base.py 文件源码

def maybe_download(filename, work_directory, source_url):
  """Download the data from source url, unless it's already here.

  Args:
      filename: string, name of the file in the directory.
      work_directory: string, path to working directory.
      source_url: url to download from if file doesn't exist.

  Returns:
      Path to resulting file.
  """
  if not gfile.Exists(work_directory):
    gfile.MakeDirs(work_directory)
  filepath = os.path.join(work_directory, filename)
  if not gfile.Exists(filepath):
    with tempfile.NamedTemporaryFile() as tmpfile:
      temp_file_name = tmpfile.name
      urllib.request.urlretrieve(source_url, temp_file_name)
      gfile.Copy(temp_file_name, filepath)
      with gfile.GFile(filepath) as f:
        size = f.size()
      print('Successfully downloaded', filename, size, 'bytes.')
  return filepath