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

4 files changed, 99 insertions, 0 deletions

diff --git a/gn3/auth/authentication/oauth2/endpoints/__init__.py b/gn3/auth/authentication/oauth2/endpoints/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/gn3/auth/authentication/oauth2/endpoints/__init__.py
diff --git a/gn3/auth/authentication/oauth2/endpoints/introspection.py b/gn3/auth/authentication/oauth2/endpoints/introspection.py
new file mode 100644
index 0000000..a567363
--- /dev/null
+++ b/gn3/auth/authentication/oauth2/endpoints/introspection.py
@@ -0,0 +1,48 @@
+"""Handle introspection of tokens."""
+import datetime
+from urllib.parse import urlparse
+
+from flask import request as flask_request
+from authlib.oauth2.rfc7662 import (
+    IntrospectionEndpoint as _IntrospectionEndpoint)
+
+from gn3.auth.authentication.oauth2.models.oauth2token import OAuth2Token
+
+from .utilities import query_token as _query_token
+
+def get_token_user_sub(token: OAuth2Token) -> str:# pylint: disable=[unused-argument]
+    """
+    Return the token's subject as defined in
+    https://datatracker.ietf.org/doc/html/rfc7519#section-4.1.2
+    """
+    ## For now a dummy return to prevent issues.
+    return "sub"
+
+class IntrospectionEndpoint(_IntrospectionEndpoint):
+    """Introspect token."""
+    def query_token(self, token_string: str, token_type_hint: str):
+        """Query the token."""
+        return _query_token(self, token_string, token_type_hint)
+
+    def introspect_token(self, token: OAuth2Token) -> dict:# pylint: disable=[no-self-use]
+        """Return the introspection information."""
+        url = urlparse(flask_request.url)
+        return {
+            "active": True,
+            "scope": token.get_scope(),
+            "client_id": token.client.client_id,
+            "username": token.user.name,
+            "token_type": token.token_type,
+            "exp": int(token.expires_at.timestamp()),
+            "iat": int(token.issued_at.timestamp()),
+            "nbf": int(
+                (token.issued_at - datetime.timedelta(seconds=120)).timestamp()),
+            # "sub": get_token_user_sub(token),
+            "aud": token.client.client_id,
+            "iss": f"{url.scheme}://{url.netloc}",
+            "jti": token.token_id
+        }
+
+    def check_permission(self, token, client, request):# pylint: disable=[unused-argument, no-self-use]
+        """Check that the client has permission to introspect token."""
+        return client.client_type == "internal"
diff --git a/gn3/auth/authentication/oauth2/endpoints/revocation.py b/gn3/auth/authentication/oauth2/endpoints/revocation.py
new file mode 100644
index 0000000..0693c2d
--- /dev/null
+++ b/gn3/auth/authentication/oauth2/endpoints/revocation.py
@@ -0,0 +1,21 @@
+"""Handle token revocation."""
+
+from flask import current_app
+from authlib.oauth2.rfc7009 import RevocationEndpoint as _RevocationEndpoint
+
+from gn3.auth import db
+from gn3.auth.authentication.oauth2.models.oauth2token import (
+    save_token, OAuth2Token, revoke_token)
+
+from .utilities import query_token as _query_token
+
+class RevocationEndpoint(_RevocationEndpoint):
+    """Revoke the tokens"""
+    def query_token(self, token_string: str, token_type_hint: str):
+        """Query the token."""
+        return _query_token(self, token_string, token_type_hint)
+
+    def revoke_token(self, token: OAuth2Token, request):
+        """Revoke token `token`."""
+        with db.connection(current_app.config["AUTH_DB"]) as conn:
+            save_token(conn, revoke_token(token))
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