DjangoRestFramework - 正确添加“required = false”的方法到ModelSerializer字段？ [英] DjangoRestFramework - correct way to add "required = false" to a ModelSerializer field?

问题描述

这是我的序列化程序：

class PostSerializer(serializers.ModelSerializer):

    class Meta:
        model = Post
        fields = ('user', 'post', 'reblog',)

    def create(self, validated_data):
        post = Post(
                user =  validated_data['user'],
                post = validated_data['post'],
        )

        post.save() 

        # manually create a list of "reblog" users
        post.reblog.add(validated_data['user'])

        return post

这是我的模型：

class Post(models.Model):
    user = models.ForeignKey(User)
    post = models.CharField(max_length=400)
    reblog = models.ManyToManyField(User)

现在，我不希望我的reblog字段在数据库中永远是空的（它可以是一个空列表，但不为null）。所以我没有在模型字段中设置null = True。然而，最终用户不必在创建帖子时提供reblog用户列表（我将在create（）mtehod中手动进行）。

Now, I don't want my reblog field to ever be null in the database (it can be an empty list, but not null). So I did not set "null=True" in the model field. However, the end user should not have to provide a list of "reblog" users when creating a post (I'll do that manually in the create() mtehod).

我知道这里： http：//www.django- rest-framework.org/api-guide/fields/#core-arguments 说，我可以向序列化程序字段添加required = false，但是我在我的序列化程序中使用的字段直接来自模型（即，fields =（'reblog'））。

I know that here: http://www.django-rest-framework.org/api-guide/fields/#core-arguments it says I can add "required = false" to a serializer field but the fields I am using in my serializer are directly coming from the model (i.e., fields = ('reblog')).

从我的理解，我不能添加required = false到我的模型，因为这里：
https://docs.djangoproject.com/en/1.8/ref/models/字段/ 它没有提到必需作为模型字段的参数。

From my understanding, I can't add "required = false" to my model because here: https://docs.djangoproject.com/en/1.8/ref/models/fields/ it does not mention "required" as a parameter to a model field.

正如上所述，我如何获取我的reblogModelSerializer字段在serailzation / deserialization期间不需要？

With that said, how can I get my "reblog" ModelSerializer field to not be required during serailzation / deserialization?

编辑：处理发送请求的视图是：

the view which handles the post request sent is:

class post_list(APIView):
    """
    List all posts or create a new post.
    """
    permission_classes = (IsAuthenticated,)

    def get(self, request):
        posts = Post.objects.all()
        serializer = PostSerializer(posts, many=True)
        return Response(serializer.data)

    def post(self, request):
        serializer = PostSerializer(data=request.DATA)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

pip freeze：

pip freeze:

You are using pip version 6.1.1, however version 7.1.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Django==1.8
djangorestframework==3.1.1
uWSGI==2.0.10

推荐答案

将参数 blank = True 添加到mod el字段：

Add the parameter blank=True to the model field:

class Post(models.Model):
    user = models.ForeignKey(User)
    post = models.CharField(max_length=400)
    reblog = models.ManyToManyField(User, blank=True)
                                         #^^^^^^^^^^

现在，请求上可能会省略参数，但可能不会是 NULL 值。

Now, the parameter may be omitted on requests, but it may never be a NULL value.

urls.py （带有 serializers.py 基本上是内联的）：

urls.py (with serializers.py essentially inlined):

from django.conf.urls import url, include
from rest_framework import routers, serializers, viewsets
from proj.models import Post



# Serializers define the API representation.
class PostSerializer(serializers.ModelSerializer):

    class Meta:
        model = Post
        fields = ('user', 'post', 'reblog',)

    def create(self, validated_data):
        post = Post(
                user =  validated_data['user'],
                post = validated_data['post'],
        )

        post.save() 

        # manually create a list of "reblog" users
        post.reblog.add(validated_data['user'])

        return post
class PostViewSet(viewsets.ModelViewSet):
    queryset = Post.objects.all()
    serializer_class = PostSerializer

# Routers provide an easy way of automatically determining the URL conf.
router = routers.DefaultRouter()
router.register(r'Post', PostViewSet)

# Wire up our API using automatic URL routing.
# Additionally, we include login URLs for the browsable API.
urlpatterns = [
    url(r'^', include(router.urls)),
    url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework'))
]

models.py ：

from django.contrib.auth.models import User
from django.db import models

class Post(models.Model):
    user = models.ForeignKey(User)
    post = models.CharField(max_length=400)
    reblog = models.ManyToManyField(User, blank=True,related_name='reblog_users')

现在，当我发送POST请求：

Now, when I send the POST request:

{
    "user": 1,
    "post": "foo"
}

它返回：

{
    "user": 1,
    "post": "foo",
    "reblog": [
        1
    ]
}

pip freeze ：

Django==1.8.4
djangorestframework==3.2.4

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