129 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
			
		
		
	
	
			129 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
<?php
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namespace Activitypub\Rest;
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use stdClass;
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use WP_Error;
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use WP_REST_Response;
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use Activitypub\Signature;
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use Activitypub\Model\Application_User;
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/**
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 * ActivityPub Server REST-Class
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 *
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 * @author Django Doucet
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 *
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 * @see https://www.w3.org/TR/activitypub/#security-verification
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 */
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class Server {
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	/**
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	 * Initialize the class, registering WordPress hooks
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	 */
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	public static function init() {
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		self::register_routes();
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		\add_filter( 'rest_request_before_callbacks', array( self::class, 'authorize_activitypub_requests' ), 10, 3 );
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	}
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	/**
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	 * Register routes
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	 */
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	public static function register_routes() {
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		\register_rest_route(
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			ACTIVITYPUB_REST_NAMESPACE,
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			'/application',
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			array(
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				array(
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					'methods'             => \WP_REST_Server::READABLE,
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					'callback'            => array( self::class, 'application_actor' ),
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					'permission_callback' => '__return_true',
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				),
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			)
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		);
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	}
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	/**
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	 * Render Application actor profile
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	 *
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	 * @return WP_REST_Response The JSON profile of the Application Actor.
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	 */
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	public static function application_actor() {
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		$user = new Application_User();
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		$json = $user->to_array();
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		$rest_response = new WP_REST_Response( $json, 200 );
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		$rest_response->header( 'Content-Type', 'application/activity+json; charset=' . get_option( 'blog_charset' ) );
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		return $rest_response;
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	}
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	/**
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	 * Callback function to authorize each api requests
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	 *
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	 * @see WP_REST_Request
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	 *
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	 * @param WP_REST_Response|WP_HTTP_Response|WP_Error|mixed $response Result to send to the client.
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	 *                                                                   Usually a WP_REST_Response or WP_Error.
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	 * @param array                                            $handler  Route handler used for the request.
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	 * @param WP_REST_Request                                  $request  Request used to generate the response.
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	 *
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	 * @return mixed|WP_Error The response, error, or modified response.
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	 */
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	public static function authorize_activitypub_requests( $response, $handler, $request ) {
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		if ( 'HEAD' === $request->get_method() ) {
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			return $response;
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		}
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		$route = $request->get_route();
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		// check if it is an activitypub request and exclude webfinger and nodeinfo endpoints
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		if (
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			! \str_starts_with( $route, '/' . ACTIVITYPUB_REST_NAMESPACE ) ||
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			\str_starts_with( $route, '/' . \trailingslashit( ACTIVITYPUB_REST_NAMESPACE ) . 'webfinger' ) ||
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			\str_starts_with( $route, '/' . \trailingslashit( ACTIVITYPUB_REST_NAMESPACE ) . 'nodeinfo' )
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		) {
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			return $response;
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		}
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		/**
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		 * Filter to defer signature verification
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		 *
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		 * Skip signature verification for debugging purposes or to reduce load for
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		 * certain Activity-Types, like "Delete".
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		 *
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		 * @param bool            $defer   Whether to defer signature verification.
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		 * @param WP_REST_Request $request The request used to generate the response.
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		 *
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		 * @return bool Whether to defer signature verification.
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		 */
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		$defer = \apply_filters( 'activitypub_defer_signature_verification', false, $request );
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		if ( $defer ) {
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			return $response;
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		}
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		// POST-Requets are always signed
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		if ( 'GET' !== $request->get_method() ) {
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			$verified_request = Signature::verify_http_signature( $request );
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			if ( \is_wp_error( $verified_request ) ) {
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				return new WP_Error(
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					'activitypub_signature_verification',
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					$verified_request->get_error_message(),
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					array( 'status' => 401 )
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				);
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			}
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		} elseif ( 'GET' === $request->get_method() && ACTIVITYPUB_AUTHORIZED_FETCH ) { // GET-Requests are only signed in secure mode
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			$verified_request = Signature::verify_http_signature( $request );
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			if ( \is_wp_error( $verified_request ) ) {
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				return new WP_Error(
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					'activitypub_signature_verification',
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					$verified_request->get_error_message(),
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					array( 'status' => 401 )
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				);
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			}
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		}
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		return $response;
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	}
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}
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