Django rest 从桥模型中获取数据

Question

我想获取所有用户详细信息和所有角色的列表用户详情模型我的模型

class UserDetail(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE,
                                related_name='userdetail_user', default='111')
    cn = models.CharField(max_length=200)
    sn = models.CharField(max_length=200)
    u_id = models.CharField(max_length=200)
    display_name_cn = models.CharField(max_length=200)
    display_name_en = models.CharField(max_length=200)
    given_name = models.CharField(max_length=200)
    employee_number = models.CharField(max_length=200)
    email = models.CharField(max_length=200)
    created_at = models.DateTimeField(default=datetime.now, blank=True)
    last_login = models.DateTimeField(default=datetime.now, blank=True)

    def __str__(self):
        return self.given_name


class Role(models.Model):
    title = models.CharField(max_length=20)
    description = models.CharField(max_length=200)
    created_at = models.DateTimeField(default=datetime.now, blank=True)
    last_updated = models.DateTimeField(default=datetime.now, blank=True)
    status = models.BooleanField(default=True)

    def __str__(self):
        return self.title


class UserRole(models.Model):
    userdetail = models.ForeignKey(UserDetail, on_delete=models.CASCADE,
                                   related_name='userrole_userdetail')
    role = models.ForeignKey(Role, on_delete=models.CASCADE)
    approver = models.ForeignKey(UserDetail, on_delete=models.SET_NULL,
                                 null=True,
                                 related_name='userrole_userdetail_approver')
    created_at = models.DateTimeField(default=datetime.now, blank=True)
    last_updated = models.DateTimeField(default=datetime.now, blank=True)
    status = models.BooleanField(default=True)

我的序列化程序

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


class UserRoleSerializer(serializers.ModelSerializer):
    class Meta:
        model = UserRole
        fields = (
            'id', 'userdetail', 'role', 'approver', 'last_updated', 'status')
        depth = 1

    def to_representation(self, instance):
        representation = super(UserRoleSerializer, self).to_representation(
            instance)
        representation['userdetail'] = UserDetailSerializer(
            instance.userdetail).data
        representation['role'] = RoleSerializer(instance.role).data
        representation['approver'] = UserDetailSerializer(
            instance.approver).data
        return representation


class RoleSerializer(serializers.ModelSerializer):
    class Meta:
        model = Role
        fields = ('id', 'title', 'description', 'last_updated', 'status')


class UserDetailSerializer(serializers.ModelSerializer):
    user = UserSerializer()
    roles = serializers.SerializerMethodField(read_only=True)

    class Meta:
        model = UserDetail
        fields = ('id', 'roles', 'user', 'cn', 'sn', 'u_id', 'display_name_cn',
                  'display_name_en', 'given_name', 'employee_number', 'email',
                  'last_login')

        lookup_field = 'u_id'

    def get_roles(self, obj):

        roles = UserRole.objects.filter(userdetail=obj)
        return roles

当我尝试获取所有用户详细信息时，出现错误 "Object of type 'UserRole' is not JSON serializable".

我已经尝试序列化在 UserDetailsSerializer 的 get_roles 方法中获取的对象列表，但它没有帮助

Answer 1

在你的序列化程序中，你必须替换

 roles = serializers.SerializerMethodField(read_only=True)

有

userrole_userdetail = UserRoleSerializer(many=True, read_only=True)

这是因为你的FK关系名称必须与模型中给定的相关名称相匹配。同样在 UserRoleSerializer 中，您不需要 to_representation 方法。

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