code: def show_release_file(root, request):
      
      settings = request.registry.settings
      whlify = asbool(settings.get('pyshop.mirror.wheelify', '0'))
      session = DBSession()
  
      f = ReleaseFile.by_id(session, int(request.matchdict['file_id']))
      whlify = whlify and f.package_type == 'sdist'
  
      filename = f.filename_whlified if whlify else f.filename
      url = f.url
      if url and url.startswith('http://pypi.python.org'):
          url = 'https' + url[4:]
  
      rv = {'url': url,
            'filename': filename,
            'original': f.filename,
            'whlify': whlify
            }
      f.downloads += 1
      f.release.downloads += 1
      f.release.package.downloads += 1
      session.add(f.release.package)
      session.add(f.release)
      session.add(f)
      request.response.etag = f.md5_digest
      request.response.cache_control = 'max-age=31557600, public'
      request.response.date = datetime.datetime.utcnow()
      return rv
docs: Download a release file.
      Must be used with :func:`pyshop.helpers.download.renderer_factory`
      to download the release file.
  
      :return: download informations
      :rtype: dict