Integration: Add support for the LightSpeed Cache plugin

.github/changelog/1683-from-description

@@ -0,0 +1,4 @@
+Significance: minor
+Type: added
+
+Add LiteSpeed Cache integration to prevent ActivityPub JSON responses from being cached incorrectly. Includes automatic .htaccess rules and Site Health check to ensure proper configuration.

includes/functions.php

@@ -1828,3 +1828,23 @@ function get_url_authority( $url ) {
 
 	return $parsed['scheme'] . '://' . $parsed['host'];
 }
+
+/**
+ * Check if a plugin is active, loading plugin.php if necessary.
+ *
+ * This is a wrapper around the core is_plugin_active() function that ensures
+ * the function is available by loading wp-admin/includes/plugin.php if needed.
+ * This is useful when checking plugin status outside of the admin context.
+ *
+ * @param string $plugin Plugin basename (e.g., 'plugin-folder/plugin-file.php').
+ *
+ * @return bool True if the plugin is active, false otherwise.
+ */
+function is_plugin_active( $plugin ) {
+	// Include plugin.php if not already loaded (needed for core is_plugin_active).
+	if ( ! \function_exists( 'is_plugin_active' ) ) {
+		require_once ABSPATH . 'wp-admin/includes/plugin.php';
+	}
+
+	return \is_plugin_active( $plugin );
+}

integration/class-litespeed-cache.php

@@ -0,0 +1,227 @@
+<?php
+/**
+ * LiteSpeed Cache integration file.
+ *
+ * @package Activitypub
+ */
+
+namespace Activitypub\Integration;
+
+use function Activitypub\is_plugin_active;
+
+/**
+ * LiteSpeed Cache integration.
+ *
+ * @see https://wordpress.org/support/topic/avoiding-caching-activitypub-content/
+ */
+class Litespeed_Cache {
+
+	/**
+	 * The rules to add to the htaccess file.
+	 *
+	 * @var string
+	 */
+	public static $rules = '<IfModule LiteSpeed>
+RewriteEngine On
+RewriteCond %{HTTP:Accept} application
+RewriteRule ^ - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+isjson]
+</IfModule>';
+
+	/**
+	 * The option name to store the htaccess rules.
+	 *
+	 * @var string
+	 */
+	public static $option_name = 'activitypub_litespeed_cache_setup';
+
+	/**
+	 * The marker to identify the rules in the htaccess file.
+	 *
+	 * @var string
+	 */
+	public static $marker = 'ActivityPub LiteSpeed Cache';
+
+	/**
+	 * The LiteSpeed Cache plugin slug.
+	 *
+	 * @var string
+	 */
+	public static $plugin_slug = 'litespeed-cache/litespeed-cache.php';
+
+	/**
+	 * Initialize the integration.
+	 */
+	public static function init() {
+		// Add rules if LiteSpeed Cache is active and rules aren't set.
+		if ( is_plugin_active( self::$plugin_slug ) ) {
+			if ( ! \get_option( self::$option_name ) ) {
+				self::add_htaccess_rules();
+			}
+
+			\add_filter( 'site_status_tests', array( self::class, 'add_site_health_test' ) );
+
+			// Remove rules if LiteSpeed Cache is not active but rules were previously set.
+		} elseif ( \get_option( self::$option_name ) ) {
+			self::remove_htaccess_rules();
+		}
+
+		// Clean up when LiteSpeed Cache plugin is deleted.
+		\add_action( 'deleted_plugin', array( self::class, 'on_plugin_deleted' ) );
+	}
+
+	/**
+	 * Clean up htaccess rules when LiteSpeed Cache plugin is deleted.
+	 *
+	 * @param string $plugin_file Path to the plugin file relative to the plugins directory.
+	 */
+	public static function on_plugin_deleted( $plugin_file ) {
+		if ( self::$plugin_slug === $plugin_file && \get_option( self::$option_name ) ) {
+			self::remove_htaccess_rules();
+		}
+	}
+
+	/**
+	 * Add the LiteSpeed Cache htaccess rules.
+	 */
+	public static function add_htaccess_rules() {
+		$added_rules = self::append_with_markers( self::$marker, self::$rules );
+
+		if ( $added_rules ) {
+			\update_option( self::$option_name, '1' );
+		} else {
+			\update_option( self::$option_name, '0' );
+		}
+	}
+
+	/**
+	 * Remove the LiteSpeed Cache htaccess rules.
+	 */
+	public static function remove_htaccess_rules() {
+		self::append_with_markers( self::$marker, '' );
+
+		\delete_option( self::$option_name );
+	}
+
+	/**
+	 * Add the LiteSpeed Cache config test to site health.
+	 *
+	 * @param array $tests The site health tests.
+	 *
+	 * @return array The site health tests with the LiteSpeed Cache config test.
+	 */
+	public static function add_site_health_test( $tests ) {
+		$tests['direct']['activitypub_test_litespeed_cache_integration'] = array(
+			'label' => \__( 'LiteSpeed Cache Test', 'activitypub' ),
+			'test'  => array( self::class, 'test_litespeed_cache_integration' ),
+		);
+
+		return $tests;
+	}
+
+	/**
+	 * Test the LiteSpeed Cache integration.
+	 *
+	 * @return array The test results.
+	 */
+	public static function test_litespeed_cache_integration() {
+		$result = array(
+			'label'       => \__( 'Compatibility with LiteSpeed Cache', 'activitypub' ),
+			'status'      => 'good',
+			'badge'       => array(
+				'label' => \__( 'ActivityPub', 'activitypub' ),
+				'color' => 'green',
+			),
+			'description' => \sprintf(
+				'<p>%s</p>',
+				\__( 'LiteSpeed Cache is well configured to work with ActivityPub.', 'activitypub' )
+			),
+			'actions'     => '',
+			'test'        => 'test_litespeed_cache_integration',
+		);
+
+		if ( ! \get_option( self::$option_name ) ) {
+			$result['status']         = 'critical';
+			$result['label']          = \__( 'LiteSpeed Cache might not be properly configured.', 'activitypub' );
+			$result['badge']['color'] = 'red';
+			$result['description']    = \sprintf(
+				'<p>%s</p>',
+				\__( 'LiteSpeed Cache isn&#8217;t currently set up to work with ActivityPub. While this isn&#8217;t a major problem, it&#8217;s a good idea to enable support. Without it, some technical files (like JSON) might accidentally show up in your website&#8217;s cache and be visible to visitors.', 'activitypub' )
+			);
+			$result['actions']        = \sprintf(
+				'<p>%s</p><pre>%s</pre>',
+				\__( 'To enable the ActivityPub integration with LiteSpeed Cache, add the following rules to your <code>.htaccess</code> file:', 'activitypub' ),
+				\esc_html( self::$rules )
+			);
+		}
+
+		return $result;
+	}
+
+	/**
+	 * Prepend rules to the top of a file with markers.
+	 *
+	 * @param string $marker The marker to identify the rules in the file.
+	 * @param string $rules  The rules to prepend.
+	 *
+	 * @return bool True on success, false on failure.
+	 */
+	private static function append_with_markers( $marker, $rules ) {
+		$htaccess_file = self::get_htaccess_file_path();
+
+		if ( ! \wp_is_writable( $htaccess_file ) ) {
+			return false;
+		}
+
+		// Ensure get_home_path() is declared.
+		require_once ABSPATH . 'wp-admin/includes/file.php';
+
+		global $wp_filesystem;
+		\WP_Filesystem();
+
+		$htaccess = $wp_filesystem->get_contents( $htaccess_file );
+
+		// If marker exists, remove the old block first.
+		if ( strpos( $htaccess, $marker ) !== false ) {
+			// Remove existing marker block.
+			$pattern  = '/# BEGIN ' . preg_quote( $marker, '/' ) . '.*?# END ' . preg_quote( $marker, '/' ) . '\r?\n?/s';
+			$htaccess = preg_replace( $pattern, '', $htaccess );
+			$htaccess = trim( $htaccess );
+		}
+
+		// If rules are empty, just return (for removal case).
+		if ( empty( $rules ) ) {
+			return $wp_filesystem->put_contents( $htaccess_file, $htaccess, FS_CHMOD_FILE );
+		}
+
+		// Prepend new rules to the top of the file.
+		$start_marker = "# BEGIN {$marker}";
+		$end_marker   = "# END {$marker}";
+
+		$rules    = $start_marker . PHP_EOL . $rules . PHP_EOL . $end_marker;
+		$htaccess = $rules . PHP_EOL . PHP_EOL . $htaccess;
+
+		return $wp_filesystem->put_contents( $htaccess_file, $htaccess, FS_CHMOD_FILE );
+	}
+
+	/**
+	 * Get the htaccess file.
+	 *
+	 * @return string|false The htaccess file or false.
+	 */
+	private static function get_htaccess_file_path() {
+		$htaccess_file = false;
+
+		// phpcs:ignore WordPress.PHP.NoSilencedErrors
+		if ( @file_exists( \get_home_path() . '.htaccess' ) ) {
+			/** The htaccess file resides in ABSPATH */
+			$htaccess_file = \get_home_path() . '.htaccess';
+		}
+
+		/**
+		 * Filter the htaccess file path.
+		 *
+		 * @param string|false $htaccess_file The htaccess file path.
+		 */
+		return \apply_filters( 'activitypub_litespeed_cache_htaccess_file', $htaccess_file );
+	}
+}

integration/class-surge.php

@@ -7,6 +7,8 @@
 
 namespace Activitypub\Integration;
 
+use function Activitypub\is_plugin_active;
+
 /**
  * Surge Cache integration.
  *
@@ -38,7 +40,7 @@ public static function init() {
 	 */
 	public static function add_cache_config() {
 		// Check if surge is installed and active.
-		if ( ! \is_plugin_active( 'surge/surge.php' ) ) {
+		if ( ! is_plugin_active( 'surge/surge.php' ) ) {
 			return;
 		}
 
@@ -139,7 +141,7 @@ public static function get_config_file_path() {
 	 * @return array The site health tests with the Surge cache config test.
 	 */
 	public static function maybe_add_site_health( $tests ) {
-		if ( ! \is_plugin_active( 'surge/surge.php' ) ) {
+		if ( ! is_plugin_active( 'surge/surge.php' ) ) {
 			return $tests;
 		}
 

integration/load.php

@@ -146,13 +146,27 @@ function ( $transformer, $data, $object_class ) {
 	 * @see https://wordpress.org/plugins/surge/
 	 */
 	Surge::init();
+
+	/**
+	 * Load the LiteSpeed Cache integration.
+	 *
+	 * The check for whether LiteSpeed Cache is loaded and initialized happens inside Litespeed_Cache::init().
+	 *
+	 * @see https://wordpress.org/plugins/litespeed-cache/
+	 */
+	Litespeed_Cache::init();
 }
 \add_action( 'plugins_loaded', __NAMESPACE__ . '\plugin_init' );
 
 // Register activation and deactivation hooks for Surge integration.
 \register_activation_hook( ACTIVITYPUB_PLUGIN_FILE, array( __NAMESPACE__ . '\Surge', 'add_cache_config' ) );
 \register_deactivation_hook( ACTIVITYPUB_PLUGIN_FILE, array( __NAMESPACE__ . '\Surge', 'remove_cache_config' ) );
 
+// Register activation and deactivation hooks for LiteSpeed Cache integration.
+\register_activation_hook( ACTIVITYPUB_PLUGIN_FILE, array( __NAMESPACE__ . '\LiteSpeed_Cache', 'add_htaccess_rules' ) );
+\register_deactivation_hook( ACTIVITYPUB_PLUGIN_FILE, array( __NAMESPACE__ . '\LiteSpeed_Cache', 'remove_htaccess_rules' ) );
+
+
 /**
  * Register the Stream Connector for ActivityPub.
  *