nextcloud/server · error · Sabre\DAV\Exception\BadRequest

Message exceeds allowed character limit of 1000

Error message

Message exceeds allowed character limit of 1000

What it means

Comments are capped at IComment::MAX_MESSAGE_LENGTH, which is 1000 characters. Comment::setMessage() throws MessageTooLongException for longer strings, and the DAV plugin converts it into a 400 response that names the limit. The limit applies to the decoded message string, not to the raw request size.

Solutions

1. Validate and cap the message to 1000 characters client-side before sending.
2. Split longer content into multiple comments, or store the long text elsewhere and post a short comment linking to it.
3. Use mb_strlen($message, 'UTF-8') so the client count matches the server's character-based count.

Example fix

// before: HTTP 400 Message exceeds allowed character limit of 1000
$payload['message'] = $userText;

// after: cap at the server limit, counted in characters
$max = 1000; // IComment::MAX_MESSAGE_LENGTH
$payload['message'] = mb_strlen($userText, 'UTF-8') > $max
    ? mb_substr($userText, 0, $max, 'UTF-8')
    : $userText;

$max = 1000; // IComment::MAX_MESSAGE_LENGTH
if (mb_strlen($payload['message'], 'UTF-8') > $max) {
    $payload['message'] = mb_substr($payload['message'], 0, $max, 'UTF-8');
    // or reject: throw new MessageTooLongClientError();
}

try {
    $client->request('POST', $commentsUrl, $body);
} catch (ClientHttpException $e) {
    if ($e->getResponse()->getStatusCode() === 400
        && str_contains($e->getResponse()->getBody()->getContents(), 'character limit')) {
        $payload['message'] = mb_substr($payload['message'], 0, 1000, 'UTF-8');
        $client->request('POST', $commentsUrl, json_encode($payload));
    }
}

When it happens

Trigger: POST (create) or PUT (edit) of a comment whose message field exceeds 1000 characters after JSON decoding; multi-byte text is measured in characters, not bytes.

Common situations: Pasting long text into comment UIs; clients that count bytes instead of characters on UTF-8 content and therefore underestimate the length; concatenating templated messages client-side without a cap.

Related errors

• Message exceeds allowed character limit of 1000
• Invalid input values
• Cannot create comments by id
• Entity does not exist or is not available
• Entity type "$name" not found."

AI-assisted analysis of nextcloud/server@ecdeb153ff (2026-08-17). Data as JSON: /api/errors/bb22c1292687780f. Report an issue: GitHub.

Appendix: source

Thrown at apps/dav/lib/Comments/CommentsPlugin.php:233

			if (!is_null($user)) {
				$actorId = $user->getUID();
			}
		}
		if (is_null($actorId)) {
			throw new BadRequest('Invalid actor "' . $actorType . '"');
		}

		try {
			$comment = $this->commentsManager->create($actorType, $actorId, $objectType, $objectId);
			$comment->setMessage($data['message']);
			$comment->setVerb($data['verb']);
			$this->commentsManager->save($comment);
			return $comment;
		} catch (\InvalidArgumentException $e) {
			throw new BadRequest('Invalid input values', 0, $e);
		} catch (MessageTooLongException $e) {
			$msg = 'Message exceeds allowed character limit of ';
			throw new BadRequest($msg . IComment::MAX_MESSAGE_LENGTH, 0, $e);
		}
	}
}

View on GitHub (pinned to ecdeb153ff)