Django REST框架GET嵌套序列化器产生错误: 'RelatedManager' object has no attribute 'datafile_set' "

Question

我有一个 2 层深的嵌套序列化器堆栈:

class ToolSerialier(serializers.ModelSerializer):
    input = ToolInputSerializer()

    class Meta:
        model = Tool
        fields = ('docker_image', 'input')

class ToolInputSerializer(serializers.ModelSerializer):
    datafile_set = ToolInputDatafileSerializer(many=True)

    class Meta:
        model = ToolInput
        fields = ('datafile_set', )

class ToolInputDatafileSerializer(serializers.ModelSerializer):
    class Meta:
        model = ToolInputDatafile
        fields = ('name', 'file')

以及各自的型号:

class Tool(models.Model):
    docker_image = models.CharField(max_length=255, null=True, blank=True)

class ToolInput(models.Model):
    tool = models.ForeignKey(Tool, related_name="input")

class ToolInputDatafile(models.Model):
        tool_input = models.ForeignKey(ToolInput, related_name="datafile_set")
        name = models.CharField(max_length=255)
        file = jsonfield.JSONField()

现在，当我向 ToolSerializers 列表端点发送 GET 请求时，我收到一条错误消息:

/api/tool/处的属性错误

Got AttributeError when attempting to get a value for field `datafile_set` on serializer `ToolInputSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `RelatedManager` instance. 
Original exception text was: 'RelatedManager' object has no attribute 'datafile_set'.

显然，由于某种原因，ToolInput 的 RelatedManager 上没有调用 get() 方法，并且无法访问 datafile_set 属性。

为什么？我应该引入哪些修复措施？

Answer 1

您缺少一个 many=True 参数:

class ToolSerialier(serializers.ModelSerializer):
    input = ToolInputSerializer(many=True)

这是必需的，因为您有反向 FK。