feat: add reauth support to async user credentials (#738)

google/oauth2/_client_async.py

@@ -30,70 +30,40 @@
 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):
+async def _token_endpoint_request_no_throw(
+    request, token_uri, body, access_token=None, use_json=False
+):
     """Makes a request to the OAuth 2.0 authorization server's token endpoint.
+    This function doesn't throw on response errors.
 
     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.
+        access_token (Optional(str)): The access token needed to make the request.
+        use_json (Optional(bool)): Use urlencoded format or json format for the
+            content type. The default value is False.
 
     Returns:
-        Mapping[str, str]: The JSON-decoded response data.
-
-    Raises:
-        google.auth.exceptions.RefreshError: If the token endpoint returned
-            an error.
+        Tuple(bool, Mapping[str, str]): A boolean indicating if the request is
+            successful, and a mapping for the JSON-decoded response data.
     """
-    body = urllib.parse.urlencode(body).encode("utf-8")
-    headers = {"content-type": client._URLENCODED_CONTENT_TYPE}
+    if use_json:
+        headers = {"Content-Type": client._JSON_CONTENT_TYPE}
+        body = json.dumps(body).encode("utf-8")
+    else:
+        headers = {"Content-Type": client._URLENCODED_CONTENT_TYPE}
+        body = urllib.parse.urlencode(body).encode("utf-8")
+
+    if access_token:
+        headers["Authorization"] = "Bearer {}".format(access_token)
 
     retry = 0
     # retry to fetch token for maximum of two times if any internal failure
@@ -126,8 +96,38 @@ async def _token_endpoint_request(request, token_uri, body):
             ):
                 retry += 1
                 continue
-            _handle_error_response(response_body)
+            return response.status == http_client.OK, response_data
 
+    return response.status == http_client.OK, response_data
+
+
+async def _token_endpoint_request(
+    request, token_uri, body, access_token=None, use_json=False
+):
+    """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.
+        access_token (Optional(str)): The access token needed to make the request.
+        use_json (Optional(bool)): Use urlencoded format or json format for the
+            content type. The default value is False.
+
+    Returns:
+        Mapping[str, str]: The JSON-decoded response data.
+
+    Raises:
+        google.auth.exceptions.RefreshError: If the token endpoint returned
+            an error.
+    """
+    response_status_ok, response_data = await _token_endpoint_request_no_throw(
+        request, token_uri, body, access_token=access_token, use_json=use_json
+    )
+    if not response_status_ok:
+        client._handle_error_response(response_data)
     return response_data
 
 
@@ -163,7 +163,7 @@ async def jwt_grant(request, token_uri, assertion):
         new_exc = exceptions.RefreshError("No access token in response.", response_data)
         six.raise_from(new_exc, caught_exc)
 
-    expiry = _parse_expiry(response_data)
+    expiry = client._parse_expiry(response_data)
 
     return access_token, expiry, response_data
 
@@ -210,7 +210,13 @@ async def id_token_jwt_grant(request, token_uri, assertion):
 
 
 async def refresh_grant(
-    request, token_uri, refresh_token, client_id, client_secret, scopes=None
+    request,
+    token_uri,
+    refresh_token,
+    client_id,
+    client_secret,
+    scopes=None,
+    rapt_token=None,
 ):
     """Implements the OAuth 2.0 refresh token grant.
 
@@ -229,10 +235,11 @@ async def refresh_grant(
             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').
+        rapt_token (Optional(str)): The reauth Proof Token.
 
     Returns:
         Tuple[str, Optional[str], Optional[datetime], Mapping[str, str]]: The
-            access token, new refresh token, expiration, and additional data
+            access token, new or current refresh token, expiration, and additional data
             returned by the token endpoint.
 
     Raises:
@@ -249,16 +256,8 @@ async def refresh_grant(
     }
     if scopes:
         body["scope"] = " ".join(scopes)
+    if rapt_token:
+        body["rapt"] = rapt_token
 
     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
+    return client._handle_refresh_grant_response(response_data, refresh_token)

google/oauth2/_credentials_async.py

@@ -34,7 +34,7 @@
 from google.auth import _credentials_async as credentials
 from google.auth import _helpers
 from google.auth import exceptions
-from google.oauth2 import _client_async as _client
+from google.oauth2 import _reauth_async as reauth
 from google.oauth2 import credentials as oauth2_credentials
 
 
@@ -66,23 +66,26 @@ async def refresh(self, request):
             refresh_token,
             expiry,
             grant_response,
-        ) = await _client.refresh_grant(
+            rapt_token,
+        ) = await reauth.refresh_grant(
             request,
             self._token_uri,
             self._refresh_token,
             self._client_id,
             self._client_secret,
-            self._scopes,
+            scopes=self._scopes,
+            rapt_token=self._rapt_token,
         )
 
         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 self._scopes and "scopes" in grant_response:
+        if self._scopes and "scope" in grant_response:
             requested_scopes = frozenset(self._scopes)
-            granted_scopes = frozenset(grant_response["scopes"].split())
+            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(