Delete chat messages

appinfo/routes.php

@@ -153,6 +153,16 @@
 				'token' => '^[a-z0-9]{4,30}$',
 			],
 		],
+		[
+			'name' => 'Chat#deleteMessage',
+			'url' => '/api/{apiVersion}/chat/{token}/{messageId}',
+			'verb' => 'DELETE',
+			'requirements' => [
+				'apiVersion' => 'v1',
+				'token' => '^[a-z0-9]{4,30}$',
+				'messageId' => '^[0-9]+$',
+			],
+		],
 		[
 			'name' => 'Chat#setReadMarker',
 			'url' => '/api/{apiVersion}/chat/{token}/read',

docs/capabilities.md

@@ -64,3 +64,6 @@ title: Capabilities
 * `room-description` - A description can be get and set for conversations.
 * `config => chat => read-privacy` - See `chat-read-status`
 * `config => previews => max-gif-size` - Maximum size in bytes below which a GIF can be embedded directly in the page at render time. Bigger files will be rendered statically using the preview endpoint instead. Can be set with `occ config:app:set spreed max-gif-size --value=X` where X is the new value in bytes. Defaults to 3 MB.
+
+## 12.0
+* `delete-messages` - Allows to delete chat messages up to 6 hours for your own messages or when being a moderator. On deleting the message text will be replaced and a follow up system message will make sure clients and users update it in their cache and storage.

docs/chat.md

@@ -44,7 +44,7 @@ Base endpoint is: `/ocs/v2.php/apps/spreed/api/v1`
         `actorDisplayName` | string | Display name of the message author
         `timestamp` | int | Timestamp in seconds and UTC time zone
         `systemMessage` | string | empty for normal chat message or the type of the system message (untranslated)
-        `messageType` | string | Currently known types are `comment`, `system` and `command`
+        `messageType` | string | Currently known types are `comment`, `comment_deleted`, `system` and `command`
         `isReplyable` | bool | True if the user can post a reply to this message (only available with `chat-replies` capability)
         `referenceId` | string | A reference string that was given while posting the message to be able to identify a sent message again (only available with `chat-reference-id` capability)
         `message` | string | Message string with placeholders (see [Rich Object String](https://github.com/nextcloud/server/issues/1706))
@@ -96,6 +96,35 @@ Base endpoint is: `/ocs/v2.php/apps/spreed/api/v1`
     - Data:
         The full message array of the new message, as defined in [Receive chat messages of a conversation](#receive-chat-messages-of-a-conversation)
 
+
+## Deleting a chat message
+
+* Method: `DELETE`
+* Endpoint: `/chat/{token}/{messageId}`
+
+* Response:
+    - Status code:
+        + `200 OK` - When deleting was successful
+        + `202 Accepted` - When deleting was successful but Matterbridge is enabled so the message was leaked to other services
+        + `400 Bad Request` The message is already older than 6 hours
+        + `403 Forbidden` When the message is not from the current user and the user not a moderator
+        + `403 Forbidden` When the conversation is read-only
+        + `404 Not Found` When the conversation or chat message could not be found for the participant
+        + `405 Method Not Allowed` When the message is not a normal chat message
+        + `412 Precondition Failed` When the lobby is active and the user is not a moderator
+
+    - Header:
+
+        field | type | Description
+        ------|------|------------
+        `X-Chat-Last-Common-Read` | int | ID of the last message read by every user that has read privacy set to public. When the user themself has it set to private the value the header is not set (only available with `chat-read-status` capability)
+
+    - Data:
+        The full message array of the new system message "You deleted a message", as defined in [Receive chat messages of a conversation](#receive-chat-messages-of-a-conversation)
+        The parent message is the object of the deleted message with the replaced text "Message deleted by you".
+        This message should not be displayed to the user but instead be used to remove the original message from any cache/storage of the device.
+
+
 ## Mark chat as read
 
 * Method: `POST`
@@ -119,7 +148,6 @@ Base endpoint is: `/ocs/v2.php/apps/spreed/api/v1`
         `X-Chat-Last-Common-Read` | int | ID of the last message read by every user that has read privacy set to public. When the user themself has it set to private the value the header is not set (only available with `chat-read-status` capability)
 
 
-
 ## Get mention autocomplete suggestions
 
 * Method: `GET`
@@ -177,3 +205,4 @@ Base endpoint is: `/ocs/v2.php/apps/spreed/api/v1`
 * `moderator_demoted` - {actor} demoted {user} from moderator
 * `guest_moderator_promoted` - {actor} promoted {user} to moderator
 * `guest_moderator_demoted` - {actor} demoted {user} from moderator
+* `message_deleted` - Message deleted by {actor} (Should not be shown to the user)

lib/Capabilities.php

@@ -68,6 +68,7 @@ public function getCapabilities(): array {
 				'last-room-activity',
 				'no-ping',
 				'system-messages',
+				'delete-messages',
 				'mention-flag',
 				'in-call-flags',
 				'notification-levels',

lib/Chat/ChatManager.php

@@ -106,15 +106,28 @@ public function __construct(CommentsManager $commentsManager,
 	 * @param \DateTime $creationDateTime
 	 * @param bool $sendNotifications
 	 * @param string|null $referenceId
+	 * @param int|null $parentId
 	 * @return IComment
 	 */
-	public function addSystemMessage(Room $chat, string $actorType, string $actorId, string $message, \DateTime $creationDateTime, bool $sendNotifications, ?string $referenceId = null): IComment {
+	public function addSystemMessage(
+		Room $chat,
+		string $actorType,
+		string $actorId,
+		string $message,
+		\DateTime $creationDateTime,
+		bool $sendNotifications,
+		?string $referenceId = null,
+		?int $parentId = null
+	): IComment {
 		$comment = $this->commentsManager->create($actorType, $actorId, 'chat', (string) $chat->getId());
 		$comment->setMessage($message, self::MAX_CHAT_LENGTH);
 		$comment->setCreationDateTime($creationDateTime);
 		if ($referenceId !== null) {
 			$comment->setReferenceId($referenceId);
 		}
+		if ($parentId !== null) {
+			$comment->setParentId((string) $parentId);
+		}
 		$comment->setVerb('system');
 
 		$event = new ChatEvent($chat, $comment);
@@ -231,6 +244,30 @@ public function sendMessage(Room $chat, Participant $participant, string $actorT
 		return $comment;
 	}
 
+	public function deleteMessage(Room $chat, int $messageId, string $actorType, string $actorId, \DateTime $deletionTime): IComment {
+		$comment = $this->getComment($chat, (string) $messageId);
+		$comment->setMessage(
+			json_encode([
+				'deleted_by_type' => $actorType,
+				'deleted_by_id' => $actorId,
+				'deleted_on' => $deletionTime->getTimestamp(),
+			])
+		);
+		$comment->setVerb('comment_deleted');
+		$this->commentsManager->save($comment);
+
+		return $this->addSystemMessage(
+			$chat,
+			$actorType,
+			$actorId,
+			json_encode(['message' => 'message_deleted', 'parameters' => ['message' => $messageId]]),
+			$this->timeFactory->getDateTime(),
+			false,
+			null,
+			$messageId
+		);
+	}
+
 	/**
 	 * @param Room $chat
 	 * @param string $parentId
@@ -247,6 +284,22 @@ public function getParentComment(Room $chat, string $parentId): IComment {
 		return $comment;
 	}
 
+	/**
+	 * @param Room $chat
+	 * @param string $messageId
+	 * @return IComment
+	 * @throws NotFoundException
+	 */
+	public function getComment(Room $chat, string $messageId): IComment {
+		$comment = $this->commentsManager->get($messageId);
+
+		if ($comment->getObjectType() !== 'chat' || $comment->getObjectId() !== (string) $chat->getId()) {
+			throw new NotFoundException('Message not found in the right context');
+		}
+
+		return $comment;
+	}
+
 	public function getLastReadMessageFromLegacy(Room $chat, IUser $user): int {
 		$marker = $this->commentsManager->getReadMark('chat', $chat->getId(), $user);
 		if ($marker === null) {

lib/Chat/Parser/Listener.php

@@ -96,5 +96,25 @@ public static function register(IEventDispatcher $dispatcher): void {
 				$event->stopPropagation();
 			}
 		});
+
+		$dispatcher->addListener(MessageParser::EVENT_MESSAGE_PARSE, static function (ChatMessageEvent $event) {
+			$chatMessage = $event->getMessage();
+
+			if ($chatMessage->getMessageType() !== 'comment_deleted') {
+				return;
+			}
+
+			/** @var SystemMessage $parser */
+			$parser = \OC::$server->query(SystemMessage::class);
+
+			try {
+				$parser->parseDeletedMessage($chatMessage);
+				$event->stopPropagation();
+			} catch (\OutOfBoundsException $e) {
+				// Unknown message, ignore
+			} catch (\RuntimeException $e) {
+				$event->stopPropagation();
+			}
+		}, 9999);// First things first
 	}
 }

lib/Chat/Parser/SystemMessage.php

@@ -89,7 +89,7 @@ public function parseMessage(Message $chatMessage): void {
 
 		$message = $data['message'];
 		$parameters = $data['parameters'];
-		$parsedParameters = ['actor' => $this->getActor($comment)];
+		$parsedParameters = ['actor' => $this->getActorFromComment($comment)];
 
 		$participant = $chatMessage->getParticipant();
 		if (!$participant->isGuest()) {
@@ -354,6 +354,57 @@ public function parseMessage(Message $chatMessage): void {
 			if ($currentUserIsActor) {
 				$parsedMessage = $this->l->t('You stopped Matterbridge.');
 			}
+		} elseif ($message === 'message_deleted') {
+			$parsedMessage = $this->l->t('{actor} deleted a message');
+			if ($currentUserIsActor) {
+				$parsedMessage = $this->l->t('You deleted a message');
+			}
+		} else {
+			throw new \OutOfBoundsException('Unknown subject');
+		}
+
+		$chatMessage->setMessage($parsedMessage, $parsedParameters, $message);
+	}
+
+	/**
+	 * @param Message $chatMessage
+	 * @throws \OutOfBoundsException
+	 */
+	public function parseDeletedMessage(Message $chatMessage): void {
+		$this->l = $chatMessage->getL10n();
+		$data = json_decode($chatMessage->getMessage(), true);
+		if (!\is_array($data)) {
+			throw new \OutOfBoundsException('Invalid message');
+		}
+
+		$parsedParameters = ['actor' => $this->getActor($data['deleted_by_type'], $data['deleted_by_id'])];
+
+		$participant = $chatMessage->getParticipant();
+		$currentActorId = $participant->getAttendee()->getActorId();
+
+		$authorIsActor = $data['deleted_by_type'] === $chatMessage->getComment()->getActorType()
+			&& $data['deleted_by_id'] === $chatMessage->getComment()->getActorId();
+
+		if (!$participant->isGuest()) {
+			$currentUserIsActor = $parsedParameters['actor']['type'] === 'user' &&
+				$participant->getAttendee()->getActorType() === Attendee::ACTOR_USERS &&
+				$currentActorId === $parsedParameters['actor']['id'];
+		} else {
+			$currentUserIsActor = $parsedParameters['actor']['type'] === 'guest' &&
+				$participant->getAttendee()->getActorType() === 'guest' &&
+				$currentActorId === $parsedParameters['actor']['id'];
+		}
+
+		if ($chatMessage->getMessageType() === 'comment_deleted') {
+			$message = 'message_deleted';
+			$parsedMessage = $this->l->t('Message deleted by author');
+
+			if (!$authorIsActor) {
+				$parsedMessage = $this->l->t('Message deleted by {actor}');
+			}
+			if ($currentUserIsActor) {
+				$parsedMessage = $this->l->t('Message deleted by you');
+			}
 		} else {
 			throw new \OutOfBoundsException('Unknown subject');
 		}
@@ -430,12 +481,16 @@ protected function getFileFromShare(Participant $participant, string $shareId):
 		];
 	}
 
-	protected function getActor(IComment $comment): array {
-		if ($comment->getActorType() === Attendee::ACTOR_GUESTS) {
-			return $this->getGuest($comment->getActorId());
+	protected function getActorFromComment(IComment $comment): array {
+		return $this->getActor($comment->getActorType(), $comment->getActorId());
+	}
+
+	protected function getActor(string $actorType, string $actorId): array {
+		if ($actorType === Attendee::ACTOR_GUESTS) {
+			return $this->getGuest($actorId);
 		}
 
-		return $this->getUser($comment->getActorId());
+		return $this->getUser($actorId);
 	}
 
 	protected function getUser(string $uid): array {

lib/Controller/ChatController.php

@@ -29,6 +29,7 @@
 use OCA\Talk\Chat\ChatManager;
 use OCA\Talk\Chat\MessageParser;
 use OCA\Talk\GuestManager;
+use OCA\Talk\MatterbridgeManager;
 use OCA\Talk\Model\Attendee;
 use OCA\Talk\Model\Message;
 use OCA\Talk\Model\Session;
@@ -92,6 +93,9 @@ class ChatController extends AEnvironmentAwareController {
 	/** @var IUserStatusManager */
 	private $statusManager;
 
+	/** @var MatterbridgeManager */
+	protected $matterbridgeManager;
+
 	/** @var SearchPlugin */
 	private $searchPlugin;
 
@@ -120,6 +124,7 @@ public function __construct(string $appName,
 								MessageParser $messageParser,
 								IManager $autoCompleteManager,
 								IUserStatusManager $statusManager,
+								MatterbridgeManager $matterbridgeManager,
 								SearchPlugin $searchPlugin,
 								ISearchResult $searchResult,
 								ITimeFactory $timeFactory,
@@ -138,6 +143,7 @@ public function __construct(string $appName,
 		$this->messageParser = $messageParser;
 		$this->autoCompleteManager = $autoCompleteManager;
 		$this->statusManager = $statusManager;
+		$this->matterbridgeManager = $matterbridgeManager;
 		$this->searchPlugin = $searchPlugin;
 		$this->searchResult = $searchResult;
 		$this->timeFactory = $timeFactory;
@@ -462,6 +468,69 @@ public function receiveMessages(int $lookIntoFuture,
 		return $response;
 	}
 
+	/**
+	 * @NoAdminRequired
+	 * @RequireParticipant
+	 * @RequireReadWriteConversation
+	 * @RequireModeratorOrNoLobby
+	 *
+	 * @param int $messageId
+	 * @return DataResponse
+	 */
+	public function deleteMessage(int $messageId): DataResponse {
+		try {
+			$message = $this->chatManager->getComment($this->room, (string) $messageId);
+		} catch (NotFoundException $e) {
+			return new DataResponse([], Http::STATUS_NOT_FOUND);
+		}
+
+		$attendee = $this->participant->getAttendee();
+		if (!$this->participant->hasModeratorPermissions(false)
+			&& ($message->getActorType() !== $attendee->getActorType()
+				|| $message->getActorId() !== $attendee->getActorId())) {
+			// Actor is not a moderator or not the owner of the message
+			return new DataResponse([], Http::STATUS_FORBIDDEN);
+		}
+
+		if ($message->getVerb() !== 'comment') {
+			// System message or file share (since the message is not parsed, it has type "system")
+			return new DataResponse([], Http::STATUS_METHOD_NOT_ALLOWED);
+		}
+
+		$maxDeleteAge = $this->timeFactory->getDateTime();
+		$maxDeleteAge->sub(new \DateInterval('PT6H'));
+		if ($message->getCreationDateTime() < $maxDeleteAge) {
+			// Message is too old
+			return new DataResponse([], Http::STATUS_BAD_REQUEST);
+		}
+
+		$systemMessageComment = $this->chatManager->deleteMessage(
+			$this->room,
+			$messageId,
+			$attendee->getActorType(),
+			$attendee->getActorId(),
+			$this->timeFactory->getDateTime()
+		);
+
+		$systemMessage = $this->messageParser->createMessage($this->room, $this->participant, $systemMessageComment, $this->l);
+		$this->messageParser->parseMessage($systemMessage);
+
+		$comment = $this->chatManager->getComment($this->room, (string) $messageId);
+		$message = $this->messageParser->createMessage($this->room, $this->participant, $comment, $this->l);
+		$this->messageParser->parseMessage($message);
+
+		$data = $systemMessage->toArray();
+		$data['parent'] = $message->toArray();
+
+		$bridge = $this->matterbridgeManager->getBridgeOfRoom($this->room);
+
+		$response = new DataResponse($data, $bridge['enabled'] ? Http::STATUS_ACCEPTED: Http::STATUS_OK);
+		if ($this->participant->getAttendee()->getReadPrivacy() === Participant::PRIVACY_PUBLIC) {
+			$response->addHeader('X-Chat-Last-Common-Read', $this->chatManager->getLastCommonReadMessage($this->room));
+		}
+		return $response;
+	}
+
 	/**
 	 * @NoAdminRequired
 	 * @RequireParticipant