OtterMind/Chat2DB · error · RequestError

message is too long

Error message

message is too long

What it means

Raised at relay_server.py:227 when len(message) > config.max_message_length. The cap defaults to 900 (RelayConfig.max_message_length) and is read from the RELAY_MAX_MESSAGE_LENGTH environment variable. It protects the QQ/NapCat group message size limit. len() counts Unicode code points, not bytes. Returned as HTTP 400.

Source

Thrown at script/github/qq_relay/relay_server.py:228

            payload = json.loads(self.rfile.read(content_length).decode("utf-8"))
        except (UnicodeDecodeError, json.JSONDecodeError) as error:
            raise RequestError(HTTPStatus.BAD_REQUEST, "request body is not valid JSON") from error
        if not isinstance(payload, Mapping):
            raise RequestError(HTTPStatus.BAD_REQUEST, "request body must be a JSON object")
        return payload

    def _validate_payload(self, payload: Mapping[str, Any]) -> tuple[str, str]:
        config = self.relay_state.config
        if payload.get("repository") != config.repository:
            raise RequestError(HTTPStatus.FORBIDDEN, "repository is not allowed")
        delivery_id = payload.get("delivery_id")
        if not isinstance(delivery_id, str) or not DELIVERY_ID_PATTERN.fullmatch(delivery_id):
            raise RequestError(HTTPStatus.BAD_REQUEST, "delivery_id is invalid")
        message = payload.get("message")
        if not isinstance(message, str) or not message.strip():
            raise RequestError(HTTPStatus.BAD_REQUEST, "message must be non-empty text")
        if len(message) > config.max_message_length:
            raise RequestError(HTTPStatus.BAD_REQUEST, "message is too long")
        if CONTROL_CHARACTER_PATTERN.search(message):
            raise RequestError(HTTPStatus.BAD_REQUEST, "message contains control characters")
        return delivery_id, message

    def do_GET(self) -> None:  # noqa: N802
        if self.path == "/healthz":
            self._send_json(HTTPStatus.OK, {"ok": True})
            return
        self._send_json(HTTPStatus.NOT_FOUND, {"error": "not found"})

    def do_POST(self) -> None:  # noqa: N802
        delivery_id = ""
        reserved = False
        try:
            if self.path != "/v1/qq/github":
                raise RequestError(HTTPStatus.NOT_FOUND, "not found")
            self._authorize()
            delivery_id, message = self._validate_payload(self._read_payload())

View on GitHub (pinned to 5ee1e990e7)

Solutions

  1. Truncate the message to <= max_message_length code points on the sender before posting.
  2. Raise RELAY_MAX_MESSAGE_LENGTH on the relay to stay within QQ's real limit.
  3. Split very long content into multiple deliveries with distinct delivery_ids.

Example fix

# before
payload["message"] = long_text
# after
payload["message"] = long_text[:900]  # or read RELAY_MAX_MESSAGE_LENGTH from relay
Defensive patterns

Strategy: validation

Validate before calling

max_len = int(os.environ.get('RELAY_MAX_MESSAGE_LENGTH', '900'))
payload['message'] = payload['message'][:max_len]

Type guard

def message_within_limit(payload: dict, limit: int) -> bool:
    msg = payload.get('message')
    return isinstance(msg, str) and len(msg) <= limit

Try / catch

resp = requests.post(url, json=payload)
if resp.status_code == 400 and resp.json().get('error') == 'message is too long':
    payload['message'] = payload['message'][:900]
    resp = requests.post(url, json=payload)

Prevention

When it happens

Trigger: A single delivery whose message text is longer than the configured cap, e.g. a full commit diff, log dump, or concatenated PR body forwarded as one message.

Common situations: Default 900 is too small for verbose events and RELAY_MAX_MESSAGE_LENGTH was not raised; sender forwards raw artifact text without truncation; emoji/CJK counts as one code point each so byte-based truncation underestimates.

Related errors

AI-assisted analysis of OtterMind/Chat2DB@5ee1e990e7 (2026-08-14). Data as JSON: /api/errors/3c119f54e4ab00e8. Report an issue: GitHub.