Replace custom blob gRPC API with ByteStream

client/third_party/google/oauth2/id_token.py

+# 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.
+
+"""Google ID Token helpers."""
+
+import json
+
+from six.moves import http_client
+
+from google.auth import exceptions
+from google.auth import jwt
+
+# The URL that provides public certificates for verifying ID tokens issued
+# by Google's OAuth 2.0 authorization server.
+_GOOGLE_OAUTH2_CERTS_URL = 'https://www.googleapis.com/oauth2/v1/certs'
+
+# The URL that provides public certificates for verifying ID tokens issued
+# by Firebase and the Google APIs infrastructure
+_GOOGLE_APIS_CERTS_URL = (
+    'https://www.googleapis.com/robot/v1/metadata/x509'
+    '/securetoken@system.gserviceaccount.com')
+
+
+def _fetch_certs(request, certs_url):
+    """Fetches certificates.
+
+    Google-style cerificate endpoints return JSON in the format of
+    ``{'key id': 'x509 certificate'}``.
+
+    Args:
+        request (google.auth.transport.Request): The object used to make
+            HTTP requests.
+        certs_url (str): The certificate endpoint URL.
+
+    Returns:
+        Mapping[str, str]: A mapping of public key ID to x.509 certificate
+            data.
+    """
+    response = request(certs_url, method='GET')
+
+    if response.status != http_client.OK:
+        raise exceptions.TransportError(
+            'Could not fetch certificates at {}'.format(certs_url))
+
+    return json.loads(response.data.decode('utf-8'))
+
+
+def verify_token(id_token, request, audience=None,
+                 certs_url=_GOOGLE_OAUTH2_CERTS_URL):
+    """Verifies an ID token and returns the decoded token.
+
+    Args:
+        id_token (Union[str, bytes]): The encoded token.
+        request (google.auth.transport.Request): The object used to make
+            HTTP requests.
+        audience (str): The audience that this token is intended for. If None
+            then the audience is not verified.
+        certs_url (str): The URL that specifies the certificates to use to
+            verify the token. This URL should return JSON in the format of
+            ``{'key id': 'x509 certificate'}``.
+
+    Returns:
+        Mapping[str, Any]: The decoded token.
+    """
+    certs = _fetch_certs(request, certs_url)
+
+    return jwt.decode(id_token, certs=certs, audience=audience)
+
+
+def verify_oauth2_token(id_token, request, audience=None):
+    """Verifies an ID Token issued by Google's OAuth 2.0 authorization server.
+
+    Args:
+        id_token (Union[str, bytes]): The encoded token.
+        request (google.auth.transport.Request): The object used to make
+            HTTP requests.
+        audience (str): The audience that this token is intended for. This is
+            typically your application's OAuth 2.0 client ID. If None then the
+            audience is not verified.
+
+    Returns:
+        Mapping[str, Any]: The decoded token.
+    """
+    return verify_token(
+        id_token, request, audience=audience,
+        certs_url=_GOOGLE_OAUTH2_CERTS_URL)
+
+
+def verify_firebase_token(id_token, request, audience=None):
+    """Verifies an ID Token issued by Firebase Authentication.
+
+    Args:
+        id_token (Union[str, bytes]): The encoded token.
+        request (google.auth.transport.Request): The object used to make
+            HTTP requests.
+        audience (str): The audience that this token is intended for. This is
+            typically your Firebase application ID. If None then the audience
+            is not verified.
+
+    Returns:
+        Mapping[str, Any]: The decoded token.
+    """
+    return verify_token(
+        id_token, request, audience=audience, certs_url=_GOOGLE_APIS_CERTS_URL)