Django - 多对多字段的嵌套序列化

Question

我正在尝试创建 API，但序列化程序失败。 我无法弄清楚出了什么问题。

查看：

elif request.method == 'POST':
    data = { 'user':request.data.get('user'),'skill_item':request.data.get('new_user_skill')}
    serializer = UserSkillSerializer(data=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)  

序列化器：

    class UserModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ('username', 'first_name', 'last_name', 'email')
        extra_kwargs = {
            'username': {
                'validators': [UnicodeUsernameValidator()],
            }
        }    


class UserProfileSerializer(serializers.ModelSerializer):
    skill_item =SkillSerializer(read_only=True,many=True) 
    class Meta:
        model = User
        fields = ('username', 'first_name', 'last_name', 'email','skill_item')
        extra_kwargs = {
            'username': {
                'validators': [UnicodeUsernameValidator()],
            }
        }   

        def create(self, validated_data):

            user = UserModelSerializer.create(UserModelSerializer(),username=validated_data.get('username'))
            user.save()

            UserProfile.objects.create(user=user, user_skills=skill_item)
            return user

class UserSkillSerializer(serializers.ModelSerializer):
    user = UserProfileSerializer(required=True)
    skill_item = SkillSerializer(required=True)
    class Meta:
        model = UserSkill
        fields= '__all__'

    def create (Self,validated_data):
        user_data = validated_data.pop('user')
        user = UserProfileSerializer.create(UserProfileSerializer(),validated_data=user_data)
        skill_data = validated_data.pop('skill_item')
        skill = SkillSerializer.create(SkillSerializer(),validated_data=skill_data)
        user_skill, created = UserSkill.objects.update_or_create(user=user,skill_item=skill_item)

        return user_skill
class SkillSerializer(serializers.ModelSerializer):

    class Meta:
        model = Skill
        fields = '__all__'
        extra_kwargs = {
            'skill_name': {
                'validators': [UnicodeUsernameValidator()],
            }
        } 

型号：

# This class will more or less map to a table in the database and defines skills at the application level
class Skill (models.Model):
    # this defines a required name that cannot be more than 100 characters.
    skill_name = models.CharField(max_length=100,unique=True)
    class Meta:
        app_label = "wantedly_webapp"

# This class will more or less map to a table in the database and defines the many to many relationship between user-skill, this is our intermediate model
class UserSkill(models.Model):
    """ A Model for representing skill in user profile """
    unique_together = (('user', 'skill_item'),)

    user = models.ForeignKey('UserProfile',on_delete=models.CASCADE,related_name='current_user_skills')

    skill_item = models.ForeignKey(Skill,on_delete=models.CASCADE)

    def __str__(self):
        """Return a human readable representation of the model instance."""
        return "{}".format(self.skill_item.skill_name)

# this class adds a Many to Many field in existing django-rest auth UserProfile class for  user and his/her skills 
class UserProfile(models.Model):
    user = models.OneToOneField('auth.User',unique=True,on_delete=models.CASCADE,related_name='user_profile')
    user_skills = models.ManyToManyField(
            Skill,
            through='UserSkill',
            through_fields=('user','skill_item')
        )

我得到的错误基本上是由于我对视图的错误请求而发生的，该请求失败了

serialzer.is_valid()

我不确定为什么我的 UserProfileSerialzer 无法正确序列化。

编辑 1

我现在面临以下错误：

    {
        "user": {
            "non_field_errors": [
                "Invalid data. Expected a dictionary, but got User."
            ]
        },
        "skill_item": {
            "non_field_errors": [
                "Invalid data. Expected a dictionary, but got Skill."
            ]
        }

}

我相信这是因为我的序列化程序无法处理外键的嵌套关系和多对多关系。

编辑 2 - 我现在面临以下错误 -

 File "C:\code\django\wantedly\src\wantedly_webapp\serializers\UserSkillSerializer.py", line 49, in create
   user = UserProfileSerializer.create(UserProfileSerializer(),validated_data=user_data)

/api/v1/user/skills/ UNIQUE 约束处的 IntegrityError 失败： auth_user.username

Answer 1

我相信您的问题不在serializer.is_valid() 行，而是在尝试呈现以下错误的那一行：

return Response({serializer.errors}, status=status.HTTP_400_BAD_REQUEST)

这将失败，因为serializer.errors 是ReturnDict，而您正尝试使用{} 语法对其进行设置。改为使用：

return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)