refactor(cache): use exception short-circuit in viewsets

apps/utils/viewsets.py

@@ -23,6 +23,13 @@ from django.db import connection
 from django.core.exceptions import ObjectDoesNotExist
 from django.db.utils import NotSupportedError
 
+
+class CachedResponseHit(Exception):
+    def __init__(self, data):
+        super().__init__('cached response hit')
+        self.data = data
+
+
 class CustomGenericViewSet(MyLoggingMixin, GenericViewSet):
     """
     增强的GenericViewSet
@@ -64,35 +71,11 @@ class CustomGenericViewSet(MyLoggingMixin, GenericViewSet):
         return super().__new__(cls)
     
     def finalize_response(self, request, response, *args, **kwargs):
-        if self.hash_k and self.cache_seconds:
+        if self.hash_k and self.cache_seconds and not getattr(self, '_from_cache', False):
             cache.set(self.hash_k, response.data,
                       timeout=self.cache_seconds)  # 将结果存入缓存，设置超时时间
         return super().finalize_response(request, response, *args, **kwargs)
 
-    def dispatch(self, request, *args, **kwargs):
-        self.args = args
-        self.kwargs = kwargs
-        request = self.initialize_request(request, *args, **kwargs)
-        self.request = request
-        self.headers = self.default_response_headers
-
-        try:
-            self.initial(request, *args, **kwargs)
-
-            if hasattr(self, '_cached_response'):
-                response = self._cached_response
-            else:
-                if request.method.lower() in self.http_method_names:
-                    handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
-                else:
-                    handler = self.http_method_not_allowed
-                response = handler(request, *args, **kwargs)
-        except Exception as exc:
-            response = self.handle_exception(exc)
-
-        self.response = self.finalize_response(request, response, *args, **kwargs)
-        return self.response
-
     def _normalize_cache_value(self, value):
         if hasattr(value, 'lists'):
             return {k: v if len(v) > 1 else v[0] for k, v in value.lists()}
@@ -114,6 +97,7 @@ class CustomGenericViewSet(MyLoggingMixin, GenericViewSet):
         return hashlib.sha256(payload_str.encode('utf-8')).hexdigest()
 
     def initial(self, request, *args, **kwargs):
+        self._from_cache = False
         super().initial(request, *args, **kwargs)
         cache_seconds = getattr(
             self, f"{self.action}_cache_seconds", getattr(self, 'cache_seconds', 0))
@@ -126,7 +110,13 @@ class CustomGenericViewSet(MyLoggingMixin, GenericViewSet):
             elif hash_v_e == self.cache_processing_flag:  # 说明请求正在处理
                 raise ParseError(f'请求忽略,请{self.cache_seconds}秒后重试')
             elif hash_v_e:
-                self._cached_response = Response(hash_v_e)
+                raise CachedResponseHit(hash_v_e)
+
+    def handle_exception(self, exc):
+        if isinstance(exc, CachedResponseHit):
+            self._from_cache = True
+            return Response(exc.data)
+        return super().handle_exception(exc)
 
     def get_object(self, force_lock=False):
         """