Make sure that we cache only valid posts/pages urls

inc/Engine/Cache/PostSubscriber.php

@@ -0,0 +1,74 @@
+<?php
+namespace WP_Rocket\Engine\Cache;
+
+use WP_Rocket\Event_Management\Subscriber_Interface;
+
+/**
+ * Subscriber for the post/page frontend pages.
+ */
+class PostSubscriber implements Subscriber_Interface {
+	/**
+	 * {@inheritdoc}
+	 */
+	public static function get_subscribed_events() {
+		return [
+			'do_rocket_generate_caching_files' => 'disable_cache_on_not_valid_pages',
+			'rocket_buffer'                    => [ 'stop_optimizations_for_not_valid_pages', 1 ],
+		];
+	}
+
+	/**
+	 * Disable caching invalid page urls.
+	 *
+	 * @param bool $can_cache Filter callback passed value.
+	 * @return bool
+	 */
+	public function disable_cache_on_not_valid_pages( $can_cache ) {
+		if ( $this->is_not_valid_page() ) {
+			return false;
+		}
+
+		return $can_cache;
+	}
+
+	/**
+	 * Stop optimizing those invalid pages by returning empty html string,
+	 * So it fall back to the normal page's HTML.
+	 *
+	 * @param string $html Page's buffer HTML.
+	 * @return string
+	 */
+	public function stop_optimizations_for_not_valid_pages( $html ) {
+		return $this->is_not_valid_page() ? '' : $html;
+	}
+
+	/**
+	 * Check if we are on the post frontend page, but it's not valid url query.
+	 *
+	 * @return bool (True when not valid post url, False if it's a valid one)
+	 */
+	private function is_not_valid_page() {
+		if ( ! is_singular() ) {
+			return false;
+		}
+
+		$post_id = get_queried_object_id();
+		if ( empty( $post_id ) ) {
+			return false;
+		}
+
+		global $wp;
+
+		$post_link = get_permalink( $post_id );
+		if ( ! $post_link ) {
+			return false;
+		}
+
+		$current_link = home_url( add_query_arg( [], $wp->request ?? '' ) );
+		if ( is_paged() ) {
+			$post_link = trailingslashit( $post_link ) . 'page/' . get_query_var( 'paged' );
+		}
+
+		return urldecode( untrailingslashit( $post_link ) ) !== urldecode( untrailingslashit( $current_link ) );
+	}
+}

inc/Engine/Cache/ServiceProvider.php

@@ -28,6 +28,7 @@ class ServiceProvider extends AbstractServiceProvider {
 		'preload_caches_query',
 		'cache_config',
 		'taxonomy_subscriber',
+		'post_subscriber',
 	];
 
 	/**
@@ -77,5 +78,6 @@ public function register(): void {
 			->addArgument( $this->getContainer()->get( 'options' ) )
 			->addArgument( $this->getContainer()->get( 'options_api' ) );
 		$this->getContainer()->addShared( 'taxonomy_subscriber', TaxonomySubscriber::class );
+		$this->getContainer()->addShared( 'post_subscriber', PostSubscriber::class );
 	}
 }

inc/Engine/Common/PerformanceHints/Frontend/Subscriber.php

@@ -54,6 +54,10 @@ public static function get_subscribed_events(): array {
 	 * @return string
 	 */
 	public function maybe_apply_optimizations( $html ): string {
+		if ( empty( $html ) ) {
+			return $html;
+		}
+
 		if ( ! isset( $_GET['wpr_imagedimensions'] ) && isset( $_GET['wpr_lazyrendercontent'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
 			return $html;
 		}

inc/Plugin.php

@@ -408,6 +408,7 @@ private function init_common_subscribers() {
 			'media_fonts_frontend_subscriber',
 			'media_fonts_admin_subscriber',
 			'media_fonts_clean_subscriber',
+			'post_subscriber',
 		];
 
 		$host_type = HostResolver::get_host_service();

tests/Fixtures/inc/Engine/Cache/PostSubscriber/disableCacheOnNotValidPages.php

@@ -0,0 +1,68 @@
+<?php
+
+return [
+	'test_data' => [
+		'testIsNotInPostPage' => [
+			'config' => [
+				'is_singular' => false,
+			],
+			'can_cache' => true,
+		],
+		'testValidPostPage' => [
+			'config' => [
+				'is_singular' => true,
+				'current_post_id' => 1,
+				'current_post_link' => 'http://example.com/test1',
+				'current_page_url' => 'http://example.com/test1',
+			],
+			'can_cache' => true,
+		],
+		'testValidPostPageWithPagination' => [
+			'config' => [
+				'is_singular' => true,
+				'current_post_id' => 1,
+				'current_post_link' => 'http://example.com/test1',
+				'current_page_url' => 'http://example.com/test1/page/2',
+				'page' => 2,
+			],
+			'can_cache' => true,
+		],
+		'testEmptyPostId' => [
+			'config' => [
+				'is_singular' => true,
+				'current_post_id' => 0,
+				'current_post_link' => '',
+				'current_post_url' => 'http://example.com/test1',
+			],
+			'can_cache' => true,
+		],
+		'testNotValidPostPage' => [
+			'config' => [
+				'is_singular' => true,
+				'current_post_id' => 1,
+				'current_post_link' => 'http://example.com/test1',
+				'current_post_url' => 'http://example.com/additional-query/test1',
+			],
+			'can_cache' => false,
+		],
+		'testNotValidPostPageWithPagination' => [
+			'config' => [
+				'is_singular' => true,
+				'current_post_id' => 1,
+				'current_post_link' => 'http://example.com/test1',
+				'current_page_url' => 'http://example.com/additional-query/test1/page/2',
+				'page' => 2,
+			],
+			'can_cache' => false,
+		],
+		'testValidPostPageWithNonLatinCharactersInUrl' => [
+			'config' => [
+				'is_singular' => true,
+				'current_post_id' => 1,
+				'current_post_link' => 'http://example.com/%D0%BF%D1%80%D0%BE%D0%B4%D1%83%D0%BA%D1%82%D0%BE%D0%B2%D0%B0-%D0%BA%D0%B0%D1%82%D0%B5%D0%B3%D0%BE%D1%80%D0%B8%D1%8F/',
+				'current_page_url' => 'http://example.com/продуктова-категория/',
+			],
+			'can_cache' => true,
+		],
+	],
+];

tests/Unit/inc/Engine/Cache/PostSubscriber/disableCacheOnNotValidPages.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace WP_Rocket\Tests\Unit\inc\Engine\Cache\PostSubscriber;
+
+use Brain\Monkey\Functions;
+use WP_Rocket\Engine\Cache\PostSubscriber;
+use WP_Rocket\Tests\Unit\TestCase;
+
+/**
+ * Test class covering PostSubscriber::disable_cache_on_not_valid_pages
+ * @covers \WP_Rocket\Engine\Cache\PostSubscriber::disable_cache_on_not_valid_pages
+ *
+ * @uses PostSubscriber::is_not_valid_page
+ *
+ * @group Cache
+ */
+class Test_DisableCacheOnNotValidPages extends TestCase {
+	private $subscriber;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->subscriber = new PostSubscriber();
+	}
+
+
+	/**
+	 * @dataProvider configTestData
+	 */
+	public function testShouldReturnExpected( $config, $can_cache ) {
+		Functions\expect( 'is_singular' )->once()->andReturn( ! empty( $config['is_singular'] ) );
+		Functions\when( 'get_queried_object_id' )->justReturn( $config['current_post_id'] ?? 0 );
+
+		Functions\when( 'get_permalink' )->justReturn( $config['current_post_link'] ?? '' );
+		Functions\when( 'add_query_arg' )->justReturn( '' );
+		Functions\when( 'home_url' )->justReturn( $config['current_page_url'] ?? '' );
+		Functions\when( 'is_paged' )->justReturn( ! empty( $config['page'] ) );
+		Functions\when( 'get_query_var' )->justReturn( $config['page'] ?? 0 );
+
+		$this->assertSame( $can_cache, $this->subscriber->disable_cache_on_not_valid_pages( true ) );
+	}
+}