Introduce meta description presenter

composer.json

@@ -139,7 +139,8 @@
 		],
 		"post-install-cmd": [
 			"xrstf\\Composer52\\Generator::onPostInstallCmd",
-			"Yoast\\WP\\Free\\Composer\\Actions::prefix_dependencies"
+			"Yoast\\WP\\Free\\Composer\\Actions::prefix_dependencies",
+			"Yoast\\WP\\Free\\Composer\\Actions::compile_dependency_injection_container"
 		],
 		"post-update-cmd": [
 			"xrstf\\Composer52\\Generator::onPostInstallCmd"

config/dependency-injection/services.php

@@ -8,6 +8,7 @@
 namespace Yoast\WP\Free\Dependency_Injection;
 
 use Symfony\Component\DependencyInjection\Definition;
+use WPSEO_Replace_Vars;
 use Yoast\WP\Free\Repositories\Indexable_Repository;
 use Yoast\WP\Free\Repositories\Primary_Term_Repository;
 use Yoast\WP\Free\Repositories\SEO_Links_Repository;
@@ -18,7 +19,9 @@
 
 // WordPress factory functions.
 $container->register( 'wpdb', 'wpdb' )->setFactory( [ Wrapper::class, 'get_wpdb' ] );
-$container->register( 'wp_query', 'WP_Query' )->setFactory( [ Wrapper::class, 'get_wp_query' ] );
+
+// Legacy classes
+$container->register( WPSEO_Replace_Vars::class, WPSEO_Replace_Vars::class )->setFactory( [ Wrapper::class, 'get_replace_vars' ] );
 
 // Model repository factory functions.
 $container->register( Indexable_Repository::class, Indexable_Repository::class )->setFactory( [ Indexable_Repository::class, 'get_instance' ] )->setAutowired( true );

frontend/class-frontend.php

@@ -11,6 +11,8 @@
  */
 class WPSEO_Frontend {
 
+	const METADESC_PRIORITY = 6;
+
 	/**
 	 * Instance of this class.
 	 *
@@ -93,7 +95,7 @@ protected function __construct() {
 
 		// The head function here calls action wpseo_head, to which we hook all our functionality.
 		add_action( 'wpseo_head', array( $this, 'debug_mark' ), 2 );
-		add_action( 'wpseo_head', array( $this, 'metadesc' ), 6 );
+		add_action( 'wpseo_head', array( $this, 'metadesc' ), self::METADESC_PRIORITY );
 		add_action( 'wpseo_head', array( $this, 'robots' ), 10 );
 		add_action( 'wpseo_head', array( $this, 'canonical' ), 20 );
 		add_action( 'wpseo_head', array( $this, 'adjacent_rel_links' ), 21 );

src/conditionals/front-end-conditional.php

@@ -0,0 +1,21 @@
+<?php
+/**
+ * Yoast SEO plugin file.
+ *
+ * @package Yoast\YoastSEO\Conditionals
+ */
+
+namespace Yoast\WP\Free\Conditionals;
+
+/**
+ * Conditional that is only met when in the admin.
+ */
+class Front_End_Conditional implements Conditional {
+
+	/**
+	 * @inheritdoc
+	 */
+	public function is_met() {
+		return ! \is_admin();
+	}
+}

src/helpers/current-post-helper.php

@@ -0,0 +1,72 @@
+<?php
+/**
+ * A helper object for WordPress posts.
+ *
+ * @package Yoast\YoastSEO\Helpers
+ */
+
+namespace Yoast\WP\Free\Helpers;
+
+/**
+ * Class Current_Post_Helper
+ */
+class Current_Post_Helper {
+
+	/**
+	 * Checks if the currently opened page is a simple page.
+	 *
+	 * @return bool Whether the currently opened page is a simple page.
+	 */
+	public function is_simple_page() {
+		return self::get_simple_page_id() > 0;
+	}
+
+	/**
+	 * Returns the id of the currently opened page.
+	 *
+	 * @return int The id of the currently opened page.
+	 */
+	public function get_simple_page_id() {
+		if ( \is_singular() ) {
+			return \get_the_ID();
+		}
+
+		if ( self::is_posts_page() ) {
+			return \get_option( 'page_for_posts' );
+		}
+
+		/**
+		 * Filter: Allow changing the default page id.
+		 *
+		 * @api int $page_id The default page id.
+		 */
+		return \apply_filters( 'wpseo_frontend_page_type_simple_page_id', 0 );
+	}
+
+	/**
+	 * Determine whether this is the homepage and shows posts.
+	 *
+	 * @return bool Whether or not the current page is the homepage that displays posts.
+	 */
+	public function is_home_posts_page() {
+		return ( \is_home() && \get_option( 'show_on_front' ) === 'posts' );
+	}
+
+	/**
+	 * Determine whether this is the static frontpage.
+	 *
+	 * @return bool Whether or not the current page is a static frontpage.
+	 */
+	public function is_home_static_page() {
+		return ( \is_front_page() && \get_option( 'show_on_front' ) === 'page' && \is_page( \get_option( 'page_on_front' ) ) );
+	}
+
+	/**
+	 * Determine whether this is the statically set posts page, when it's not the frontpage.
+	 *
+	 * @return bool Whether or not it's a non-frontpage, statically set posts page.
+	 */
+	public function is_posts_page() {
+		return ( \is_home() && \get_option( 'show_on_front' ) === 'page' );
+	}
+}

src/integrations/front-end-integration.php

@@ -0,0 +1,106 @@
+<?php
+
+namespace Yoast\WP\Free\Integrations;
+
+use Yoast\WP\Free\Conditionals\Front_End_Conditional;
+use Yoast\WP\Free\Conditionals\Indexables_Feature_Flag_Conditional;
+use Yoast\WP\Free\Helpers\Current_Post_Helper;
+use Yoast\WP\Free\Presenters\Head_Presenter;
+use Yoast\WP\Free\Repositories\Indexable_Repository;
+use Yoast\WP\Free\WordPress\Integration;
+use Yoast\WP\Free\Wrappers\WP_Query_Wrapper;
+use Yoast\WP\Free\Presenters\Post_Type\Head_Presenter as Post_Type_Head_Presenter;
+use YoastSEO_Vendor\Symfony\Component\DependencyInjection\ContainerInterface;
+
+class Front_End_Integration implements Integration {
+
+	/**
+	 * @inheritDoc
+	 */
+	public static function get_conditionals() {
+		return [ Front_End_Conditional::class, Indexables_Feature_Flag_Conditional::class ];
+	}
+
+	/**
+	 * @var Current_Post_Helper
+	 */
+	protected $current_post_helper;
+
+	/**
+	 * @var Indexable_Repository
+	 */
+	protected $indexable_repository;
+
+	/**
+	 * @var WP_Query_Wrapper
+	 */
+	protected $wp_query_wrapper;
+
+	/**
+	 * @var ContainerInterface
+	 */
+	protected $container;
+
+	/**
+	 * Front_End_Integration constructor.
+	 *
+	 * @param Indexable_Repository $indexable_repository
+	 * @param Current_Post_Helper  $current_post_helper
+	 * @param WP_Query_Wrapper     $wp_query_wrapper
+	 * @param Head_Presenter       $head_presenter
+	 */
+	public function __construct(
+		Indexable_Repository $indexable_repository,
+		Current_Post_Helper $current_post_helper,
+		WP_Query_Wrapper $wp_query_wrapper,
+		ContainerInterface $container
+	) {
+		$this->indexable_repository = $indexable_repository;
+		$this->current_post_helper = $current_post_helper;
+		$this->wp_query_wrapper = $wp_query_wrapper;
+		$this->container = $container;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function register_hooks() {
+		add_action( 'wp_head', [ $this, 'present_head' ], 1 );
+
+		remove_action( 'wp_head', 'rel_canonical' );
+		remove_action( 'wp_head', 'index_rel_link' );
+		remove_action( 'wp_head', 'start_post_rel_link' );
+		remove_action( 'wp_head', 'adjacent_posts_rel_link_wp_head' );
+		remove_action( 'wp_head', 'noindex', 1 );
+	}
+
+	/**
+	 * Presents the head in the front-end. Resets wp_query if it's not the main query.
+	 */
+	public function present_head() {
+		$wp_query = $this->wp_query_wrapper->get_query();
+		$old_wp_query = null;
+
+		if ( ! $wp_query->is_main_query() ) {
+			$old_wp_query = $wp_query;
+			\wp_reset_query();
+		}
+
+		$indexable = $this->indexable_repository->for_current_page();
+		$this->get_head_presenter()->present( $indexable );
+		/**
+		 * Action: 'wpseo_head' - Allow other plugins to output inside the Yoast SEO section of the head section.
+		 */
+		do_action( 'wpseo_head' );
+
+		if ( ! empty( $old_wp_query ) ) {
+			$this->wp_query_wrapper->set_query( $old_wp_query );
+		}
+	}
+
+	public function get_head_presenter() {
+		if ( $this->current_post_helper->is_simple_page() ) {
+			return $this->container->get( Post_Type_Head_Presenter::class );
+		}
+	}
+}

src/watchers/indexable-author-watcher.php → src/integrations/watchers/indexable-author-watcher.php

@@ -5,7 +5,7 @@
  * @package Yoast\YoastSEO\Watchers
  */
 
-namespace Yoast\WP\Free\Watchers;
+namespace Yoast\WP\Free\Integrations\Watchers;
 
 use Yoast\WP\Free\Conditionals\Indexables_Feature_Flag_Conditional;
 use Yoast\WP\Free\Builders\Indexable_Author_Builder;

src/watchers/indexable-post-watcher.php → src/integrations/watchers/indexable-post-watcher.php

@@ -5,7 +5,7 @@
  * @package Yoast\YoastSEO\Watchers
  */
 
-namespace Yoast\WP\Free\Watchers;
+namespace Yoast\WP\Free\Integrations\Watchers;
 
 use Yoast\WP\Free\Conditionals\Indexables_Feature_Flag_Conditional;
 use Yoast\WP\Free\Builders\Indexable_Post_Builder;

src/watchers/indexable-term-watcher.php → src/integrations/watchers/indexable-term-watcher.php

@@ -5,7 +5,7 @@
  * @package Yoast\YoastSEO\Watchers
  */
 
-namespace Yoast\WP\Free\Watchers;
+namespace Yoast\WP\Free\Integrations\Watchers;
 
 use Yoast\WP\Free\Conditionals\Indexables_Feature_Flag_Conditional;
 use Yoast\WP\Free\Builders\Indexable_Term_Builder;

src/watchers/primary-term-watcher.php → src/integrations/watchers/primary-term-watcher.php

@@ -5,7 +5,7 @@
  * @package Yoast\YoastSEO\Watchers
  */
 
-namespace Yoast\WP\Free\Watchers;
+namespace Yoast\WP\Free\Integrations\Watchers;
 
 use WPSEO_Meta;
 use Yoast\WP\Free\Conditionals\Indexables_Feature_Flag_Conditional;

src/loader.php

@@ -42,6 +42,7 @@ class Loader {
 	 */
 	public function __construct( ContainerInterface $container ) {
 		$this->container = $container;
+		add_filter( 'wpseo_get_class', [ $this->container, 'get' ] );
 	}
 
 	/**

src/loggers/logger.php

@@ -12,7 +12,7 @@
 use YoastSEO_Vendor\Psr\Log\NullLogger;
 
 /**
- * Creates an instance of a logger object.
+ * Our logger class.
  */
 class Logger implements LoggerInterface {
 	use LoggerTrait;

src/main.php

@@ -16,23 +16,71 @@
 	exit();
 }
 
-$development = \defined( 'YOAST_ENVIRONMENT' ) && \YOAST_ENVIRONMENT === 'development';
-if ( $development && \class_exists( '\Yoast\WP\Free\Dependency_Injection\Container_Compiler' ) ) {
-	// Exception here is unhandled as it will only occur in development.
-	Container_Compiler::compile( $development );
-}
+class Main {
+
+	/**
+	 * Initializes the plugin.
+	 */
+	public function initialize() {
+		$dependency_management = new Dependency_Management();
+		$dependency_management->initialize();
+		$this->load();
+	}
+
+	/**
+	 * Loads the plugin.
+	 *
+	 * @throws \Exception If loading fails and YOAST_ENVIRONMENT is development.
+	 */
+	public function load() {
+		try {
+			$container = $this->get_container();
+
+			if ( ! $container ) {
+				return;
+			}
+
+			$container->get( Loader::class )->load();
+		} catch ( \Exception $e ) {
+			if ( $this->is_development() ) {
+				throw $e;
+			}
+			// Don't crash the entire site, simply don't load.
+			// TODO: Add error notifications here.
+		}
+	}
+
+	/**
+	 * Loads the DI container.
+	 *
+	 * @return null|Cached_Container The DI container.
+	 *
+	 * @throws \Exception If something goes wrong generating the DI container.
+	 */
+	private function get_container() {
+		if ( $this->is_development() && \class_exists( '\Yoast\WP\Free\Dependency_Injection\Container_Compiler' ) ) {
+			// Exception here is unhandled as it will only occur in development.
+			Container_Compiler::compile( $this->is_development() );
+		}
 
-if ( \file_exists( __DIR__ . '/generated/container.php' ) ) {
-	require_once __DIR__ . '/generated/container.php';
-	$container = new Cached_Container();
-	try {
-		$container->get( Loader::class )->load();
-	} catch ( \Exception $e ) {
-		if ( $development ) {
-			throw $e;
+		if ( \file_exists( __DIR__ . '/generated/container.php' ) ) {
+			require_once __DIR__ . '/generated/container.php';
+			return new Cached_Container();
 		}
-		// Don't crash the entire site, simply don't load.
-		// TODO: Add error notifications here.
+
+		return null;
+	}
+
+	/**
+	 * Returns whether or not we're in an environment for Yoast development.
+	 *
+	 * @return bool Whether or not to load in development mode.
+	 */
+	private function is_development() {
+		return \defined( 'YOAST_ENVIRONMENT' ) && \YOAST_ENVIRONMENT === 'development';
 	}
 }
 
+$main = new Main();
+$main->initialize();
+