Question

我对api/business-review/3abe3a1e-199c-4a4b-9d3b-e7cb522d6bed/的API调用目前返回以下内容：

[
    {
        "id": "3abe3a1e-199c-4a4b-9d3b-e7cb522d6bed",
        "date_time": "2016-05-31T19:18:24Z",
        "review": "Another quality job, Anna has a no fuss approach to his job and clearly takes pride in what he does. Will continue to use again and again.",
        "rating": "4.0",
        "person": "c1cc5684-1be1-4120-9d81-05aec29f352a",
        "employee": "ecdc1f99-138c-4f9f-9e1f-b959d59209aa",
        "service": "1dfa408f-d5bc-4eb2-96ae-e07e7999a01a",
    }
]

现在我要创建三个新字段：

person_name - 抓取审稿人的first_name和last_name
employee_name - 抓取员工的first_name和last_name
service_name - 抓取服务的标题

到目前为止，我已尝试过以下内容，但它不会创建任何新变量：

serializers.py

class ReviewSerializer(serializers.ModelSerializer):
    """
    Class to serialize Review objects
    """
    person_name = serializers.CharField(source='person.reviewer.first_name', read_only=True)
    employee_name = serializers.CharField(source='person.employer.first_name', read_only=True)
    service_name = serializers.CharField(source='service.title', read_only=True)

    class Meta:
        model = Review
        fields = '__all__'
        read_only_fields = 'id'

models.py

class Review(models.Model):
    """
    Review model
    """
    id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
    date_time = models.DateTimeField(blank=True, null=True, default=None)
    person = models.ForeignKey(Person, null=True, default=None, related_name='reviewer')
    employee = models.ForeignKey(Person, null=True, default=None, related_name='employee')
    review = models.TextField(null=True, default=None)
    service = models.ForeignKey(Service, null=True, default=None)
    rating = models.DecimalField(max_digits=4, decimal_places=1)

class Person(models.Model):
    """
    Person entity
    """
    id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
    first_name = models.CharField(max_length=255)
    last_name = models.CharField(max_length=255)

class Service(models.Model):
    """
    Service model
    """
    id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
    title = models.CharField(max_length=255)

Answer 1

请尝试显式添加字段名称，而不是使用__all__，fields = ['person', 'service', 'review', 'employee', 'person_name', 'service_name', 'employee_name', 'date_time']只会选择模型中存在的字段，而不是像此一样在序列化程序中定义的字段

gem 'streamio-ffmpeg', '1.0.0'

Answer 2

由于您希望将数据添加到对象的序列化表示形式，因此最好对person_name，service_name和employee_name字段使用SerializerMethodField()。

这是read-only字段。它通过调用方法获得它的价值它所附加的序列化程序类。它可以用来添加任何排序数据到对象的序列化表示。

此外，由于ForeignKey字段person，employee和service允许空值，因此当它们实际为空时，您必须处理这种情况。否则，将在序列化程序上引发AttributeError异常。

class ReviewSerializer(serializers.ModelSerializer):
    """
    Class to serialize Review objects
    """
    person_name = serializers.SerializerMethodField()
    employee_name = serializers.SerializerMethodField()
    service_name = serializers.SerializerMethodField()

    class Meta:
        model = Review
        fields = ['person', 'service', 'review', 'employee', 'person_name', 'service_name', 'employee_name', 'date_time']
        read_only_fields = 'id'

    def get_person_name(self, obj):
        try:
            person_name = obj.person.first_name + obj.person.last_name
        except AttributeError: # handle case if person is null
            return None
        else:
            return person_name

    def get_employee_name(self, obj):
        try:
            employee_name = obj.employee.first_name + obj.employee.last_name
        except AttributeError: # handle case if employee is null
            return None
        else:
            return employee_name

    def get_service_name(self, obj):
        try:
            service_name = obj.service.title
        except AttributeError: # handle case if service is null
            return None
        else:
            return service_name

在序列化程序中创建访问其他模型属性的新字段

2 个答案: