Validate JWTs against all existing JWKs.

1 files changed, 35 insertions, 0 deletions

diff --git a/gn_auth/auth/authentication/oauth2/resource_server.py b/gn_auth/auth/authentication/oauth2/resource_server.py
index 2405ee2..6ebaecb 100644
--- a/gn_auth/auth/authentication/oauth2/resource_server.py
+++ b/gn_auth/auth/authentication/oauth2/resource_server.py
@@ -1,9 +1,14 @@
 """Protect the resources endpoints"""
+from datetime import datetime, timezone, timedelta
 
 from flask import current_app as app
+
+from authlib.jose import KeySet
+from authlib.oauth2.rfc7523 import JWTBearerTokenValidator as _JWTBearerTokenValidator
 from authlib.oauth2.rfc6750 import BearerTokenValidator as _BearerTokenValidator
 from authlib.integrations.flask_oauth2 import ResourceProtector
 
+from gn_auth.auth.jwks import list_jwks, jwks_directory
 from gn_auth.auth.db import sqlite3 as db
 from gn_auth.auth.authentication.oauth2.models.oauth2token import token_by_access_token
 
@@ -14,4 +19,34 @@ class BearerTokenValidator(_BearerTokenValidator):
             return token_by_access_token(conn, token_string).maybe(# type: ignore[misc]
                 None, lambda tok: tok)
 
+class JWTBearerTokenValidator(_JWTBearerTokenValidator):
+    """Validate a token using all the keys"""
+    _local_attributes = ("jwt_refresh_frequency_hours",)
+
+    def __init__(self, public_key, issuer=None, realm=None, **extra_attributes):
+        """Initialise the validator class."""
+        # https://docs.authlib.org/en/latest/jose/jwt.html#use-dynamic-keys
+        # We can simply use the KeySet rather than a specific key.
+        super().__init__(public_key,
+                         issuer,
+                         realm,
+                         **{
+                             key: value for key,value
+                             in extra_attributes.items()
+                             if key not in self._local_attributes
+                         })
+        self._last_jwks_update = datetime.now(tz=timezone.utc)
+        self._refresh_frequency = timedelta(hours=int(
+            extra_attributes.get("jwt_refresh_frequency_hours", 6)))
+
+    def __refresh_jwks__(self):
+        now = datetime.now(tz=timezone.utc)
+        if (now - self._last_jwks_update) >= self._refresh_frequency:
+            self.public_key = KeySet(list_jwks(jwks_directory(app)))
+
+    def authenticate_token(self, token_string: str):
+        self.__refresh_jwks__()
+        return super().authenticate_token(token_string)
+
+
 require_oauth = ResourceProtector()