From 6f998d49ddb4418e699564d83bcc834ad82b1098 Mon Sep 17 00:00:00 2001
From: Moritz Ulmer <moritz.ulmer@posteo.de>
Date: Fri, 3 Jun 2022 20:55:58 +0200
Subject: [PATCH] Speed up JWT decoding

Why:

- Almost 10x speed increase
- Total response 20% less time

This change addresses the need by:

- Adding TTL LRU cache to the decode function
---
 django_keycloak/keycloak.py | 2 ++
 setup.cfg                   | 1 +
 2 files changed, 3 insertions(+)

diff --git a/django_keycloak/keycloak.py b/django_keycloak/keycloak.py
index 6359c3b..7995406 100644
--- a/django_keycloak/keycloak.py
+++ b/django_keycloak/keycloak.py
@@ -8,6 +8,7 @@
 from django.conf import settings
 from jwt import PyJWKClient
 from jwt.exceptions import InvalidTokenError
+from cachetools.func import ttl_cache
 
 from .decorators import keycloak_api_error_handler
 from .urls import (
@@ -399,6 +400,7 @@ def _make_request_config(self):
             headers["HOST"] = urlparse(self.internal_url).netloc
         return [server_url, headers]
 
+    @ttl_cache(maxsize=128, ttl=60)
     def _decode_token(
         self, token: str, audience: Union[str, List[str]], raise_error=False
     ) -> Optional[Dict]:
diff --git a/setup.cfg b/setup.cfg
index e5e08d4..4f522ad 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -23,4 +23,5 @@ install_requires =
     dry-rest-permissions >= "0.1"
     jwt >= "1.0"
     requests >= "2.0"
+    cachetools >= "5.0"