Django 清除特定视图缓存

缺乏、安全感 2023-06-12 04:14 12阅读 0赞

## Django 清除特定视图缓存 ##

**Django 只提供了清楚所有缓存的入口，而未提供清楚某个特定视图缓存的入口。由于需求需要，笔者研究Django缓存机制，找到了清除特定视图缓存的方法。**

### 记录如下（以下代码均是按照Django源码所写）： ###

#### 构造构造缓存的键，供查找缓存 ####

def get_cache_key(request, url, cache, key_prefix=None):
        """
        构造缓存的键，供查找缓存
        :param request:
        :param url:完整路由
        :param key_prefix:如果设置，则按照设置，如果未设置，则按照默认
        :param cache:
        :return: 视图内容缓存，视图请求头缓存
        """
        if key_prefix is None:
            key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
        url = hashlib.md5(force_bytes(iri_to_uri(url)))
        cache_key = 'views.decorators.cache.cache_header.%s.%s' % (
            key_prefix, url.hexdigest())
        cache_key_header = _i18n_cache_key_suffix(request, cache_key)
    
        headerlist = cache.get(cache_key_header)
        if headerlist is not None:
            ctx = hashlib.md5()
            for header in headerlist:
                value = request.META.get(header)
                if value is not None:
                    ctx.update(force_bytes(value))
            cache_key = 'views.decorators.cache.cache_page.%s.%s.%s.%s' % (
                key_prefix, 'GET', url.hexdigest(), ctx.hexdigest())
            return _i18n_cache_key_suffix(request, cache_key), cache_key_header
        else:
            return None, None

#### 用于删除缓存的视图 ####

from django.conf import settings
    from django.core.cache import caches
    from the_van.utils.utils import  get_cache_key
    
    class SomeViewSet(ModelViewSet):
        queryset = Some.objects.all()
        serializer_class = SomeSerializer
    
        @action(detail=False, methods=['get'])
        def clear(self, request):
        	# 要清理缓存的路由
            url = request.query_params.get('url', None)
            if url is None:
                return JsonResponse({'message': '请传入参数', 'status': 404, 'data': {}})
            cache_alias = settings.CACHE_MIDDLEWARE_ALIAS
            key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
            cache = caches[cache_alias]
            url = request.META['wsgi.url_scheme'] + '://' + request.META['HTTP_HOST'] + '/' + 'video/'
            cache_key, cache_key_header = get_cache_key(request, url, cache, key_prefix=key_prefix)
            if cache_key is None:
                return JsonResponse({'message': '没有对应缓存', 'status': 200, 'data': {}})
            cache.delete(cache_key)
            cache.delete(cache_key_header)
            return JsonResponse({'message': '清除缓存成功', 'status': 200, 'data': {}})