# Copyright 2016 Google LLC
#
# 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.
"""OAuth 2.0 Credentials.
This module provides credentials based on OAuth 2.0 access and refresh tokens.
These credentials usually access resources on behalf of a user (resource
owner).
Specifically, this is intended to use access tokens acquired using the
`Authorization Code grant`_ and can refresh those tokens using a
optional `refresh token`_.
Obtaining the initial access and refresh token is outside of the scope of this
module. Consult `rfc6749 section 4.1`_ for complete details on the
Authorization Code grant flow.
.. _Authorization Code grant: https://tools.ietf.org/html/rfc6749#section-1.3.1
.. _refresh token: https://tools.ietf.org/html/rfc6749#section-6
.. _rfc6749 section 4.1: https://tools.ietf.org/html/rfc6749#section-4.1
"""
from datetime import datetime
import io
import json
import six
from google.auth import _cloud_sdk
from google.auth import _helpers
from google.auth import credentials
from google.auth import exceptions
from google.oauth2 import reauth
# The Google OAuth 2.0 token endpoint. Used for authorized user credentials.
_GOOGLE_OAUTH2_TOKEN_ENDPOINT = "https://oauth2.googleapis.com/token"
[docs]class Credentials(credentials.ReadOnlyScoped, credentials.CredentialsWithQuotaProject):
"""Credentials using OAuth 2.0 access and refresh tokens.
The credentials are considered immutable. If you want to modify the
quota project, use :meth:`with_quota_project` or ::
credentials = credentials.with_quota_project('myproject-123')
Reauth is disabled by default. To enable reauth, set the
`enable_reauth_refresh` parameter to True in the constructor. Note that
reauth feature is intended for gcloud to use only.
If reauth is enabled, `pyu2f` dependency has to be installed in order to use security
key reauth feature. Dependency can be installed via `pip install pyu2f` or `pip install
google-auth[reauth]`.
"""
def __init__(
self,
token,
refresh_token=None,
id_token=None,
token_uri=None,
client_id=None,
client_secret=None,
scopes=None,
default_scopes=None,
quota_project_id=None,
expiry=None,
rapt_token=None,
refresh_handler=None,
enable_reauth_refresh=False,
):
"""
Args:
token (Optional(str)): The OAuth 2.0 access token. Can be None
if refresh information is provided.
refresh_token (str): The OAuth 2.0 refresh token. If specified,
credentials can be refreshed.
id_token (str): The Open ID Connect ID Token.
token_uri (str): The OAuth 2.0 authorization server's token
endpoint URI. Must be specified for refresh, can be left as
None if the token can not be refreshed.
client_id (str): The OAuth 2.0 client ID. Must be specified for
refresh, can be left as None if the token can not be refreshed.
client_secret(str): The OAuth 2.0 client secret. Must be specified
for refresh, can be left as None if the token can not be
refreshed.
scopes (Sequence[str]): The scopes used to obtain authorization.
This parameter is used by :meth:`has_scopes`. OAuth 2.0
credentials can not request additional scopes after
authorization. The scopes must be derivable from the refresh
token if refresh information is provided (e.g. The refresh
token scopes are a superset of this or contain a wild card
scope like 'https://www.googleapis.com/auth/any-api').
default_scopes (Sequence[str]): Default scopes passed by a
Google client library. Use 'scopes' for user-defined scopes.
quota_project_id (Optional[str]): The project ID used for quota and billing.
This project may be different from the project used to
create the credentials.
rapt_token (Optional[str]): The reauth Proof Token.
refresh_handler (Optional[Callable[[google.auth.transport.Request, Sequence[str]], [str, datetime]]]):
A callable which takes in the HTTP request callable and the list of
OAuth scopes and when called returns an access token string for the
requested scopes and its expiry datetime. This is useful when no
refresh tokens are provided and tokens are obtained by calling
some external process on demand. It is particularly useful for
retrieving downscoped tokens from a token broker.
enable_reauth_refresh (Optional[bool]): Whether reauth refresh flow
should be used. This flag is for gcloud to use only.
"""
super(Credentials, self).__init__()
self.token = token
self.expiry = expiry
self._refresh_token = refresh_token
self._id_token = id_token
self._scopes = scopes
self._default_scopes = default_scopes
self._token_uri = token_uri
self._client_id = client_id
self._client_secret = client_secret
self._quota_project_id = quota_project_id
self._rapt_token = rapt_token
self.refresh_handler = refresh_handler
self._enable_reauth_refresh = enable_reauth_refresh
def __getstate__(self):
"""A __getstate__ method must exist for the __setstate__ to be called
This is identical to the default implementation.
See https://docs.python.org/3.7/library/pickle.html#object.__setstate__
"""
state_dict = self.__dict__.copy()
# Remove _refresh_handler function as there are limitations pickling and
# unpickling certain callables (lambda, functools.partial instances)
# because they need to be importable.
# Instead, the refresh_handler setter should be used to repopulate this.
del state_dict["_refresh_handler"]
return state_dict
def __setstate__(self, d):
"""Credentials pickled with older versions of the class do not have
all the attributes."""
self.token = d.get("token")
self.expiry = d.get("expiry")
self._refresh_token = d.get("_refresh_token")
self._id_token = d.get("_id_token")
self._scopes = d.get("_scopes")
self._default_scopes = d.get("_default_scopes")
self._token_uri = d.get("_token_uri")
self._client_id = d.get("_client_id")
self._client_secret = d.get("_client_secret")
self._quota_project_id = d.get("_quota_project_id")
self._rapt_token = d.get("_rapt_token")
self._enable_reauth_refresh = d.get("_enable_reauth_refresh")
# The refresh_handler setter should be used to repopulate this.
self._refresh_handler = None
@property
def refresh_token(self):
"""Optional[str]: The OAuth 2.0 refresh token."""
return self._refresh_token
@property
def scopes(self):
"""Optional[str]: The OAuth 2.0 permission scopes."""
return self._scopes
@property
def token_uri(self):
"""Optional[str]: The OAuth 2.0 authorization server's token endpoint
URI."""
return self._token_uri
@property
def id_token(self):
"""Optional[str]: The Open ID Connect ID Token.
Depending on the authorization server and the scopes requested, this
may be populated when credentials are obtained and updated when
:meth:`refresh` is called. This token is a JWT. It can be verified
and decoded using :func:`google.oauth2.id_token.verify_oauth2_token`.
"""
return self._id_token
@property
def client_id(self):
"""Optional[str]: The OAuth 2.0 client ID."""
return self._client_id
@property
def client_secret(self):
"""Optional[str]: The OAuth 2.0 client secret."""
return self._client_secret
@property
def requires_scopes(self):
"""False: OAuth 2.0 credentials have their scopes set when
the initial token is requested and can not be changed."""
return False
@property
def rapt_token(self):
"""Optional[str]: The reauth Proof Token."""
return self._rapt_token
@property
def refresh_handler(self):
"""Returns the refresh handler if available.
Returns:
Optional[Callable[[google.auth.transport.Request, Sequence[str]], [str, datetime]]]:
The current refresh handler.
"""
return self._refresh_handler
@refresh_handler.setter
def refresh_handler(self, value):
"""Updates the current refresh handler.
Args:
value (Optional[Callable[[google.auth.transport.Request, Sequence[str]], [str, datetime]]]):
The updated value of the refresh handler.
Raises:
TypeError: If the value is not a callable or None.
"""
if not callable(value) and value is not None:
raise TypeError("The provided refresh_handler is not a callable or None.")
self._refresh_handler = value
[docs] @_helpers.copy_docstring(credentials.CredentialsWithQuotaProject)
def with_quota_project(self, quota_project_id):
return self.__class__(
self.token,
refresh_token=self.refresh_token,
id_token=self.id_token,
token_uri=self.token_uri,
client_id=self.client_id,
client_secret=self.client_secret,
scopes=self.scopes,
default_scopes=self.default_scopes,
quota_project_id=quota_project_id,
rapt_token=self.rapt_token,
enable_reauth_refresh=self._enable_reauth_refresh,
)
[docs] @_helpers.copy_docstring(credentials.Credentials)
def refresh(self, request):
scopes = self._scopes if self._scopes is not None else self._default_scopes
# Use refresh handler if available and no refresh token is
# available. This is useful in general when tokens are obtained by calling
# some external process on demand. It is particularly useful for retrieving
# downscoped tokens from a token broker.
if self._refresh_token is None and self.refresh_handler:
token, expiry = self.refresh_handler(request, scopes=scopes)
# Validate returned data.
if not isinstance(token, six.string_types):
raise exceptions.RefreshError(
"The refresh_handler returned token is not a string."
)
if not isinstance(expiry, datetime):
raise exceptions.RefreshError(
"The refresh_handler returned expiry is not a datetime object."
)
if _helpers.utcnow() >= expiry - _helpers.REFRESH_THRESHOLD:
raise exceptions.RefreshError(
"The credentials returned by the refresh_handler are "
"already expired."
)
self.token = token
self.expiry = expiry
return
if (
self._refresh_token is None
or self._token_uri is None
or self._client_id is None
or self._client_secret is None
):
raise exceptions.RefreshError(
"The credentials do not contain the necessary fields need to "
"refresh the access token. You must specify refresh_token, "
"token_uri, client_id, and client_secret."
)
(
access_token,
refresh_token,
expiry,
grant_response,
rapt_token,
) = reauth.refresh_grant(
request,
self._token_uri,
self._refresh_token,
self._client_id,
self._client_secret,
scopes=scopes,
rapt_token=self._rapt_token,
enable_reauth_refresh=self._enable_reauth_refresh,
)
self.token = access_token
self.expiry = expiry
self._refresh_token = refresh_token
self._id_token = grant_response.get("id_token")
self._rapt_token = rapt_token
if scopes and "scope" in grant_response:
requested_scopes = frozenset(scopes)
granted_scopes = frozenset(grant_response["scope"].split())
scopes_requested_but_not_granted = requested_scopes - granted_scopes
if scopes_requested_but_not_granted:
raise exceptions.RefreshError(
"Not all requested scopes were granted by the "
"authorization server, missing scopes {}.".format(
", ".join(scopes_requested_but_not_granted)
)
)
[docs] @classmethod
def from_authorized_user_info(cls, info, scopes=None):
"""Creates a Credentials instance from parsed authorized user info.
Args:
info (Mapping[str, str]): The authorized user info in Google
format.
scopes (Sequence[str]): Optional list of scopes to include in the
credentials.
Returns:
google.oauth2.credentials.Credentials: The constructed
credentials.
Raises:
ValueError: If the info is not in the expected format.
"""
keys_needed = set(("refresh_token", "client_id", "client_secret"))
missing = keys_needed.difference(six.iterkeys(info))
if missing:
raise ValueError(
"Authorized user info was not in the expected format, missing "
"fields {}.".format(", ".join(missing))
)
# access token expiry (datetime obj); auto-expire if not saved
expiry = info.get("expiry")
if expiry:
expiry = datetime.strptime(
expiry.rstrip("Z").split(".")[0], "%Y-%m-%dT%H:%M:%S"
)
else:
expiry = _helpers.utcnow() - _helpers.REFRESH_THRESHOLD
# process scopes, which needs to be a seq
if scopes is None and "scopes" in info:
scopes = info.get("scopes")
if isinstance(scopes, six.string_types):
scopes = scopes.split(" ")
return cls(
token=info.get("token"),
refresh_token=info.get("refresh_token"),
token_uri=_GOOGLE_OAUTH2_TOKEN_ENDPOINT, # always overrides
scopes=scopes,
client_id=info.get("client_id"),
client_secret=info.get("client_secret"),
quota_project_id=info.get("quota_project_id"), # may not exist
expiry=expiry,
rapt_token=info.get("rapt_token"), # may not exist
)
[docs] @classmethod
def from_authorized_user_file(cls, filename, scopes=None):
"""Creates a Credentials instance from an authorized user json file.
Args:
filename (str): The path to the authorized user json file.
scopes (Sequence[str]): Optional list of scopes to include in the
credentials.
Returns:
google.oauth2.credentials.Credentials: The constructed
credentials.
Raises:
ValueError: If the file is not in the expected format.
"""
with io.open(filename, "r", encoding="utf-8") as json_file:
data = json.load(json_file)
return cls.from_authorized_user_info(data, scopes)
[docs] def to_json(self, strip=None):
"""Utility function that creates a JSON representation of a Credentials
object.
Args:
strip (Sequence[str]): Optional list of members to exclude from the
generated JSON.
Returns:
str: A JSON representation of this instance. When converted into
a dictionary, it can be passed to from_authorized_user_info()
to create a new credential instance.
"""
prep = {
"token": self.token,
"refresh_token": self.refresh_token,
"token_uri": self.token_uri,
"client_id": self.client_id,
"client_secret": self.client_secret,
"scopes": self.scopes,
"rapt_token": self.rapt_token,
}
if self.expiry: # flatten expiry timestamp
prep["expiry"] = self.expiry.isoformat() + "Z"
# Remove empty entries (those which are None)
prep = {k: v for k, v in prep.items() if v is not None}
# Remove entries that explicitely need to be removed
if strip is not None:
prep = {k: v for k, v in prep.items() if k not in strip}
return json.dumps(prep)
[docs]class UserAccessTokenCredentials(credentials.CredentialsWithQuotaProject):
"""Access token credentials for user account.
Obtain the access token for a given user account or the current active
user account with the ``gcloud auth print-access-token`` command.
Args:
account (Optional[str]): Account to get the access token for. If not
specified, the current active account will be used.
quota_project_id (Optional[str]): The project ID used for quota
and billing.
"""
def __init__(self, account=None, quota_project_id=None):
super(UserAccessTokenCredentials, self).__init__()
self._account = account
self._quota_project_id = quota_project_id
[docs] def with_account(self, account):
"""Create a new instance with the given account.
Args:
account (str): Account to get the access token for.
Returns:
google.oauth2.credentials.UserAccessTokenCredentials: The created
credentials with the given account.
"""
return self.__class__(account=account, quota_project_id=self._quota_project_id)
[docs] @_helpers.copy_docstring(credentials.CredentialsWithQuotaProject)
def with_quota_project(self, quota_project_id):
return self.__class__(account=self._account, quota_project_id=quota_project_id)
[docs] def refresh(self, request):
"""Refreshes the access token.
Args:
request (google.auth.transport.Request): This argument is required
by the base class interface but not used in this implementation,
so just set it to `None`.
Raises:
google.auth.exceptions.UserAccessTokenError: If the access token
refresh failed.
"""
self.token = _cloud_sdk.get_auth_access_token(self._account)
[docs] @_helpers.copy_docstring(credentials.Credentials)
def before_request(self, request, method, url, headers):
self.refresh(request)
self.apply(headers)
