在 Django Rest Framework 的响应中包含中介(通过模型) [英] Include intermediary (through model) in responses in Django Rest Framework

问题描述

我有一个关于处理 m2m/through 模型及其在 django rest 框架中的演示的问题.举个经典的例子:

I have a question about dealing with m2m / through models and their presentation in django rest framework. Let's take a classic example:

models.py:

from django.db import models

class Member(models.Model):
    name = models.CharField(max_length = 20)
    groups = models.ManyToManyField('Group', through = 'Membership')

class Group(models.Model):
    name = models.CharField(max_length = 20)

class Membership(models.Model):
    member = models.ForeignKey('Member')
    group = models.ForeignKey('Group')
    join_date = models.DateTimeField()

serializers.py:

serializers.py:

imports...

class MemberSerializer(ModelSerializer):
    class Meta:
        model = Member

class GroupSerializer(ModelSerializer):
    class Meta:
        model = Group

views.py:

imports...

class MemberViewSet(ModelViewSet):
    queryset = Member.objects.all()
    serializer_class = MemberSerializer

class GroupViewSet(ModelViewSet):
    queryset = Group.objects.all()
    serializer_class = GroupSerializer

当 GETing 一个 Member 实例时，我成功地收到了所有成员的字段及其组 - 但是我只获得了组的详细信息，没有来自 Membership 模型的额外详细信息.

When GETing an instance of Member, I successfully receive all of the member's fields and also its groups - however I only get the groups' details, without extra details that comes from the Membership model.

换句话说，我期望收到:

{
   'id' : 2,
   'name' : 'some member',
   'groups' : [
      {
         'id' : 55,
         'name' : 'group 1'
         'join_date' : 34151564
      },
      {
         'id' : 56,
         'name' : 'group 2'
         'join_date' : 11200299
      }
   ]
}

注意加入日期.

我尝试了很多解决方案，当然包括Django Rest-Framework 官方页面关于它 似乎没有人给出一个正确的简单答案 - 我需要做什么来包含这些额外的字段?我发现使用 django-tastypie 更直接，但还有一些其他问题，我更喜欢 rest-framework.

I have tried oh so many solutions, including of course Django Rest-Framework official page about it and no one seems to give a proper plain answer about it - what do I need to do to include these extra fields? I found it more straight-forward with django-tastypie but had some other problems and prefer rest-framework.

推荐答案

怎么样.....

在您的 MemberSerializer 上，定义一个字段，例如:

On your MemberSerializer, define a field on it like:

groups = MembershipSerializer(source='membership_set', many=True)

然后在您的会员序列化程序上，您可以创建:

and then on your membership serializer you can create this:

class MembershipSerializer(serializers.HyperlinkedModelSerializer):

    id = serializers.Field(source='group.id')
    name = serializers.Field(source='group.name')

    class Meta:
        model = Membership

        fields = ('id', 'name', 'join_date', )

这具有创建序列化值、组的整体效果，该值具有您想要的成员资格作为其来源，然后它使用自定义序列化程序提取您想要显示的位.

That has the overall effect of creating a serialized value, groups, that has as its source the membership you want, and then it uses a custom serializer to pull out the bits you want to display.

正如@bryanph 所评论的，serializers.field 在 DRF 3.0 中被重命名为 serializers.ReadOnlyField，所以这应该是:

as commented by @bryanph, serializers.field was renamed to serializers.ReadOnlyField in DRF 3.0, so this should read:

class MembershipSerializer(serializers.HyperlinkedModelSerializer):

    id = serializers.ReadOnlyField(source='group.id')
    name = serializers.ReadOnlyField(source='group.name')

    class Meta:
        model = Membership

        fields = ('id', 'name', 'join_date', )

适用于任何现代实现

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