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Django Rest Framework SerializerMethodField仅在GET请求时

django-rest-framework django

0

hancho · 技术社区 · 7 年前

我的DRF后端遇到了一个小问题。

我正在用某些模型的选项填充字段。

我对一个型号有外键要求。创建模型时,我希望将其保存在外部id下。

当我请求模型时,我希望模型中包含选项字段映射到的任何内容。

我可以使用SerializerMethodField来完成这项工作,但是当我尝试创建模型时,由于块无效,我得到一个400错误。如果删除SerializerMethodField,我可以保存,但可以从请求中获取数据库中存储的号码。

任何帮助都将不胜感激。

class BlockViewSet(ModelViewSet):
    model = apps.get_model('backend', 'Block')
    queryset = model.objects.all()
    serializer_class = serializers.BlockSerializer
    permissions = ('All',)

    def create(self, request, format=None):
        data = request.data 
        data['user'] = request.user.id
        data['goal'] = WorkoutGoal.objects.get(goal=data['goal']).id
        block = serializers.BlockSerializer(data=data, context={'request': request})
        if block.is_valid():
            new_block = block.save()
            return Response({'block': {'name': new_block.name, 'id': new_block.id}}, status=status.HTTP_201_CREATED)
        else:
            return Response(block.errors, status=status.HTTP_400_BAD_REQUEST)

class WorkoutGoalSerializer(serializers.ModelSerializer):
    class Meta:
        model = apps.get_model('backend', 'WorkoutGoal')
        fields = ('goal',)

    goal = serializers.SerializerMethodField(read_only=True, source='get_goal')

    def get_goal(self, obj):
        return dict(WorkoutGoal.GOALS).get(obj.goal)

class BlockSerializer(serializers.ModelSerializer):
    workout_count = serializers.IntegerField(required=False)
    completed_workouts = serializers.IntegerField(required=False)
    goal = WorkoutGoalSerializer()

    class Meta:
        model = apps.get_model('backend', 'Block')
        read_only_fields = ('workout_count', 'completed_workouts')
        fields = read_only_fields + ('id', 'name', 'user', 'created', 'goal')

上面的代码返回正确的选择,但我无法保存在下面。移除 goal = WorkoutGoalSerializer() 它保存但不返回映射的选择。

2 回复 | 直到 7 年前

1

2

JPG 7 年前

我想这会很有魅力的,

class WorkoutGoalSerializer(serializers.ModelSerializer):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if 'request' in self.context and self.context['request'].method == 'GET':
            self.fields['goal'] = serializers.SerializerMethodField(read_only=True, source='get_goal')

    class Meta:
        model = apps.get_model('backend', 'WorkoutGoal')
        fields = ('goal',)

    goal = serializers.SerializerMethodField(read_only=True, source='get_goal')  # remove this line

    def get_goal(self, obj):
        return dict(WorkoutGoal.GOALS).get(obj.goal)

这是怎么回事?
它将重新启动 goal 字段 SerializerMethodField ,如果重新计算的方法是 GET .

记住一件事, 你应该把线拔掉 ,

goal = serializers.SerializerMethodField(read_only=True, source='get_goal')

2

0

Ykh 7 年前

序列化程序.py

class BlockCreateSerializer(serializers.ModelSerializer):
    workout_count = serializers.IntegerField(required=False)
    completed_workouts = serializers.IntegerField(required=False)

    class Meta:
        model = apps.get_model('backend', 'Block')
        read_only_fields = ('workout_count', 'completed_workouts')
        fields = read_only_fields + ('id', 'name', 'user', 'created', 'goal')

class BlockSerializer(serializers.ModelSerializer):
    workout_count = serializers.IntegerField(required=False)
    completed_workouts = serializers.IntegerField(required=False)
    goal = WorkoutGoalSerializer()

    class Meta:
        model = apps.get_model('backend', 'Block')
        read_only_fields = ('workout_count', 'completed_workouts')
        fields = read_only_fields + ('id', 'name', 'user', 'created', 'goal')

视图.py

class BlockViewSet(ModelViewSet):
    model = apps.get_model('backend', 'Block')
    queryset = model.objects.all()
    serializer_class = serializers.BlockSerializer
    permissions = ('All',)

    def get_serializer_class(self):
        if self.action == 'create':
            return serializers.BlockCreateSerializer
        else:
            return self.serializer_class

    def create(self, request, format=None):
        data = request.data 
        data['user'] = request.user.id
        data['goal'] = WorkoutGoal.objects.get(goal=data['goal']).id
        block = self.get_serializer(data=data)
        if block.is_valid():
            new_block = block.save()
            return Response({'block': {'name': new_block.name, 'id': new_block.id}}, status=status.HTTP_201_CREATED)
        else:
            return Response(block.errors, status=status.HTTP_400_BAD_REQUEST)

覆盖 get_serializer_class 返回不同的 serializer_class 对于 create 以及其他行动( list\retrieve\update\partial_update )