rohitg00/ai-engineering-from-scratch · error · ValueError

request body ended before Content-Length bytes arrived

Error message

request body ended before Content-Length bytes arrived

What it means

Error "request body ended before Content-Length bytes arrived" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/13-tools-and-protocols/09-mcp-transports/code/main.py:423

        if "application/json" not in accept or "text/event-stream" not in accept:
            self._write_json(406, {"error": "Accept must include JSON and SSE"})
            return
        try:
            reject_ambiguous_body_framing(self.headers)
            raw_length = self.headers.get("Content-Length")
            if raw_length is None:
                raise ValueError("Content-Length is required")
            if not raw_length.isascii() or not raw_length.isdigit():
                raise ValueError("Content-Length must contain ASCII decimal digits")
            length = int(raw_length)
            if not 1 <= length <= MAX_REQUEST_BYTES:
                raise ValueError(
                    f"Content-Length must be from 1 through {MAX_REQUEST_BYTES}"
                )
            self.connection.settimeout(READ_TIMEOUT_SECONDS)
            body = self.rfile.read(length)
            if len(body) != length:
                raise ValueError("request body ended before Content-Length bytes arrived")
            message = json.loads(body)
            if not isinstance(message, dict):
                raise ValueError("message must be an object")
        except (ValueError, json.JSONDecodeError, TimeoutError) as exc:
            self._write_json(400, rpc_error(None, -32700, "Parse error", {"detail": str(exc)}))
            return

        request_id = message.get("id")
        try:
            body_version = validate_request_structure(message)
            reject_duplicate_routing_headers(self.headers)
            validate_http_headers(self.headers, message, body_version)
            validate_supported_version(body_version)
        except RpcFault as fault:
            self._write_fault(400, request_id, fault)
            return

        if "id" not in message:

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/13-tools-and-protocols/09-mcp-transports/code/main.py:423 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/0efaba79f81fd54b. Report an issue: GitHub.