如何在Django中以正確的方式使用get_queryset？

Question

我正嘗試使用django的def_queryset爲django-rest-framework視圖編寫過濾器。我有一個列表視圖，我希望能夠使用4個不同的字段進行過濾 - 分別或同時進行。這是15種不同的組合（4個單元素，6個雙元素，4個三元素和1個四元素）。有可能是寫的，而不是大else語句，如下面的一個更聰明的辦法：

def get_queryset(self): 
    queryset = Comment.objects.filter(status=1) 
    post = self.request.QUERY_PARAMS.get('post', None) 
    parent = self.request.QUERY_PARAMS.get('parent', None) 
    author = self.request.QUERY_PARAMS.get('author', None) 
    email = self.request.QUERY_PARAMS.get('author', None) 

    # this is obviously incomplete 

    if post is not None and parent is not None and author is not None and email is not None: 
     queryset = queryset.filter(post=post, parent=parent, author=author, email=email) 
    elif post is not None and parent is not None and author is not None: 
     queryset = queryset.filter(post=post, parent=parent, author=author) 
    elif post is not None and parent is not None and email is not None: 
     queryset = queryset.filter(post=post, parent=parent, email=email) 
    elif parent is not None and author is not None and email is not None: 
     queryset = queryset.filter(parent=parent, author=author, email=email) 

    return queryset 

我不想使用額外的庫如Django的過濾器。任何想法如何寫這些簡單和可能重用不同的意見將非常讚賞。

Answer 1

你可以鏈filter調用（如你在第一次調用後，已經做了）：

if post is not None: 
    queryset = queryset.filter(post=post) 
if parent is not None: 
    queryset = queryset.filter(parent=parent) 
... 

注意if而不是elif。