Function serveFile

packages/socket.io/lib/uws.ts:127–168

(res /* : HttpResponse */, filepath: string)

// imported from https://github.com/kolodziejczak-sz/uwebsocket-serve
export function serveFile(res /* : HttpResponse */, filepath: string) {
  const { size } = statSync(filepath);
  const readStream = createReadStream(filepath);
  const destroyReadStream = () => !readStream.destroyed && readStream.destroy();

  const onError = (error: Error) => {
    destroyReadStream();
    throw error;
  };

  const onDataChunk = (chunk: Buffer) => {
    const arrayBufferChunk = toArrayBuffer(chunk);

    res.cork(() => {
      const lastOffset = res.getWriteOffset();
      const [ok, done] = res.tryEnd(arrayBufferChunk, size);

      if (!done && !ok) {
        readStream.pause();

        res.onWritable((offset) => {
          const [ok, done] = res.tryEnd(
            arrayBufferChunk.slice(offset - lastOffset),
            size,
          );

          if (!done && ok) {
            readStream.resume();
          }

          return ok;
        });
      }
    });
  };

  res.onAborted(destroyReadStream);
  readStream
    .on("data", onDataChunk)
    .on("error", onError)
    .on("end", destroyReadStream);
}