[英]How to create a mixin pattern in Python
我正在尝试使用以下示例理解mixins的概念:
我有一个使用DRF的简单序列化器:
class TestSerializer(serializers.ModelSerializer):
class Meta:
model = Test
fields = ('url', 'name', 'user')
我想创建一个mixin,它通过添加检查用户拥有对象并仅显示这些项目的方式,来增强(覆盖类get_queryset类)任何自定义序列化程序...
def get_queryset(self):
"""
This view should return a list of all the items
for the currently authenticated user.
"""
user = self.request.user
return ???????.objects.filter(user=user)
所以我的TestSerializer看起来像这样:
class TestSerializer(serializers.ModelSerializer, UserListMixin):
etc
和UserListMixin:
class UserListMixin(object):
"""
Filtering based on the value of request.user.
"""
def get_queryset(self, *args, **kwargs):
"""
This view should return a list of all the purchases
for the currently authenticated user.
"""
user = self.request.user
return super([?????????], self).get_queryset(*args, **kwargs).filter(user=user)
我遇到的困难是创建UserListMixin
类。 如何根据扩展的内容return [OBJECT].objects.filter(user=user)
正确的对象return [OBJECT].objects.filter(user=user)
,这种方法行得通吗?
过滤器是可链接的,因此这里最好的做法是调用super方法以获取默认查询集,然后在顶部添加过滤器:
def get_queryset(self, *args, **kwargs)
user = self.request.user
return super(UserListMixin, self).get_queryset(*args, **kwargs).filter(user=user)
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