將Django Rest Framework與序列化程序一起使用時的AttributeError

Question

我正在按照這里使用Django Rest Framework的教程進行操作，並且我不斷得到關於字段的奇怪錯誤。

我的models.py有以下模型

from django.db import models

class Task(models.Model):
    completed = models.BooleanField(default=False)
    title = models.CharField(max_length=100)
    description = models.TextField()

然后我在serializers.py中的serializers.py

from rest_framework import serializers

from task.models import Task

class TaskSerializer(serializers.ModelSerializer):

    class Meta:
        model = Task
        fields = ('title', 'description', 'completed')

和我的views.py如下：

from rest_framework import status
from rest_framework.decorators import api_view
from rest_framework.response import Response

from task.models import Task
from api.serializers import TaskSerializer


    @api_view(['GET', 'POST'])
    def task_list(request):
        """
        List all tasks, or create a new task
        """
        if request.method == 'GET':
            tasks = Task.objects.all()
            serializer = TaskSerializer(tasks)
            return Response(serializer.data)

        elif request.method == 'POST':
            serializer = TaskSerializer(data=request.DATA)
            if serializer.is_valid():
                serializer.save()
                return Response(serializer.data, status=status.HTTP_201_CREATED)
            else:
                return Response(
                    serializer.errors, status=status.HTTP_400_BAD_REQUEST
                )

我的urls.py有這一行：

url(r'^tasks/$', 'task_list', name='task_list'),

當我嘗試訪問curl http://localhost:9000/api/tasks/ ，我不斷收到以下錯誤，我不知道該怎么做：

AttributeError at /api/tasks/
Got AttributeError when attempting to get a value for field `title` on serializer `TaskSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `QuerySet` instance.
Original exception text was: 'QuerySet' object has no attribute 'title'.

我錯過了什么？

Answer 1

在從queryset創建序列化程序時，簡單指定many=True ， TaskSerializer(tasks)將僅對Task一個實例起作用：

tasks = Task.objects.all()
serializer = TaskSerializer(tasks, many=True)

Answer 2

這里的問題是您正在嘗試將條目的Queryset（列表）轉換為單個條目。 解決方案就是這樣。

from rest_framework import serializers

class TaskListSerializer(serializers.ListSerializer):
    child = TaskSerializer()
    allow_null = True
    many = True

然后

if request.method == 'GET':
        tasks = Task.objects.all()
        serializer = TaskListSerializer(tasks)
        return Response(serializer.data)