message: remove cache prevention
diff: @@ -322,8 +322,8 @@ export class DownloadController {
  data.courseName += 'Single';
  const hash = await this.createFileHash(data);
  - // const key = cache.get(hash);
  - const key = null;
  + const key = cache.get(hash);
  +
  if (key === null) {
  const filepath = config.tmpFileCacheFolder + hash + '.zip';
  const output = fs.createWriteStream(filepath);
  