Improve Story Discoverability on Frontend

includes/Discovery.php

@@ -0,0 +1,310 @@
+<?php
+/**
+ * Class Discovery.
+ *
+ * Responsible for improved discovery of stories on the web.
+ *
+ * @package   Google\Web_Stories
+ * @copyright 2020 Google LLC
+ * @license   https://www.apache.org/licenses/LICENSE-2.0 Apache License 2.0
+ * @link      https://github.com/google/web-stories-wp
+ */
+
+/**
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Google\Web_Stories;
+
+use Google\Web_Stories\REST_API\Stories_Controller;
+use WP_Post;
+
+/**
+ * Discovery class.
+ */
+class Discovery {
+	/**
+	 * Initialize discovery functionality.
+	 *
+	 * @return void
+	 */
+	public function init() {
+		add_action(
+			'web_stories_story_head',
+			static function () {
+				// Theme support for title-tag is implied for stories. See _wp_render_title_tag().
+				echo '<title>' . esc_html( wp_get_document_title() ) . '</title>' . "\n";
+			},
+			1
+		);
+
+		add_action( 'web_stories_story_head', [ $this, 'print_schemaorg_metadata' ] );
+		add_action( 'web_stories_story_head', [ $this, 'print_open_graph_metadata' ] );
+		add_action( 'web_stories_story_head', [ $this, 'print_twitter_metadata' ] );
+
+		// @todo Check if there's something to skip in the new version.
+		add_action( 'web_stories_story_head', 'rest_output_link_wp_head', 10, 0 );
+		add_action( 'web_stories_story_head', 'wp_resource_hints', 2 );
+		add_action( 'web_stories_story_head', 'feed_links', 2 );
+		add_action( 'web_stories_story_head', 'feed_links_extra', 3 );
+		add_action( 'web_stories_story_head', 'rsd_link' );
+		add_action( 'web_stories_story_head', 'wlwmanifest_link' );
+		add_action( 'web_stories_story_head', 'adjacent_posts_rel_link_wp_head', 10, 0 );
+		add_action( 'web_stories_story_head', 'noindex', 1 );
+		add_action( 'web_stories_story_head', 'wp_generator' );
+		add_action( 'web_stories_story_head', 'rel_canonical' );
+		add_action( 'web_stories_story_head', 'wp_shortlink_wp_head', 10, 0 );
+		add_action( 'web_stories_story_head', 'wp_site_icon', 99 );
+		add_action( 'web_stories_story_head', 'wp_oembed_add_discovery_links' );
+	}
+
+	/**
+	 * Prints the schema.org metadata on the single story template.
+	 *
+	 * @return void
+	 */
+	public function print_schemaorg_metadata() {
+		$metadata = $this->get_schemaorg_metadata();
+
+		?>
+		<script type="application/ld+json"><?php echo wp_json_encode( $metadata, JSON_UNESCAPED_UNICODE ); ?></script>
+		<?php
+	}
+
+	/**
+	 * Get schema.org metadata for the current query.
+	 *
+	 * @see https://developers.google.com/search/docs/guides/enable-web-stories
+	 *
+	 * @return array $metadata All schema.org metadata for the post.
+	 */
+	protected function get_schemaorg_metadata() {
+		$publisher = self::get_publisher_data();
+
+		$metadata = [
+			'@context'  => 'http://schema.org',
+			'publisher' => [
+				'@type' => 'Organization',
+				'name'  => $publisher['name'],
+				'logo'  => $publisher['logo'],
+			],
+		];
+
+		/**
+		 * We're expecting a post object.
+		 *
+		 * @var WP_Post $post
+		 */
+		$post = get_queried_object();
+
+		if ( $post instanceof WP_Post ) {
+			$metadata = array_merge(
+				$metadata,
+				[
+					'@type'            => 'Article',
+					'mainEntityOfPage' => get_permalink( $post ),
+					'headline'         => get_the_title( $post ),
+					'datePublished'    => mysql2date( 'c', $post->post_date_gmt, false ),
+					'dateModified'     => mysql2date( 'c', $post->post_modified_gmt, false ),
+				]
+			);
+
+			$post_author = get_userdata( (int) $post->post_author );
+
+			if ( $post_author ) {
+				$metadata['author'] = [
+					'@type' => 'Person',
+					'name'  => html_entity_decode( $post_author->display_name, ENT_QUOTES, get_bloginfo( 'charset' ) ),
+				];
+			}
+
+			if ( has_post_thumbnail( $post->ID ) ) {
+				$metadata['image'] = wp_get_attachment_image_url( (int) get_post_thumbnail_id( $post->ID ), 'full' );
+			}
+		}
+
+		/**
+		 * Filters the schema.org metadata for a given story.
+		 *
+		 * @param array $metadata The structured data.
+		 * @param WP_Post $post The current post object.
+		 */
+		return apply_filters( 'web_stories_story_schema_metadata', $metadata, $post );
+	}
+
+	/**
+	 * Prints Open Graph metadata.
+	 *
+	 * @return void
+	 */
+	public function print_open_graph_metadata() {
+		?>
+		<meta property="og:locale" content="<?php echo esc_attr( get_bloginfo( 'language' ) ); ?>" />
+		<meta property="og:type" content="article" />
+		<meta property="og:title" content="<?php the_title_attribute(); ?>" />
+		<meta property="og:url" content="<?php the_permalink(); ?>">
+		<meta property="og:site_name" content="<?php echo esc_attr( get_bloginfo( 'name' ) ); ?>">
+		<?php
+		if ( ! get_post() ) {
+			return;
+		}
+		?>
+		<meta property="article:published_time" content="<?php echo esc_attr( (string) get_the_date( 'c' ) ); ?>">
+		<meta property="article:modified_time" content="<?php echo esc_attr( (string) get_the_modified_date( 'c' ) ); ?>">
+		<?php
+
+		if ( ! has_post_thumbnail() ) {
+			return;
+		}
+
+		$poster = wp_get_attachment_image_src( (int) get_post_thumbnail_id(), 'full' );
+
+		if ( ! $poster ) {
+			return;
+		}
+		?>
+		<meta property="og:image" content="<?php echo esc_url( $poster[0] ); ?>">
+		<meta property="og:image:width" content="<?php echo esc_attr( $poster[1] ); ?>">
+		<meta property="og:image:height" content="<?php echo esc_attr( $poster[2] ); ?>">
+		<?php
+	}
+
+	/**
+	 * Prints Twitter card metadata.
+	 *
+	 * @return void
+	 */
+	public function print_twitter_metadata() {
+		?>
+		<meta name="twitter:card" content="summary_large_image" />
+		<?php
+
+		if ( ! has_post_thumbnail() ) {
+			return;
+		}
+
+		$poster = wp_get_attachment_image_url( (int) get_post_thumbnail_id(), Media::STORY_POSTER_IMAGE_SIZE );
+
+		if ( ! $poster ) {
+			return;
+		}
+		?>
+		<meta property="twtter:image" content="<?php echo esc_url( $poster ); ?>">
+		<?php
+	}
+
+	/**
+	 * Gets a valid publisher logo URL. Loops through sizes and looks for a square image.
+	 *
+	 * @param integer $image_id Attachment ID.
+	 *
+	 * @return string|false Either the URL or false if error.
+	 */
+	private static function get_valid_publisher_image( $image_id ) {
+		$logo_image_url = false;
+
+		// Get metadata for finding a square image.
+		$metadata = wp_get_attachment_metadata( $image_id );
+		if ( empty( $metadata ) ) {
+			return $logo_image_url;
+		}
+		// First lets check if the image is square by default.
+		$fullsize_img = wp_get_attachment_image_src( $image_id, 'full', false );
+		if ( $metadata['width'] === $metadata['height'] && is_array( $fullsize_img ) ) {
+			return array_shift( $fullsize_img );
+		}
+
+		if ( empty( $metadata['sizes'] ) ) {
+			return $logo_image_url;
+		}
+
+		// Loop through other size to find a square image.
+		foreach ( $metadata['sizes'] as $size ) {
+			if ( $size['width'] === $size['height'] && $size['width'] >= 96 ) {
+				$logo_img = wp_get_attachment_image_src( $image_id, [ $size['width'], $size['height'] ], false );
+				if ( is_array( $logo_img ) ) {
+					return array_shift( $logo_img );
+				}
+			}
+		}
+
+		// If a square image was not found, return the full size nevertheless,
+		// the editor should take care of warning about incorrect size.
+		return is_array( $fullsize_img ) ? array_shift( $fullsize_img ) : false;
+	}
+
+	/**
+	 * Get the publisher logo.
+	 *
+	 * @link https://developers.google.com/search/docs/data-types/article#logo-guidelines
+	 * @link https://amp.dev/documentation/components/amp-story/#publisher-logo-src-guidelines
+	 *
+	 * @return string Publisher logo image URL. WordPress logo if no site icon or custom logo defined, and no logo provided via 'amp_site_icon_url' filter.
+	 */
+	public static function get_publisher_logo() {
+		$logo_image_url = null;
+
+		$publisher_logo_settings = get_option( Stories_Controller::PUBLISHER_LOGOS_OPTION, [] );
+		$has_publisher_logo      = ! empty( $publisher_logo_settings['active'] );
+		if ( $has_publisher_logo ) {
+			$publisher_logo_id = absint( $publisher_logo_settings['active'] );
+			$logo_image_url    = self::get_valid_publisher_image( $publisher_logo_id );
+		}
+
+		// @todo Once we are enforcing setting publisher logo in the editor, we shouldn't need the fallback options.
+		// Currently, it's marked as required but that's not actually enforced.
+
+		// Finding fallback image.
+		$custom_logo_id = get_theme_mod( 'custom_logo' );
+		if ( empty( $logo_image_url ) && has_custom_logo() && $custom_logo_id ) {
+			$logo_image_url = self::get_valid_publisher_image( $custom_logo_id );
+		}
+
+		// Try Site Icon, though it is not ideal for non-Story because it should be square.
+		$site_icon_id = get_option( 'site_icon' );
+		if ( empty( $logo_image_url ) && $site_icon_id ) {
+			$logo_image_url = self::get_valid_publisher_image( $site_icon_id );
+		}
+
+		// Fallback to serving the WordPress logo.
+		if ( empty( $logo_image_url ) ) {
+			$logo_image_url = WEBSTORIES_PLUGIN_DIR_URL . 'assets/images/fallback-wordpress-publisher-logo.png';
+		}
+
+		/**
+		 * Filters the publisher's logo.
+		 *
+		 * This should point to a square image.
+		 *
+		 * @param string $logo_image_url URL to the publisher's logo.
+		 */
+		return apply_filters( 'web_stories_publisher_logo', $logo_image_url );
+	}
+
+	/**
+	 * Returns the publisher data.
+	 *
+	 * @return array Publisher name and logo.
+	 */
+	public static function get_publisher_data() {
+		$publisher      = get_bloginfo( 'name' );
+		$publisher_logo = self::get_publisher_logo();
+
+		return [
+			'name' => $publisher,
+			'logo' => $publisher_logo,
+		];
+	}
+}

includes/Media.php

@@ -319,4 +319,77 @@ public static function delete_video_poster( $attachment_id ) {
 			wp_delete_attachment( $post_id, true );
 		}
 	}
+
+	/**
+	 * Returns a list of allowed file types.
+	 *
+	 * @return array List of allowed file types.
+	 */
+	public static function get_allowed_file_types() {
+		$allowed_mime_types = self::get_allowed_mime_types();
+		$mime_types         = [];
+
+		foreach ( $allowed_mime_types as $mimes ) {
+			// Otherwise this throws a warning on PHP < 7.3.
+			if ( ! empty( $mimes ) ) {
+				array_push( $mime_types, ...$mimes );
+			}
+		}
+
+		$allowed_file_types = [];
+		$all_mime_types     = wp_get_mime_types();
+
+		foreach ( $all_mime_types as $ext => $mime ) {
+			if ( in_array( $mime, $mime_types, true ) ) {
+				array_push( $allowed_file_types, ...explode( '|', $ext ) );
+			}
+		}
+		sort( $allowed_file_types );
+
+		return $allowed_file_types;
+	}
+
+	/**
+	 * Returns a list of allowed mime types per media type (image, audio, video).
+	 *
+	 * @return array List of allowed mime types.
+	 */
+	public static function get_allowed_mime_types() {
+		$default_allowed_mime_types = [
+			'image' => [
+				'image/png',
+				'image/jpeg',
+				'image/jpg',
+				'image/gif',
+			],
+			'audio' => [], // todo: support audio uploads.
+			'video' => [
+				'video/mp4',
+				'video/webm',
+			],
+		];
+
+		/**
+		 * Filter list of allowed mime types.
+		 *
+		 * This can be used to add additionally supported formats, for example by plugins
+		 * that do video transcoding.
+		 *
+		 * @since 1.3
+		 *
+		 * @param array $default_allowed_mime_types Associative array of allowed mime types per media type (image, audio, video).
+		 */
+		$allowed_mime_types = apply_filters( 'web_stories_allowed_mime_types', $default_allowed_mime_types );
+
+		foreach ( array_keys( $default_allowed_mime_types ) as $media_type ) {
+			if ( ! is_array( $allowed_mime_types[ $media_type ] ) || empty( $allowed_mime_types[ $media_type ] ) ) {
+				$allowed_mime_types[ $media_type ] = $default_allowed_mime_types[ $media_type ];
+			}
+
+			// Only add currently supported mime types.
+			$allowed_mime_types[ $media_type ] = array_values( array_intersect( $allowed_mime_types[ $media_type ], wp_get_mime_types() ) );
+		}
+
+		return $allowed_mime_types;
+	}
 }