将缓存基于Django类的视图响应与请求中的参数绑定

Question

我想缓存API响应，并将其与GET请求中存在的参数绑定。请求如下：

GET /products?producent=some_company

这是我的简化类：

class ProductsListCreate(generics.ListCreateAPIView):
def list(self, request, *args, **kwargs):
producent = request.query_params.get("producent")
cached_response = cache.get(f"response-products-{producent}", None)
if not cached_response:
queryset = self.filter_queryset(self.get_queryset())
page = self.paginate_queryset(queryset)
serializer = self.get_serializer(page)
response = self.get_paginated_response(serializer.data)
cache.set(f"response-products-{producent}", response , timeout=20)
return response
return cached_response 

但当我试图缓存响应时，我收到错误：

django.template.response.ContentNotRenderedError: The response content must be rendered before it can be pickled.

你有什么建议吗？我在这里搜索https://docs.djangoproject.com/en/3.2/topics/cache/当我想弄清楚的时候。起初，我尝试了@cache_page的方法，但它不允许我使用请求中的参数，所以我想应该使用低级缓存API。

Answer 1

错误消息实际上很有描述性。在尝试将响应pickle为可缓存格式之前，必须对其调用render()。问题是：这将导致你陷入一个兔子洞，解构响应并从缓存的数据中重建。IMO，最好缓存查询集。然而，这就是它的样子：

class ProductsListCreate(generics.ListCreateAPIView):
def list(self, request, *args, **kwargs):
producent = request.query_params.get("producent")
response_triple = cache.get(f"response-products-{producent}", None)
if not response_triple:
queryset = self.filter_queryset(self.get_queryset())
page = self.paginate_queryset(queryset)
serializer = self.get_serializer(page)
response = self.get_paginated_response(serializer.data)
response.render()
if not response.status_code >= 400:
# django 3.0 has no .items() method, django 3.2 has no ._headers
if hasattr(response, '_headers'):
headers = response._headers.copy()
else:
headers = {k: (k, v) for k, v in response.items()}
response_triple = (
response.rendered_content,
response.status_code,
headers
)
cache.set(f"response-products-{producent}", response_triple, timeout=20)
else:
# build smaller Django HttpResponse
content, status, headers = response_triple
response = HttpResponse(content=content, status=status)
for k, v in headers.values():
response[k] = v
if not hasattr(response, '_closable_objects'):
response._closable_objects = []
return response

取自：https://github.com/chibisov/drf-extensions/blob/ecdf3a95d7f18ccf9cffa55809635c3715179605/rest_framework_extensions/cache/decorators.py#L63