 | |
| 	 */
 | |
| 	private function set_cache( $key, $data = '' ) {
 | |
| 		$ttl = HOUR_IN_SECONDS;
 | |
| 
 | |
| 		/**
 | |
| 		 * Filters the cache expiration.
 | |
| 		 *
 | |
| 		 * Can be used to adjust the time until expiration in seconds for the cache
 | |
| 		 * of the data retrieved for the given URL.
 | |
| 		 *
 | |
| 		 * @since 5.9.0
 | |
| 		 *
 | |
| 		 * @param int $ttl The time until cache expiration in seconds.
 | |
| 		 */
 | |
| 		$cache_expiration = apply_filters( 'rest_url_details_cache_expiration', $ttl );
 | |
| 
 | |
| 		return set_site_transient( $key, $data, $cache_expiration );
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Retrieves the head element section.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $html The string of HTML to parse.
 | |
| 	 * @return string The `<head>..</head>` section on success. Given `$html` if not found.
 | |
| 	 */
 | |
| 	private function get_document_head( $html ) {
 | |
| 		$head_html = $html;
 | |
| 
 | |
| 		// Find the opening `<head>` tag.
 | |
| 		$head_start = strpos( $html, '<head' );
 | |
| 		if ( false === $head_start ) {
 | |
| 			// Didn't find it. Return the original HTML.
 | |
| 			return $html;
 | |
| 		}
 | |
| 
 | |
| 		// Find the closing `</head>` tag.
 | |
| 		$head_end = strpos( $head_html, '</head>' );
 | |
| 		if ( false === $head_end ) {
 | |
| 			// Didn't find it. Find the opening `<body>` tag.
 | |
| 			$head_end = strpos( $head_html, '<body' );
 | |
| 
 | |
| 			// Didn't find it. Return the original HTML.
 | |
| 			if ( false === $head_end ) {
 | |
| 				return $html;
 | |
| 			}
 | |
| 		}
 | |
| 
 | |
| 		// Extract the HTML from opening tag to the closing tag. Then add the closing tag.
 | |
| 		$head_html  = substr( $head_html, $head_start, $head_end );
 | |
| 		$head_html .= '</head>';
 | |
| 
 | |
| 		return $head_html;
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Gets all the meta tag elements that have a 'content' attribute.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param string $html The string of HTML to be parsed.
 | |
| 	 * @return array {
 | |
| 	 *     A multi-dimensional indexed array on success, else empty array.
 | |
| 	 *
 | |
| 	 *     @type string[] $0 Meta elements with a content attribute.
 | |
| 	 *     @type string[] $1 Content attribute's opening quotation mark.
 | |
| 	 *     @type string[] $2 Content attribute's value for each meta element.
 | |
| 	 * }
 | |
| 	 */
 | |
| 	private function get_meta_with_content_elements( $html ) {
 | |
| 		/*
 | |
| 		 * Parse all meta elements with a content attribute.
 | |
| 		 *
 | |
| 		 * Why first search for the content attribute rather than directly searching for name=description element?
 | |
| 		 * tl;dr The content attribute's value will be truncated when it contains a > symbol.
 | |
| 		 *
 | |
| 		 * The content attribute's value (i.e. the description to get) can have HTML in it and be well-formed as
 | |
| 		 * it's a string to the browser. Imagine what happens when attempting to match for the name=description
 | |
| 		 * first. Hmm, if a > or /> symbol is in the content attribute's value, then it terminates the match
 | |
| 		 * as the element's closing symbol. But wait, it's in the content attribute and is not the end of the
 | |
| 		 * element. This is a limitation of using regex. It can't determine "wait a minute this is inside of quotation".
 | |
| 		 * If this happens, what gets matched is not the entire element or all of the content.
 | |
| 		 *
 | |
| 		 * Why not search for the name=description and then content="(.*)"?
 | |
| 		 * The attribute order could be opposite. Plus, additional attributes may exist including being between
 | |
| 		 * the name and content attributes.
 | |
| 		 *
 | |
| 		 * Why not lookahead?
 | |
| 		 * Lookahead is not constrained to stay within the element. The first <meta it finds may not include
 | |
| 		 * the name or content, but rather could be from a different element downstream.
 | |
| 		 */
 | |
| 		$pattern = '#<meta\s' .
 | |
| 
 | |
| 				/*
 | |
| 				 * Allows for additional attributes before the content attribute.
 | |
| 				 * Searches for anything other than > symbol.
 | |
| 				 */
 | |
| 				'[^>]*' .
 | |
| 
 | |
| 				/*
 | |
| 				* Find the content attribute. When found, capture its value (.*).
 | |
| 				*
 | |
| 				* Allows for (a) single or double quotes and (b) whitespace in the value.
 | |
| 				*
 | |
| 				* Why capture the opening quotation mark, i.e. (["\']), and then backreference,
 | |
| 				* i.e \1, for the closing quotation mark?
 | |
| 				* To ensure the closing quotation mark matches the opening one. Why? Attribute values
 | |
| 				* can contain quotation marks, such as an apostrophe in the content.
 | |
| 				*/
 | |
| 				'content=(["\']??)(.*)\1' .
 | |
| 
 | |
| 				/*
 | |
| 				* Allows for additional attributes after the content attribute.
 | |
| 				* Searches for anything other than > symbol.
 | |
| 				*/
 | |
| 				'[^>]*' .
 | |
| 
 | |
| 				/*
 | |
| 				* \/?> searches for the closing > symbol, which can be in either /> or > format.
 | |
| 				* # ends the pattern.
 | |
| 				*/
 | |
| 				'\/?>#' .
 | |
| 
 | |
| 				/*
 | |
| 				* These are the options:
 | |
| 				* - i : case insensitive
 | |
| 				* - s : allows newline characters for the . match (needed for multiline elements)
 | |
| 				* - U means non-greedy matching
 | |
| 				*/
 | |
| 				'isU';
 | |
| 
 | |
| 		preg_match_all( $pattern, $html, $elements );
 | |
| 
 | |
| 		return $elements;
 | |
| 	}
 | |
| 
 | |
| 	/**
 | |
| 	 * Gets the metadata from a target meta element.
 | |
| 	 *
 | |
| 	 * @since 5.9.0
 | |
| 	 *
 | |
| 	 * @param array  $meta_elements {
 | |
| 	 *     A multi-dimensional indexed array on success, else empty array.
 | |
| 	 *
 | |
| 	 *     @type string[] $0 Meta elements with a content attribute.
 | |
| 	 *     @type string[] $1 Content attribute's opening quotation mark.
 | |
| 	 *     @type string[] $2 Content attribute's value for each meta element.
 | |
| 	 * }
 | |
| 	 * @param string $attr       Attribute that identifies the element with the target metadata.
 | |
| 	 * @param string $attr_value The attribute's value that identifies the element with the target metadata.
 | |
| 	 * @return string The metadata on success. Empty string if not found.
 | |
| 	 */
 | |
| 	private function get_metadata_from_meta_element( $meta_elements, $attr, $attr_value ) {
 | |
| 		// Bail out if there are no meta elements.
 | |
| 		if ( empty( $meta_elements[0] ) ) {
 | |
| 			return '';
 | |
| 		}
 | |
| 
 | |
| 		$metadata = '';
 | |
| 		$pattern  = '#' .
 | |
| 				/*
 | |
| 				 * Target this attribute and value to find the metadata element.
 | |
| 				 *
 | |
| 				 * Allows for (a) no, single, double quotes and (b) whitespace in the value.
 | |
| 				 *
 | |
| 				 * Why capture the opening quotation mark, i.e. (["\']), and then backreference,
 | |
| 				 * i.e \1, for the closing quotation mark?
 | |
| 				 * To ensure the closing quotation mark matches the opening one. Why? Attribute values
 | |
| 				 * can contain quotation marks, such as an apostrophe in the content.
 | |
| 				 */
 | |
| 				$attr . '=([\"\']??)\s*' . $attr_value . '\s*\1' .
 | |
| 
 | |
| 				/*
 | |
| 				 * These are the options:
 | |
| 				 * - i : case insensitive
 | |
| 				 * - s : allows newline characters for the . match (needed for multiline elements)
 | |
| 				 * - U means non-greedy matching
 | |
| 				 */
 | |
| 				'#isU';
 | |
| 
 | |
| 		// Find the metadata element.
 | |
| 		foreach ( $meta_elements[0] as $index => $element ) {
 | |
| 			preg_match( $pattern, $element, $match );
 | |
| 
 | |
| 			// This is not the metadata element. Skip it.
 | |
| 			if ( empty( $match ) ) {
 | |
| 				continue;
 | |
| 			}
 | |
| 
 | |
| 			/*
 | |
| 			 * Found the metadata element.
 | |
| 			 * Get the metadata from its matching content array.
 | |
| 			 */
 | |
| 			if ( isset( $meta_elements[2][ $index ] ) && is_string( $meta_elements[2][ $index ] ) ) {
 | |
| 				$metadata = trim( $meta_elements[2][ $index ] );
 | |
| 			}
 | |
| 
 | |
| 			break;
 | |
| 		}
 | |
| 
 | |
| 		return $metadata;
 | |
| 	}
 | |
| }
 |