openclaw/scripts/lib/bounded-response.ts

export async function readBoundedResponseText(
  response: Response,
  label: string,
  maxBytes: number,
): Promise<string> {
  const contentLength = Number.parseInt(response.headers.get("content-length") ?? "", 10);
  if (Number.isFinite(contentLength) && contentLength > maxBytes) {
    throw new Error(`${label} response body exceeded ${maxBytes} bytes.`);
  }

  if (!response.body) {
    return "";
  }

  const reader = response.body.getReader();
  const decoder = new TextDecoder();
  const chunks: string[] = [];
  let totalBytes = 0;
  let canceled = false;

  try {
    for (;;) {
      const { done, value } = await reader.read();
      if (done) {
        const tail = decoder.decode();
        if (tail) {
          chunks.push(tail);
        }
        break;
      }

      totalBytes += value.byteLength;
      if (totalBytes > maxBytes) {
        canceled = true;
        await reader.cancel().catch(() => undefined);
        throw new Error(`${label} response body exceeded ${maxBytes} bytes.`);
      }
      chunks.push(decoder.decode(value, { stream: true }));
    }
  } finally {
    if (!canceled) {
      reader.releaseLock();
    }
  }

  return chunks.join("");
}