# Copyright 2016 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Transport adapter for Requests."""
from __future__ import absolute_import
import functools
import logging
try:
import requests
except ImportError as caught_exc: # pragma: NO COVER
import six
six.raise_from(
ImportError(
'The requests library is not installed, please install the '
'requests package to use the requests transport.'
),
caught_exc,
)
import requests.adapters # pylint: disable=ungrouped-imports
import requests.exceptions # pylint: disable=ungrouped-imports
import six # pylint: disable=ungrouped-imports
from google.auth import exceptions
from google.auth import transport
_LOGGER = logging.getLogger(__name__)
class _Response(transport.Response):
"""Requests transport response adapter.
Args:
response (requests.Response): The raw Requests response.
"""
def __init__(self, response):
self._response = response
@property
def status(self):
return self._response.status_code
@property
def headers(self):
return self._response.headers
@property
def data(self):
return self._response.content
class Request(transport.Request):
"""Requests request adapter.
This class is used internally for making requests using various transports
in a consistent way. If you use :class:`AuthorizedSession` you do not need
to construct or use this class directly.
This class can be useful if you want to manually refresh a
:class:`~google.auth.credentials.Credentials` instance::
import google.auth.transport.requests
import requests
request = google.auth.transport.requests.Request()
credentials.refresh(request)
Args:
session (requests.Session): An instance :class:`requests.Session` used
to make HTTP requests. If not specified, a session will be created.
.. automethod:: __call__
"""
def __init__(self, session=None):
if not session:
session = requests.Session()
self.session = session
def __call__(self, url, method='GET', body=None, headers=None,
timeout=None, **kwargs):
"""Make an HTTP request using requests.
Args:
url (str): The URI to be requested.
method (str): The HTTP method to use for the request. Defaults
to 'GET'.
body (bytes): The payload / body in HTTP request.
headers (Mapping[str, str]): Request headers.
timeout (Optional[int]): The number of seconds to wait for a
response from the server. If not specified or if None, the
requests default timeout will be used.
kwargs: Additional arguments passed through to the underlying
requests :meth:`~requests.Session.request` method.
Returns:
google.auth.transport.Response: The HTTP response.
Raises:
google.auth.exceptions.TransportError: If any exception occurred.
"""
try:
_LOGGER.debug('Making request: %s %s', method, url)
response = self.session.request(
method, url, data=body, headers=headers, timeout=timeout,
**kwargs)
return _Response(response)
except requests.exceptions.RequestException as caught_exc:
new_exc = exceptions.TransportError(caught_exc)
six.raise_from(new_exc, caught_exc)
class AuthorizedSession(requests.Session):
"""A Requests Session class with credentials.
This class is used to perform requests to API endpoints that require
authorization::
from google.auth.transport.requests import AuthorizedSession
authed_session = AuthorizedSession(credentials)
response = authed_session.request(
'GET', 'https://www.googleapis.com/storage/v1/b')
The underlying :meth:`request` implementation handles adding the
credentials' headers to the request and refreshing credentials as needed.
Args:
credentials (google.auth.credentials.Credentials): The credentials to
add to the request.
refresh_status_codes (Sequence[int]): Which HTTP status codes indicate
that credentials should be refreshed and the request should be
retried.
max_refresh_attempts (int): The maximum number of times to attempt to
refresh the credentials and retry the request.
refresh_timeout (Optional[int]): The timeout value in seconds for
credential refresh HTTP requests.
kwargs: Additional arguments passed to the :class:`requests.Session`
constructor.
"""
def __init__(self, credentials,
refresh_status_codes=transport.DEFAULT_REFRESH_STATUS_CODES,
max_refresh_attempts=transport.DEFAULT_MAX_REFRESH_ATTEMPTS,
refresh_timeout=None,
**kwargs):
super(AuthorizedSession, self).__init__(**kwargs)
self.credentials = credentials
self._refresh_status_codes = refresh_status_codes
self._max_refresh_attempts = max_refresh_attempts
self._refresh_timeout = refresh_timeout
auth_request_session = requests.Session()
# Using an adapter to make HTTP requests robust to network errors.
# This adapter retrys HTTP requests when network errors occur
# and the requests seems safely retryable.
retry_adapter = requests.adapters.HTTPAdapter(max_retries=3)
auth_request_session.mount("https://", retry_adapter)
# Request instance used by internal methods (for example,
# credentials.refresh).
# Do not pass `self` as the session here, as it can lead to infinite
# recursion.
self._auth_request = Request(auth_request_session)
def request(self, method, url, data=None, headers=None, **kwargs):
"""Implementation of Requests' request."""
# pylint: disable=arguments-differ
# Requests has a ton of arguments to request, but only two
# (method, url) are required. We pass through all of the other
# arguments to super, so no need to exhaustively list them here.
# Use a kwarg for this instead of an attribute to maintain
# thread-safety.
_credential_refresh_attempt = kwargs.pop(
'_credential_refresh_attempt', 0)
# Make a copy of the headers. They will be modified by the credentials
# and we want to pass the original headers if we recurse.
request_headers = headers.copy() if headers is not None else {}
self.credentials.before_request(
self._auth_request, method, url, request_headers)
response = super(AuthorizedSession, self).request(
method, url, data=data, headers=request_headers, **kwargs)
# If the response indicated that the credentials needed to be
# refreshed, then refresh the credentials and re-attempt the
# request.
# A stored token may expire between the time it is retrieved and
# the time the request is made, so we may need to try twice.
if (response.status_code in self._refresh_status_codes
and _credential_refresh_attempt < self._max_refresh_attempts):
_LOGGER.info(
'Refreshing credentials due to a %s response. Attempt %s/%s.',
response.status_code, _credential_refresh_attempt + 1,
self._max_refresh_attempts)
auth_request_with_timeout = functools.partial(
self._auth_request, timeout=self._refresh_timeout)
self.credentials.refresh(auth_request_with_timeout)
# Recurse. Pass in the original headers, not our modified set.
return self.request(
method, url, data=data, headers=headers,
_credential_refresh_attempt=_credential_refresh_attempt + 1,
**kwargs)
return response
