auth: implement OAuth2 flow.oauth2_auth_flow

Add code to implement the OAuth2 flow.

* Add test fixtures for setting up users and OAuth2 clients
* Add tests for token generation with the "Password Grant" flow
* Fix some issues with test due to changes in the database connection's
  row_factory

1 files changed, 30 insertions, 0 deletions

diff --git a/gn3/auth/authentication/oauth2/endpoints/utilities.py b/gn3/auth/authentication/oauth2/endpoints/utilities.py
new file mode 100644
index 0000000..299f151
--- /dev/null
+++ b/gn3/auth/authentication/oauth2/endpoints/utilities.py
@@ -0,0 +1,30 @@
+"""endpoint utilities"""
+from typing import Any, Optional
+
+from flask import current_app
+from pymonad.maybe import Nothing
+
+from gn3.auth import db
+from gn3.auth.authentication.oauth2.models.oauth2token import (
+    OAuth2Token, token_by_access_token, token_by_refresh_token)
+
+def query_token(# pylint: disable=[unused-argument]
+        endpoint_object: Any, token_str: str, token_type_hint) -> Optional[
+            OAuth2Token]:
+    """Retrieve the token from the database."""
+    __identity__ = lambda val: val
+    token = Nothing
+    with db.connection(current_app.config["AUTH_DB"]) as conn:
+        if token_type_hint == "access_token":
+            token = token_by_access_token(conn, token_str)
+        if token_type_hint == "access_token":
+            token = token_by_refresh_token(conn, token_str)
+
+        return token.maybe(
+            token_by_access_token(conn, token_str).maybe(
+                token_by_refresh_token(conn, token_str).maybe(
+                    None, __identity__),
+                __identity__),
+            __identity__)
+
+    return None