Function downloadToFile

packages/cli/src/cloud/download.ts:39–98

(
  url: string,
  destPath: string,
  options: DownloadOptions = {},
)

 */
// fallow-ignore-next-line complexity
export async function downloadToFile(
  url: string,
  destPath: string,
  options: DownloadOptions = {},
): Promise<DownloadResult> {
  const fetchImpl = options.fetchImpl ?? fetch;
  const res = await fetchImpl(url, { signal: options.signal });
  if (!res.ok) {
    throw new Error(`Failed to download ${url}: HTTP ${res.status} ${res.statusText}`);
  }
  if (!res.body) {
    throw new Error(`Failed to download ${url}: empty response body`);
  }

  mkdirSync(dirname(destPath), { recursive: true });

  const totalHeader = res.headers.get("content-length");
  const total = totalHeader ? Number.parseInt(totalHeader, 10) : undefined;
  const totalOpt = total !== undefined && Number.isFinite(total) ? total : undefined;

  const file = createWriteStream(destPath);
  let bytes = 0;
  let errored = false;
  try {
    for await (const chunk of res.body as unknown as AsyncIterable<Uint8Array>) {
      if (options.signal?.aborted) {
        throw options.signal.reason instanceof Error
          ? options.signal.reason
          : new Error("Download aborted");
      }
      bytes += chunk.byteLength;
      options.onProgress?.(bytes, totalOpt);
      if (!file.write(chunk)) {
        await waitForDrain(file, options.signal);
      }
    }
    if (totalOpt !== undefined && bytes !== totalOpt) {
      throw new Error(
        `Truncated download: got ${bytes} bytes, expected ${totalOpt} (content-length). ` +
          `The presigned URL may have expired mid-transfer — refetch via \`hyperframes cloud get\`.`,
      );
    }
  } catch (err) {
    errored = true;
    throw err;
  } finally {
    await closeFile(file);
    if (errored) {
      // Don't let a partial file pose as the final artifact. Best-
      // effort unlink — if it fails (already gone, permission), we
      // re-throw the original error.
      try {
        unlinkSync(destPath);
      } catch {
        /* swallow */
      }
    }
  }