Function serveFile

lib/uws.ts:125–164

(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);

    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);
}