过滤嵌套关系 Django Rest Framework

Question

我有两个模型，如下所示：

class Subject(models.Model):

   subject_code = models.CharField(max_length=12, unique=True)
   name = models.CharField(max_length=100)
   dept_code = models.CharField(max_length=6)

和...

class Subject_assessment(models.Model):    
   subject_code = models.ForeignKey(Subject, related_name='sub_assessments')
   year = models.CharField(max_length=4)
   name = models.CharField(max_length=50)

我以这样一种方式创建了我的序列化，当我检索一个主题时，我也会检索与该主题相关的评估。我正在使用以下序列化程序来完成此操作：

class AssessmentsSerializer(serializers.ModelSerializer):
class Meta:
    model = Subject_assessment
    fields = (
        "subject_code", "year", "name"
    )

class SubjectSerializer(serializers.ModelSerializer):
sub_assessments = AssessmentsSerializer(many=True)
class Meta:
    model = Subject
    fields = (
        "subject_code", "name", "dept_code",            
        "sub_assessments"
    )

这段代码按预期完美运行，因为它给了我这样的结果：

{
 "subject_code":"ECR2243",
 "name":"Statistics",
 "dept_code":"Stats",
 "sub_assessments":[
     {
       "subject_code":"ECR2243",
       "year":"2017",
       "name":"Test 1"
     },
     {
       "subject_code":"ECR2243",
       "year":"2016",
       "name":"Test 1"
     }
 ]
}

我的问题是我只想检索特定年份的评估。例如，如果我通过2017 年作为感兴趣的年份，我不希望像我目前得到的那样检索2016 年的评估。

任何人都可以帮助我如何构建我的代码以实现这一目标。先感谢您。

---

编辑1 我的views.py如下：

class  SubjectViewSet(viewsets.ModelViewSet):
serializer_class = SubjectSerializer
lookup_field = 'subject_code'

def get_queryset(self):
    qry_subject_code = self.request.GET.get('subject_code')
    retrieved_sub = Subject.objects.filter(subject_code=qry_subject_code)
    return retrieved_sub

Answer 1

这是对我有用的解决方案：

class FilteredAssessmentsSerializer(serializers.ListSerializer):
    def to_representation(self,data):
       qry_year = self.context['request'].GET.get('year')
       data = data.filter(year=qry_year)
       return super(FilteredAssessmentsSerializer,  self).to_representation(data)

class AssessmentsSerializer(serializers.ModelSerializer):
   class Meta:
      model = Subject_assessment
      list_serializer_class = FilteredAssessmentsSerializer
      fields = '__all__'

class SubjectSerializer(serializers.ModelSerializer):
   sub_assessments = AssessmentsSerializer(many=True)
   class Meta:
       model = Subject
       fields = (
          "subject_code", "name", "dept_code",
          "faculty_code", "university_code", "description",
          "sub_assessments"
       )

参考：我结合了以下解决方案，想出了一个适合我的解决方案。

如何将过滤器应用于 Django REST 框架中的嵌套资源？

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