def open()

in server/scripts/cloudstorage/cloudstorage_api.py [0:0]

• 23 lines of code
• 5 McCabe index (conditional complexity)

def open(filename,
         mode='r',
         content_type=None,
         options=None,
         read_buffer_size=storage_api.ReadBuffer.DEFAULT_BUFFER_SIZE,
         retry_params=None,
         _account_id=None):
  """Opens a Google Cloud Storage file and returns it as a File-like object.

  Args:
    filename: A Google Cloud Storage filename of form '/bucket/filename'.
    mode: 'r' for reading mode. 'w' for writing mode.
      In reading mode, the file must exist. In writing mode, a file will
      be created or be overrode.
    content_type: The MIME type of the file. str. Only valid in writing mode.
    options: A str->basestring dict to specify additional headers to pass to
      GCS e.g. {'x-goog-acl': 'private', 'x-goog-meta-foo': 'foo'}.
      Supported options are x-goog-acl, x-goog-meta-, cache-control,
      content-disposition, and content-encoding.
      Only valid in writing mode.
      See https://developers.google.com/storage/docs/reference-headers
      for details.
    read_buffer_size: The buffer size for read. Read keeps a buffer
      and prefetches another one. To minimize blocking for large files,
      always read by buffer size. To minimize number of RPC requests for
      small files, set a large buffer size. Max is 30MB.
    retry_params: An instance of api_utils.RetryParams for subsequent calls
      to GCS from this file handle. If None, the default one is used.
    _account_id: Internal-use only.

  Returns:
    A reading or writing buffer that supports File-like interface. Buffer
    must be closed after operations are done.

  Raises:
    errors.AuthorizationError: if authorization failed.
    errors.NotFoundError: if an object that's expected to exist doesn't.
    ValueError: invalid open mode or if content_type or options are specified
      in reading mode.
  """
  common.validate_file_path(filename)
  api = storage_api._get_storage_api(retry_params=retry_params,
                                     account_id=_account_id)
  filename = api_utils._quote_filename(filename)

  if mode == 'w':
    common.validate_options(options)
    return storage_api.StreamingBuffer(api, filename, content_type, options)
  elif mode == 'r':
    if content_type or options:
      raise ValueError('Options and content_type can only be specified '
                       'for writing mode.')
    return storage_api.ReadBuffer(api,
                                  filename,
                                  buffer_size=read_buffer_size)
  else:
    raise ValueError('Invalid mode %s.' % mode)