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Diffstat (limited to 'google/oauth2/utils.py')
| -rw-r--r-- | google/oauth2/utils.py | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/google/oauth2/utils.py b/google/oauth2/utils.py new file mode 100644 index 0000000..593f032 --- /dev/null +++ b/google/oauth2/utils.py @@ -0,0 +1,171 @@ +# 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 Utilities. + +This module provides implementations for various OAuth 2.0 utilities. +This includes `OAuth error handling`_ and +`Client authentication for OAuth flows`_. + +OAuth error handling +-------------------- +This will define interfaces for handling OAuth related error responses as +stated in `RFC 6749 section 5.2`_. +This will include a common function to convert these HTTP error responses to a +:class:`google.auth.exceptions.OAuthError` exception. + + +Client authentication for OAuth flows +------------------------------------- +We introduce an interface for defining client authentication credentials based +on `RFC 6749 section 2.3.1`_. This will expose the following +capabilities: + + * Ability to support basic authentication via request header. + * Ability to support bearer token authentication via request header. + * Ability to support client ID / secret authentication via request body. + +.. _RFC 6749 section 2.3.1: https://tools.ietf.org/html/rfc6749#section-2.3.1 +.. _RFC 6749 section 5.2: https://tools.ietf.org/html/rfc6749#section-5.2 +""" + +import abc +import base64 +import enum +import json + +import six + +from google.auth import exceptions + + +# OAuth client authentication based on +# https://tools.ietf.org/html/rfc6749#section-2.3. +class ClientAuthType(enum.Enum): + basic = 1 + request_body = 2 + + +class ClientAuthentication(object): + """Defines the client authentication credentials for basic and request-body + types based on https://tools.ietf.org/html/rfc6749#section-2.3.1. + """ + + def __init__(self, client_auth_type, client_id, client_secret=None): + """Instantiates a client authentication object containing the client ID + and secret credentials for basic and response-body auth. + + Args: + client_auth_type (google.oauth2.oauth_utils.ClientAuthType): The + client authentication type. + client_id (str): The client ID. + client_secret (Optional[str]): The client secret. + """ + self.client_auth_type = client_auth_type + self.client_id = client_id + self.client_secret = client_secret + + +@six.add_metaclass(abc.ABCMeta) +class OAuthClientAuthHandler(object): + """Abstract class for handling client authentication in OAuth-based + operations. + """ + + def __init__(self, client_authentication=None): + """Instantiates an OAuth client authentication handler. + + Args: + client_authentication (Optional[google.oauth2.utils.ClientAuthentication]): + The OAuth client authentication credentials if available. + """ + super(OAuthClientAuthHandler, self).__init__() + self._client_authentication = client_authentication + + def apply_client_authentication_options( + self, headers, request_body=None, bearer_token=None + ): + """Applies client authentication on the OAuth request's headers or POST + body. + + Args: + headers (Mapping[str, str]): The HTTP request header. + request_body (Optional[Mapping[str, str]]): The HTTP request body + dictionary. For requests that do not support request body, this + is None and will be ignored. + bearer_token (Optional[str]): The optional bearer token. + """ + # Inject authenticated header. + self._inject_authenticated_headers(headers, bearer_token) + # Inject authenticated request body. + if bearer_token is None: + self._inject_authenticated_request_body(request_body) + + def _inject_authenticated_headers(self, headers, bearer_token=None): + if bearer_token is not None: + headers["Authorization"] = "Bearer %s" % bearer_token + elif ( + self._client_authentication is not None + and self._client_authentication.client_auth_type is ClientAuthType.basic + ): + username = self._client_authentication.client_id + password = self._client_authentication.client_secret or "" + + credentials = base64.b64encode( + ("%s:%s" % (username, password)).encode() + ).decode() + headers["Authorization"] = "Basic %s" % credentials + + def _inject_authenticated_request_body(self, request_body): + if ( + self._client_authentication is not None + and self._client_authentication.client_auth_type + is ClientAuthType.request_body + ): + if request_body is None: + raise exceptions.OAuthError( + "HTTP request does not support request-body" + ) + else: + request_body["client_id"] = self._client_authentication.client_id + request_body["client_secret"] = ( + self._client_authentication.client_secret or "" + ) + + +def handle_error_response(response_body): + """Translates an error response from an OAuth operation into an + OAuthError exception. + + Args: + response_body (str): The decoded response data. + + Raises: + google.auth.exceptions.OAuthError + """ + try: + error_components = [] + error_data = json.loads(response_body) + + error_components.append("Error code {}".format(error_data["error"])) + if "error_description" in error_data: + error_components.append(": {}".format(error_data["error_description"])) + if "error_uri" in error_data: + error_components.append(" - {}".format(error_data["error_uri"])) + error_details = "".join(error_components) + # If no details could be extracted, use the response data. + except (KeyError, ValueError): + error_details = response_body + + raise exceptions.OAuthError(error_details, response_body) |