如何在 django rest 框架模型中创建 created_by 字段？答案

【问题标题】：How to create a created_by field in django rest framework model?如何在 django rest 框架模型中创建 created_by 字段？
【发布时间】：2016-06-09 01:52:11
【问题描述】：

我想在 django rest 框架模型中创建一个 created_by 字段。

它应该包含当前登录用户的user_id，并且它应该是我不需要在JSON格式的POST请求期间发送它，它应该来自请求本身，我如何使用django rest框架序列化程序来实现它。

models.py 文件：

class Company(models.Model):
    """Company model for information about company."""

    created_by = models.ForeignKey(User, null= True, blank= True, on_delete=models.CASCADE)
    company_name = models.CharField(max_length=100)

serializers.py 文件：

class CompanySerializer(serializers.ModelSerializer):
"""Serializer for companies."""

    class Meta:
        model = Company
        fields = ('id', 'created_by', 'company_name')

v1.py 文件：

class CompanyList(APIView):
"""Get and post companies data."""

    def get(self, request, format=None):
        """Get companies data.."""
        companies = Company.objects.all()
        serialized_companies = CompanySerializer(companies, many=True)
        return Response(serialized_companies.data)

    def post(self, request, format=None):
        """Post companies data."""
        serializer = CompanySerializer(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)

【问题讨论】：

标签： django python-2.7 django-models django-rest-framework django-serializer

【解决方案1】：

方法一：使用CurrentUserDefault()选项

您可以将created_by 字段中的default 参数作为serializers.CurrentUserDefault() 传递，这会将其值设置为当前用户。

class CompanySerializer(serializers.ModelSerializer):
"""Serializer for companies."""

    class Meta:
        model = Company
        fields = ('id', 'created_by', 'company_name')
        extra_kwargs = {'created_by': {'default': serializers.CurrentUserDefault()}}

方法二：在serializer.save()中传递user

您可以将字段created_by 设置为read_only，然后将request.user 传递给serializer.save()。

serializers.py

class CompanySerializer(serializers.ModelSerializer):
"""Serializer for companies."""

    class Meta:
        model = Company
        fields = ('id', 'created_by', 'company_name')
        extra_kwargs = {'created_by': {'read_only':True}}

v1.py

class CompanyList(APIView):
"""Get and post companies data."""

    def post(self, request, format=None):
        """Post companies data."""
        serializer = CompanySerializer(data=request.data)
        if serializer.is_valid():
            serializer.save(created_by=request.user) # pass current user
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

【讨论】：

【解决方案2】：

您可以将serializers.CurrentUserDefault() 用作CompanySerializer 中created_by 字段的默认值，并将该字段设为read_only=True。

请参阅文档here。

【讨论】：

不知何故无法正常工作。它给出了 IntegrityError: Column 'created_by_id' cannot be null。如果我离开 read_only=True，它可以工作。但是我也可以将其设置为其他内容，例如另一个用户...
@gabn88 同意，我也看到了这一点。 Rahul Gupta 的两种方法都对我有用。这个没有。
它真的很优雅，但对我也不起作用，我得到同样的错误django.db.utils.IntegrityError: null value in column "created_by_id" violates not-null constraint

【解决方案3】：

试试这个解决方案

models.py 文件

class Student(models.Model):
    middel_name = models.CharField(max_length=100)
    user = models.OneToOneField(User)

这是我的序列化程序文件

class GetStudentUserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ('id','username', 'email', 'first_name', 'last_name')

class GetStudentSerializer(serializers.ModelSerializer):
    user = GetStudentUserSerializer('user.username')
    class Meta:
        model = Student
        fields = ('id','middel_name','user')
        depth = 1

    def create(self, validated_data):
        print "hello"
        student_data = validated_data.pop('student', None)
        user = super(GetStudentSerializer, self).create(validated_data)
        self.create_or_update_student(user, student_data)
        return user

    def update(self, instance, validated_data):
        student_data = validated_data.pop('student', None)
        self.create_or_update_student(instance, student_data)
        return super(GetStudentSerializer, self).update(instance, student_data)

    def create_or_update_student(self, user, student_data):
        student, created = Student.objects.get_or_create(user=user, defaults=student_data)
        if not created and student_data is not None:
        super(GetStudentSerializer, self).update(instance, student_data)

【讨论】：