perf: 优化middleware的使用 (#4707)

perf: 优化middleware的使用

apps/authentication/backends/cas/middleware.py

@@ -0,0 +1,10 @@
+from django_cas_ng.middleware import CASMiddleware as _CASMiddleware
+from django.core.exceptions import MiddlewareNotUsed
+from django.conf import settings
+
+
+class CASMiddleware(_CASMiddleware):
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        if not settings.AUTH_CAS:
+            raise MiddlewareNotUsed