Source code for google.oauth2.utils

# 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.
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"""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

    * 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:
.. _RFC 6749 section 5.2:

import abc
import base64
import enum
import json

from google.auth import exceptions

# OAuth client authentication based on
[docs] class ClientAuthType(enum.Enum): basic = 1 request_body = 2
[docs] class ClientAuthentication(object): """Defines the client authentication credentials for basic and request-body types based on """ 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
[docs] class OAuthClientAuthHandler(metaclass=abc.ABCMeta): """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
[docs] 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 "" )
[docs] 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)