Place Ad Blocking Recovery Tags on the website

includes/Core/Tags/Guards/WP_Query_404_Guard.php

@@ -0,0 +1,34 @@
+<?php
+/**
+ * Class Google\Site_Kit\Core\Tags\Guards\WP_Query_404_Guard
+ *
+ * @package   Google\Site_Kit\Core\Tags\Guards
+ * @copyright 2023 Google LLC
+ * @license   https://www.apache.org/licenses/LICENSE-2.0 Apache License 2.0
+ * @link      https://sitekit.withgoogle.com
+ */
+
+namespace Google\Site_Kit\Core\Tags\Guards;
+
+use Google\Site_Kit\Core\Guards\Guard_Interface;
+
+/**
+ * Class for WP_Query 404 guard.
+ *
+ * @since n.e.x.t
+ * @access private
+ * @ignore
+ */
+class WP_Query_404_Guard implements Guard_Interface {
+	/**
+	 * Determines whether the guarded tag can be activated or not.
+	 *
+	 * @since n.e.x.t
+	 *
+	 * @return bool TRUE if guarded tag can be activated, otherwise FALSE or an error.
+	 */
+	public function can_activate() {
+		return ! is_404();
+	}
+
+}

includes/Modules/AdSense.php

@@ -55,6 +55,9 @@
 use Google\Site_Kit\Core\Storage\Encrypted_Options;
 use Google\Site_Kit\Core\Storage\Options;
 use Google\Site_Kit\Core\Storage\User_Options;
+use Google\Site_Kit\Core\Tags\Guards\WP_Query_404_Guard;
+use Google\Site_Kit\Modules\AdSense\Ad_Blocking_Recovery_Tag_Guard;
+use Google\Site_Kit\Modules\AdSense\Ad_Blocking_Recovery_Web_Tag;
 use WP_Error;
 use WP_REST_Response;
 
@@ -787,14 +790,30 @@ private function register_tag() {
 			$tag = new Web_Tag( $settings['clientID'], self::MODULE_SLUG );
 		}
 
-		if ( ! $tag->is_tag_blocked() ) {
-			$tag->use_guard( new Tag_Verify_Guard( $this->context->input() ) );
-			$tag->use_guard( new Tag_Guard( $module_settings ) );
-			$tag->use_guard( new Auto_Ad_Guard( $module_settings ) );
-			$tag->use_guard( new Tag_Environment_Type_Guard() );
+		if ( $tag->is_tag_blocked() ) {
+			return;
+		}
+
+		$tag->use_guard( new Tag_Verify_Guard( $this->context->input() ) );
+		$tag->use_guard( new WP_Query_404_Guard() );
+		$tag->use_guard( new Tag_Guard( $module_settings ) );
+		$tag->use_guard( new Auto_Ad_Guard( $module_settings ) );
+		$tag->use_guard( new Tag_Environment_Type_Guard() );
+
+		if ( $tag->can_register() ) {
+			$tag->register();
+		}
+
+		if ( Feature_Flags::enabled( 'adBlockerDetection' ) && ! $this->context->is_amp() ) {
+			$ad_blocking_recovery_web_tag = new Ad_Blocking_Recovery_Web_Tag( $this->ad_blocking_recovery_tag, $settings['useAdBlockerDetectionErrorSnippet'] );
+
+			$ad_blocking_recovery_web_tag->use_guard( new Tag_Verify_Guard( $this->context->input() ) );
+			$ad_blocking_recovery_web_tag->use_guard( new WP_Query_404_Guard() );
+			$ad_blocking_recovery_web_tag->use_guard( new Ad_Blocking_Recovery_Tag_Guard( $module_settings ) );
+			$ad_blocking_recovery_web_tag->use_guard( new Tag_Environment_Type_Guard() );
 
-			if ( $tag->can_register() ) {
-				$tag->register();
+			if ( $ad_blocking_recovery_web_tag->can_register() ) {
+				$ad_blocking_recovery_web_tag->register();
 			}
 		}
 	}

includes/Modules/AdSense/Ad_Blocking_Recovery_Tag_Guard.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * Class Google\Site_Kit\Modules\AdSense\Ad_Blocking_Recovery_Tag_Guard
+ *
+ * @package   Google\Site_Kit\Modules\AdSense
+ * @copyright 2023 Google LLC
+ * @license   https://www.apache.org/licenses/LICENSE-2.0 Apache License 2.0
+ * @link      https://sitekit.withgoogle.com
+ */
+
+namespace Google\Site_Kit\Modules\AdSense;
+
+use Google\Site_Kit\Core\Modules\Tags\Module_Tag_Guard;
+
+/**
+ * Class for the AdSense Ad Blocking Recovery tag guard.
+ *
+ * @since n.e.x.t
+ * @access private
+ * @ignore
+ */
+class Ad_Blocking_Recovery_Tag_Guard extends Module_Tag_Guard {
+
+	/**
+	 * Determines whether the guarded tag can be activated or not.
+	 *
+	 * @since n.e.x.t
+	 *
+	 * @return bool TRUE if guarded tag can be activated, otherwise FALSE or an error.
+	 */
+	public function can_activate() {
+		$settings = $this->settings->get();
+
+		return ! empty( $settings['adBlockingRecoverySetupStatus'] ) && $settings['useAdBlockerDetectionSnippet'];
+	}
+}

includes/Modules/AdSense/Ad_Blocking_Recovery_Web_Tag.php

@@ -0,0 +1,95 @@
+<?php
+/**
+ * Class Google\Site_Kit\Modules\AdSense\Ad_Blocking_Recovery_Web_Tag
+ *
+ * @package   Google\Site_Kit\Modules\AdSense
+ * @copyright 2023 Google LLC
+ * @license   https://www.apache.org/licenses/LICENSE-2.0 Apache License 2.0
+ * @link      https://sitekit.withgoogle.com
+ */
+
+namespace Google\Site_Kit\Modules\AdSense;
+
+use Google\Site_Kit\Core\Tags\Tag;
+use Google\Site_Kit\Core\Util\Method_Proxy_Trait;
+use Google\Site_Kit\Core\Tags\Tag_With_DNS_Prefetch_Trait;
+
+/**
+ * Class for Ad Blocking Recovery tag.
+ *
+ * @since n.e.x.t
+ * @access private
+ * @ignore
+ */
+class Ad_Blocking_Recovery_Web_Tag extends Tag {
+
+	use Method_Proxy_Trait;
+	use Tag_With_DNS_Prefetch_Trait;
+
+	/**
+	 * Ad_Blocking_Recovery_Tag instance.
+	 *
+	 * @since n.e.x.t
+	 * @var Ad_Blocking_Recovery_Tag
+	 */
+	protected $ad_blocking_recovery_tag;
+
+	/**
+	 * Use Error Protection Snippet.
+	 *
+	 * @since n.e.x.t
+	 * @var bool
+	 */
+	protected $use_error_protection_snippet;
+
+	/**
+	 * Constructor.
+	 *
+	 * @since n.e.x.t
+	 *
+	 * @param Ad_Blocking_Recovery_Tag $ad_blocking_recovery_tag Ad_Blocking_Recovery_Tag instance.
+	 * @param bool                     $use_error_protection_snippet Use Error Protection Snippet.
+	 */
+	public function __construct( Ad_Blocking_Recovery_Tag $ad_blocking_recovery_tag, $use_error_protection_snippet ) {
+		$this->ad_blocking_recovery_tag     = $ad_blocking_recovery_tag;
+		$this->use_error_protection_snippet = $use_error_protection_snippet;
+	}
+
+	/**
+	 * Registers tag hooks.
+	 *
+	 * @since n.e.x.t
+	 */
+	public function register() {
+		add_action( 'wp_head', $this->get_method_proxy_once( 'render' ) );
+
+		add_filter(
+			'wp_resource_hints',
+			$this->get_dns_prefetch_hints_callback( '//fundingchoicesmessages.google.com' ),
+			10,
+			2
+		);
+	}
+
+	/**
+	 * Outputs the AdSense script tag.
+	 *
+	 * @since n.e.x.t
+	 */
+	protected function render() {
+		$tags = $this->ad_blocking_recovery_tag->get();
+
+		if ( empty( $tags['tag'] ) || empty( $tags['error_protection_code'] ) ) {
+			return;
+		}
+
+		printf( "\n<!-- %s -->\n", esc_html__( 'Google AdSense Ad Blocking Recovery snippet added by Site Kit', 'google-site-kit' ) );
+		echo $tags['tag']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+		printf( "\n<!-- %s -->\n", esc_html__( 'End Google AdSense Ad Blocking Recovery snippet added by Site Kit', 'google-site-kit' ) );
+		if ( $this->use_error_protection_snippet ) {
+			printf( "\n<!-- %s -->\n", esc_html__( 'Google AdSense Ad Blocking Recovery Error Protection snippet added by Site Kit', 'google-site-kit' ) );
+			echo $tags['error_protection_code']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+			printf( "\n<!-- %s -->\n", esc_html__( 'End Google AdSense Ad Blocking Recovery Error Protection snippet added by Site Kit', 'google-site-kit' ) );
+		}
+	}
+}

includes/Modules/AdSense/Tag_Guard.php

@@ -26,15 +26,11 @@ class Tag_Guard extends Module_Tag_Guard {
 	 *
 	 * @since 1.24.0
 	 * @since 1.30.0 Update to return FALSE on 404 pages deliberately.
+	 * @since n.e.x.t Extract the check for 404 pages to dedicated Guard.
 	 *
 	 * @return bool|WP_Error TRUE if guarded tag can be activated, otherwise FALSE or an error.
 	 */
 	public function can_activate() {
-		// Do not allow AdSense tags on 404 pages.
-		if ( is_404() ) {
-			return false;
-		}
-
 		$settings = $this->settings->get();
 
 		// For web stories, the tag must only be rendered if a story-specific ad unit is provided.

tests/phpunit/integration/Core/Tags/Guards/WP_Query_404_GuardTest.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * WP_Query_404_GuardTest
+ *
+ * @package   Google\Site_Kit\Tests\Core\Tags\Guards
+ * @copyright 2023 Google LLC
+ * @license   https://www.apache.org/licenses/LICENSE-2.0 Apache License 2.0
+ * @link      https://sitekit.withgoogle.com
+ */
+
+namespace Google\Site_Kit\Tests\Core\Tags\Guards;
+
+use Google\Site_Kit\Core\Tags\Guards\WP_Query_404_Guard;
+use Google\Site_Kit\Tests\TestCase;
+
+class WP_Query_404_GuardTest extends TestCase {
+
+	public function test_can_activate() {
+		$guard = new WP_Query_404_Guard();
+
+		$this->go_to( '/' );
+
+		$this->assertQueryTrue( 'is_home', 'is_front_page' );
+		$this->assertTrue( $guard->can_activate(), 'Should return TRUE when the current page exists (is_home).' );
+	}
+
+	public function test_cant_activate_on_404() {
+		$guard = new WP_Query_404_Guard();
+
+		$this->go_to( '/?p=123456789' );
+
+		$this->assertQueryTrue( 'is_404' );
+		$this->assertFalse( $guard->can_activate(), 'Should return FALSE when the current page doesnt exist (is_404).' );
+	}
+
+}

tests/phpunit/integration/Modules/AdSense/Ad_Blocking_Recovery_Tag_GuardTest.php

@@ -0,0 +1,72 @@
+<?php
+/**
+ * Class Google\Site_Kit\Tests\Modules\AdSense\Ad_Blocking_Recovery_Tag_GuardTest
+ *
+ * @package   Google\Site_Kit\Tests\Modules\AdSense
+ * @copyright 2023 Google LLC
+ * @license   https://www.apache.org/licenses/LICENSE-2.0 Apache License 2.0
+ * @link      https://sitekit.withgoogle.com
+ */
+
+namespace Google\Site_Kit\Tests\Modules\AdSense;
+
+use Google\Site_Kit\Context;
+use Google\Site_Kit\Core\Storage\Options;
+use Google\Site_Kit\Modules\AdSense\Settings;
+use Google\Site_Kit\Modules\AdSense\Ad_Blocking_Recovery_Tag_Guard;
+use Google\Site_Kit\Tests\TestCase;
+
+/**
+ * @group Modules
+ * @group AdSense
+ */
+class Ad_Blocking_Recovery_Tag_GuardTest extends TestCase {
+
+	/**
+	 * Settings object.
+	 *
+	 * @var Settings
+	 */
+	private $settings;
+
+	/**
+	 * Ad_Blocking_Recovery_Tag_Guard object.
+	 *
+	 * @var Ad_Blocking_Recovery_Tag_Guard
+	 */
+	private $guard;
+
+	public function set_up() {
+		parent::set_up();
+
+		update_option(
+			Settings::OPTION,
+			array(
+				'adBlockingRecoverySetupStatus' => 'tag-placed',
+				'useAdBlockerDetectionSnippet'  => true,
+			)
+		);
+
+		$this->settings = new Settings( new Options( new Context( GOOGLESITEKIT_PLUGIN_MAIN_FILE ) ) );
+		$this->guard    = new Ad_Blocking_Recovery_Tag_Guard( $this->settings );
+	}
+
+	public function test_can_activate() {
+		$this->assertTrue( $this->guard->can_activate() );
+	}
+
+	/**
+	 * @dataProvider data_can_not_activate
+	 */
+	public function test_can_not_activate( $settings ) {
+		$this->settings->merge( $settings );
+		$this->assertFalse( $this->guard->can_activate() );
+	}
+
+	public function data_can_not_activate() {
+		return array(
+			'when adBlockingRecoverySetupStatus is empty' => array( array( 'adBlockingRecoverySetupStatus' => '' ) ),
+			'when useAdBlockerDetectionSnippet is falsy'  => array( array( 'useAdBlockerDetectionSnippet' => false ) ),
+		);
+	}
+}