Nested Multiple choice field serialize in Django and VueJS app - django

Question

I have multiple choice nested serializer, I am able to get the value but during patch call subjects not getting updated
Here User and Subject are two models,
**Model.py**
class Subject(models.Model):
uid = models.AutoField(verbose_name='ID',
serialize=False,
auto_created=True,
primary_key=True)
ENG = "ENGLISH"
HND = "HINDI"
SUBJECT = (
(ENG, "English"),
(HND, "Hindi"),
)
subject = models.CharField(
max_length=50, choices=SUBJECT, default=ENG)
def __str__(self):
return self.subject
class User(AbstractUser):
uid = models.AutoField(verbose_name='ID',
serialize=False,
auto_created=True,
primary_key=True)
TEACHER = "Teacher"
STUDENT = "Student"
user_type = models.CharField(max_length=30, default=STUDENT)
approved = models.BooleanField(default=True)
def save(self, *args, **kwargs):
if self.user_type == User.TEACHER and self._state.adding:
self.approved = False
super().save(*args, **kwargs)
#property
def syllabus(self):
ret = self.teacher.syllabus_set.all()
if ret:
return ret
else:
return ''
Here is my serializer call
**serializers.py**
class TeacherProfileDetails(serializers.ModelSerializer):
logger = logging.getLogger(__name__)
teacher_date = AvailabilityDetails(many=True, read_only=True)
first_name = serializers.CharField(source='user.first_name', read_only=True)
last_name = serializers.CharField(source='user.last_name', read_only=True)
cities = CitySerializer(many=True, read_only=True)
subject = serializers.SerializerMethodField()
user = UserDetailsSerializer(read_only=True)
class Meta:
model = Teacher
fields = ('user', 'first_name', 'last_name',
'bio', 'teacher_cost', 'subject', 'teacher_date', 'cities')
def get_subject(self, obj):
subject_list = []
for i in obj.subject.all():
subject_list.append(i.subject)
return subject_list
Here is my views.py call
**views.py**
class TeacherListCreateAPIView(APIView):
logger = logging.getLogger(__name__)
#def create(self, request, *args, **kwargs):
def get(self, request, *args, **kwargs):
self.logger.info("Geeting TeacherListCreateAPIView information")
teacherList = Teacher.objects.filter(user__username=kwargs["username"])
self.logger.info(teacherList)
serializers = TeacherProfileDetails(teacherList, many=True)
self.logger.info(serializers.data)
return Response(serializers.data)
def patch(self, request, *args, **kwargs):
teacher = Teacher.objects.get(user__username=kwargs['username'])
serializers = TeacherProfileDetails(data=request.data, instance=teacher)
self.logger.info(serializers)
if serializers.is_valid():
serializers.save()
return Response(serializers.data, status=status.HTTP_201_CREATED)
return Response(serializers.errors, status=status.HTTP_400_BAD_REQUEST)
Here is urls.py
path('teacher/<str:username>/details',
TeacherListCreateAPIView.as_view(), name="teacher-details"),
Issue :
I am able to get the teacher details, but patch call not updating subject, looks like I am doing some mistake in TeacherProfileDetails while serializing subject

Answer 1

SerializerMethodField is read-only. So, all fields in provided serializer are read-only.
You can use SlugRelatedField serializer instead, both for read and write:
subjects = serializers.SlugRelatedField(
many=True,
slug_field='subject',
queryset=Subject.objects.all(),
)
For write better to add logic in the view to make subjects contain unique elements or even allow adding one subject from patch to already present subjects.
Or you can use two separate serializers - one for read (current one), and one for write (with just fields allowed to be changed - it can be SlugRelatedField, or even just ListField with custom update() method logic, etc).