25.自定义mixin和基类

很多时候业务需求并不是几个简单的mixin就可以满足，需要我们自定义mixin

# get_object源码中字段查询源代码

    filter_kwargs = {self.lookup_field: self.kwargs[lookup_url_kwarg]}
    obj = get_object_or_404(queryset, **filter_kwargs)

 

# 自定义多字段查询mixin
class MultipleFieldLookupMixin(object):
    # 重写GenericAPIView里面的 get_object
    def get_object(self):
        queryset = self.get_queryset()
        queryset = self.filter_queryset(queryset)
        filter = {} # 重新字段部分代码，原来是只有一个字段，使用循环处理返回多个字段
        for field in self.lookup_fields:
            if self.kwargs[field]:
                filter[field] = self.kwargs[field]

        obj = get_object_or_404(queryset, **filter)
        self.check_object_permissions(self.request, obj)
        return obj

# 继承自定义多字段查询mixin class RetrievePostView(MultipleFieldLookupMixin,generics.RetrieveAPIView): queryset = Post.objects.all() serizlizer_calss = PostSerializer lookup_fields = ('pk','title') # 多字段

# 继承自定义多字段查询mixin
class RetrievePostView(MultipleFieldLookupMixin,generics.RetrieveAPIView):
    queryset = Post.objects.all()
    serizlizer_calss = PostSerializer
    lookup_fields = ('pk','title') # 多字段

#url视图匹配多个字段
path('posts/<int:pk>/<str:title>', RetrievePostView.as_view()),