在Django rest框架中使用相同的序列化器类，但在视图中使用不同的操作

Question

我有一个模型集视图，其中根据需求定义了不同的定制函数。我必须编写另一个get函数，我想在其中使用相同的序列化器类。但是我在序列化器类pkfield中定义的字段但是对于get函数，我希望它是字符串字段而不是pk字段。如何做到这一点?

另外，我已经定义了depth=1，这也不起作用。

class Class(TimeStampAbstractModel):
teacher = models.ForeignKey(
Teacher,
on_delete=models.CASCADE,
null=True,
related_name="online_class",
)
subject = models.ForeignKey(
Subject,
on_delete=models.SET_NULL,
null= True,
related_name= "online_class",
)
students_in_class = models.ManyToManyField(Student, related_name="online_class")

我的观点:

class ClassView(viewsets.ModelViewSet):
queryset = Class.objects.all()
serializer_class = ClassSerializer
serializer_action_classes = {
'add_remove_students': AddStudentstoClassSerializer,
'get_all_students_of_a_class': AddStudentstoClassSerializer,
}
def get_serializer_class(self):
"""
returns a serializer class based on the action
that has been defined.
"""
try:
return self.serializer_action_classes[self.action]
except (KeyError, AttributeError):
return super(ClassView, self).get_serializer_class()

def add_remove_students(self, request, *args, **kwargs):
""" 
serializer class used is AddStudentstoClassSerializer
"""
def get_all_students_of_a_class(self,request,pk=None):
"""
for this I function too, I want to use the same AddStudentstoClassSerializer class but 
there is a problem. The field students_in_class is already defined as pkfield, whereas I
want to use it as a stringfields in the response of this function
""""

我的序列化器:

class AddStudentstoClassSerializer(serializers.ModelSerializer):
students_in_class = serializers.PrimaryKeyRelatedField(
many=True, queryset=Student.objects.all()
)
class Meta:
model = Class
fields = ["students_in_class"]
depth = 1
def update(self, instance, validated_data):
slug = self.context["slug"]
stu = validated_data.pop("students_in_class")
/................other codes....../
return instance

在这里，我们可以看到student_in_class被定义为pkfield，这在使用更新api时是ok的，但是当我想使用get api并调用get_all_students_of_a_class时，我希望该字段是stringfield或其他字段。怎么做呢?depth= 1也不工作。

更新:

输入下列内容，但仍不能正常工作:

def to_representation(self, instance):
rep = super().to_representation(instance)
# rep["students_in_class"] = instance.students_in_class
rep['students_in_class'] = StudentSerializer(instance.students_in_class).data
return rep
class StudentSerializer(serializers.ModelSerializer):
user = serializers.PrimaryKeyRelatedField(read_only=True)
class Meta:
model = Student
fields = ['user', 'college_name', 'address']

我得到的响应是

{
"students_in_class": {}
}

是空字典。应该怎么做!

Answer 1

您可以像这样重写您的to_representation方法。

class AddStudentstoClassSerializer(serializers.ModelSerializer):
students_in_class = serializers.PrimaryKeyRelatedField(
many=True, queryset=Student.objects.all()
)
class Meta:
model = Class
fields = ["students_in_class"]

def to_representation(self, instance):
data = {
"students_in_class": # Write your logic here
}
return data
def update(self, instance, validated_data):
slug = self.context["slug"]
stu = validated_data.pop("students_in_class")
/................other codes....../
return instance