# Copyright 2020 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 async client. This is a client for interacting with an OAuth 2.0 authorization server's token endpoint. For more information about the token endpoint, see `Section 3.1 of rfc6749`_ .. _Section 3.1 of rfc6749: https://tools.ietf.org/html/rfc6749#section-3.2 """ import datetime import json import six from six.moves import http_client from six.moves import urllib from google.auth import _helpers from google.auth import exceptions from google.auth import jwt from google.oauth2 import _client as client def _handle_error_response(response_body): """"Translates an error response into an exception. Args: response_body (str): The decoded response data. Raises: google.auth.exceptions.RefreshError """ try: error_data = json.loads(response_body) error_details = "{}: {}".format( error_data["error"], error_data.get("error_description") ) # If no details could be extracted, use the response data. except (KeyError, ValueError): error_details = response_body raise exceptions.RefreshError(error_details, response_body) def _parse_expiry(response_data): """Parses the expiry field from a response into a datetime. Args: response_data (Mapping): The JSON-parsed response data. Returns: Optional[datetime]: The expiration or ``None`` if no expiration was specified. """ expires_in = response_data.get("expires_in", None) if expires_in is not None: return _helpers.utcnow() + datetime.timedelta(seconds=expires_in) else: return None async def _token_endpoint_request(request, token_uri, body): """Makes a request to the OAuth 2.0 authorization server's token endpoint. Args: request (google.auth.transport.Request): A callable used to make HTTP requests. token_uri (str): The OAuth 2.0 authorizations server's token endpoint URI. body (Mapping[str, str]): The parameters to send in the request body. Returns: Mapping[str, str]: The JSON-decoded response data. Raises: google.auth.exceptions.RefreshError: If the token endpoint returned an error. """ body = urllib.parse.urlencode(body).encode("utf-8") headers = {"content-type": client._URLENCODED_CONTENT_TYPE} retry = 0 # retry to fetch token for maximum of two times if any internal failure # occurs. while True: response = await request( method="POST", url=token_uri, headers=headers, body=body ) # Using data.read() resulted in zlib decompression errors. This may require future investigation. response_body1 = await response.content() response_body = ( response_body1.decode("utf-8") if hasattr(response_body1, "decode") else response_body1 ) response_data = json.loads(response_body) if response.status == http_client.OK: break else: error_desc = response_data.get("error_description") or "" error_code = response_data.get("error") or "" if ( any(e == "internal_failure" for e in (error_code, error_desc)) and retry < 1 ): retry += 1 continue _handle_error_response(response_body) return response_data async def jwt_grant(request, token_uri, assertion): """Implements the JWT Profile for OAuth 2.0 Authorization Grants. For more details, see `rfc7523 section 4`_. Args: request (google.auth.transport.Request): A callable used to make HTTP requests. token_uri (str): The OAuth 2.0 authorizations server's token endpoint URI. assertion (str): The OAuth 2.0 assertion. Returns: Tuple[str, Optional[datetime], Mapping[str, str]]: The access token, expiration, and additional data returned by the token endpoint. Raises: google.auth.exceptions.RefreshError: If the token endpoint returned an error. .. _rfc7523 section 4: https://tools.ietf.org/html/rfc7523#section-4 """ body = {"assertion": assertion, "grant_type": client._JWT_GRANT_TYPE} response_data = await _token_endpoint_request(request, token_uri, body) try: access_token = response_data["access_token"] except KeyError as caught_exc: new_exc = exceptions.RefreshError("No access token in response.", response_data) six.raise_from(new_exc, caught_exc) expiry = _parse_expiry(response_data) return access_token, expiry, response_data async def id_token_jwt_grant(request, token_uri, assertion): """Implements the JWT Profile for OAuth 2.0 Authorization Grants, but requests an OpenID Connect ID Token instead of an access token. This is a variant on the standard JWT Profile that is currently unique to Google. This was added for the benefit of authenticating to services that require ID Tokens instead of access tokens or JWT bearer tokens. Args: request (google.auth.transport.Request): A callable used to make HTTP requests. token_uri (str): The OAuth 2.0 authorization server's token endpoint URI. assertion (str): JWT token signed by a service account. The token's payload must include a ``target_audience`` claim. Returns: Tuple[str, Optional[datetime], Mapping[str, str]]: The (encoded) Open ID Connect ID Token, expiration, and additional data returned by the endpoint. Raises: google.auth.exceptions.RefreshError: If the token endpoint returned an error. """ body = {"assertion": assertion, "grant_type": client._JWT_GRANT_TYPE} response_data = await _token_endpoint_request(request, token_uri, body) try: id_token = response_data["id_token"] except KeyError as caught_exc: new_exc = exceptions.RefreshError("No ID token in response.", response_data) six.raise_from(new_exc, caught_exc) payload = jwt.decode(id_token, verify=False) expiry = datetime.datetime.utcfromtimestamp(payload["exp"]) return id_token, expiry, response_data async def refresh_grant( request, token_uri, refresh_token, client_id, client_secret, scopes=None ): """Implements the OAuth 2.0 refresh token grant. For more details, see `rfc678 section 6`_. Args: request (google.auth.transport.Request): A callable used to make HTTP requests. token_uri (str): The OAuth 2.0 authorizations server's token endpoint URI. refresh_token (str): The refresh token to use to get a new access token. client_id (str): The OAuth 2.0 application's client ID. client_secret (str): The Oauth 2.0 appliaction's client secret. scopes (Optional(Sequence[str])): Scopes to request. If present, all scopes must be authorized for the refresh token. Useful if refresh token has a wild card scope (e.g. 'https://www.googleapis.com/auth/any-api'). Returns: Tuple[str, Optional[str], Optional[datetime], Mapping[str, str]]: The access token, new refresh token, expiration, and additional data returned by the token endpoint. Raises: google.auth.exceptions.RefreshError: If the token endpoint returned an error. .. _rfc6748 section 6: https://tools.ietf.org/html/rfc6749#section-6 """ body = { "grant_type": client._REFRESH_GRANT_TYPE, "client_id": client_id, "client_secret": client_secret, "refresh_token": refresh_token, } if scopes: body["scope"] = " ".join(scopes) response_data = await _token_endpoint_request(request, token_uri, body) try: access_token = response_data["access_token"] except KeyError as caught_exc: new_exc = exceptions.RefreshError("No access token in response.", response_data) six.raise_from(new_exc, caught_exc) refresh_token = response_data.get("refresh_token", refresh_token) expiry = _parse_expiry(response_data) return access_token, refresh_token, expiry, response_data