如何序列化對象列表？

Question

Django-Rest-Framework 文檔 ( https://www.django-rest-framework.org/api-guide/serializers/ ) 提供了以下用於序列化對象列表的示例：

queryset = Book.objects.all()
serializer = BookSerializer(queryset, many=True)
serializer.data

我嘗試使用以下代碼執行類似操作：

@api_view(['GET'])
def postComments(request, pk):
    """
    Retrieve all comments with originalPostId = pk.
    """
    if request.method == 'GET':
        comments = Comment.objects.all()
        comments = comments.filter(originalPostId = pk)
        serializer = CommentSerializer(comments, many=True)
        if serializer.is_valid():
            return Response(serializer.data)
        logger.error(serializer.errors)

但是，立即出現以下錯誤： AssertionError: Cannot call `.is_valid()` as no `data=` keyword argument was passed when instantiating the serializer instance.

另一篇文章（ django-rest-framework：無法調用`.is_valid()`，因為在實例化序列化器實例時沒有傳遞`data=`關鍵字參數）似乎解決了這個問題，但答案表明在調用時放入data=我的CommentSerializer將用於反序列化而不是序列化，這不是我想要的。

但是，當我使用serializer = CommentSerializer(data=comments, many=True)行運行時serializer = CommentSerializer(data=comments, many=True)我收到錯誤{'non_field_errors': [ErrorDetail(string='Expected a list of items but got type "QuerySet".', code='not_a_list')]}

這是我的序列化程序，以防萬一：

    poster = UserSerializer()
    community = CommunitySerializer()
    originalPost = PostSerializer()
    class Meta:
        model = Comment
        fields = ['post', 'community', 'poster', 'originalPost', 'originalPostId']

    def create(self, validated_data):
        userData = validated_data.pop('poster')
        user = User.objects.get_or_create(username=userData['username'],
                                                       email=userData['email'],
                                                       first_name=userData['first_name'],
                                                       last_name=userData['last_name'],
                                                       password=userData['password'])[0]
        validated_data['poster'] = user
        communityData = validated_data.pop('community')
        community = Community.objects.get_or_create(name=communityData['name'])[0]
        validated_data['community'] = community

        originalPostData = validated_data.pop('originalPost')
        originalPost = Post.objects.get_or_create(id = validated_data['originalPostId'])[0]
        validated_data['originalPost'] = originalPost

        comment = Comment.objects.create(**validated_data)
        return comment```

Answer 1

@api_view(['GET'])
def postComments(request, pk):
    """
    Retrieve all comments with originalPostId = pk.
    """
    if request.method == 'GET':
        comments = Comment.objects.all()
        comments = comments.filter(originalPostId = pk)
        serializer = CommentSerializer(comments, many=True)
        return Response(serializer.data)

擺脫is_valid()檢查使它起作用。 我想我只需要相信自己吧~

Answer 2

is_valid 用於驗證用戶輸入數據，因此無需調用 is_valid。

@api_view(['GET'])
def postComments(request, pk):
    """
    Retrieve all comments with originalPostId = pk.
    """
    if request.method == 'GET':
        comments = Comment.objects.filter(originalPostId = pk).all()
        serializer = CommentSerializer(comments, many=True)
        return Response(serializer.data)