__init__.py 文件源码

def resolve_adapter(uri):
  # type: (AdapterSpec) -> BaseAdapter
  """
  Given a URI, returns a properly-configured adapter instance.
  """
  if isinstance(uri, BaseAdapter):
    return uri

  parsed = compat.urllib_parse.urlsplit(uri) # type: SplitResult

  if not parsed.scheme:
    raise with_context(
      exc = InvalidUri(
        'URI must begin with "<protocol>://" (e.g., "udp://").',
      ),

      context = {
        'parsed': parsed,
        'uri':    uri,
      },
    )

  try:
    adapter_type = adapter_registry[parsed.scheme]
  except KeyError:
    raise with_context(
      exc = InvalidUri('Unrecognized protocol {protocol!r}.'.format(
        protocol = parsed.scheme,
      )),

      context = {
        'parsed': parsed,
        'uri':    uri,
      },
    )

  return adapter_type.configure(parsed)