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AssertionError when calling put or create in Django Rest Framework

I am trying to update my Teachers view in DRF by instead of including the link to the department field, I would display the name of the department. When I added the PrimaryKeyRelated field, I was able to see the department.name but couldnt use update or create within DRF. Is there a way I could change the display without causing the need for the methods or is that not the case?
Error
The `.update()` method does not support writable dotted-source fields by default.
Write an explicit `.update()` method for serializer `school.serializers.TeacherSerializer`, or set `read_only=True` on dotted-source serializer fields.
The `.create()` method does not support writable dotted-source fields by default.
Write an explicit `.create()` method for serializer `school.serializers.TeacherSerializer`, or set `read_only=True` on dotted-source serializer fields.
models.py
class Department(models.Model):
name = models.CharField(max_length=300)
def __str__(self):
return self.name
class Teacher(models.Model):
name = models.CharField(max_length=300)
department = models.ForeignKey(Department, on_delete=models.CASCADE)
tenure = models.BooleanField()
def __str__(self):
return f'{self.name} teaches {self.department}'
# dont need success url if get_absolute_url on create and update view
def get_absolute_url(self):
return reverse('teacher', kwargs={'pk': self.pk})
serializers.py
class TeacherSerializer(serializers.HyperlinkedModelSerializer):
department = serializers.PrimaryKeyRelatedField(
source='department.name', queryset=Department.objects.all())
class Meta:
model = Teacher
fields = ['url', 'name', 'department', 'tenure']
class DepartmentSerializer(serializers.HyperlinkedModelSerializer):
teacher_set = TeacherSerializer(many=True, required=False)
class Meta:
model = Department
fields = ['url', 'name', 'teacher_set']
views.py
class TeacherViewSet(viewsets.ModelViewSet):
queryset = Teacher.objects.all()
serializer_class = TeacherSerializer
permission_classes = [permissions.IsAuthenticatedOrReadOnly]
class DepartmentViewSet(viewsets.ModelViewSet):
queryset = Department.objects.all()
serializer_class = DepartmentSerializer
permission_classes = [permissions.IsAuthenticatedOrReadOnly]

have you tried add related_name for model Teacher in field foreign key and call in serializers? link to docs

How to link login user to post that he created?

I'm learning django and I made the tutorial on django site. I thought that I could link user to poll that he created but I'm struggling with it. When I'm logged in and creating a poll I can't see user name. In database column author_id has value null. I would appreciate every help.
Here is my code
from django.db import models
from django.utils import timezone
import datetime
from django.contrib import auth
# Create your models here.
User = auth.get_user_model()
class Question(models.Model):
question_text = models.CharField(max_length=200)
author = models.ForeignKey(User, on_delete=models.CASCADE, null=False)
def __str__(self):
return self.question_text
class Choice(models.Model):
question = models.ForeignKey(Question, on_delete=models.CASCADE)
choice_text = models.CharField(max_length=200)
votes = models.IntegerField(default=0)
def __str__(self):
return self.choice_text
class User(auth.models.User, auth.models.PermissionsMixin):
def __str__(self):
return "#{}".format(self.username)
forms.py:
class UserCreateForm(UserCreationForm):
class Meta:
fields = ('username', 'email', 'password1', 'password2')
model = get_user_model()
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['username'].label = 'Display Name'
self.fields['email'].label = 'Email Address'
class CreatePollForm(forms.ModelForm):
class Meta:
model = Question
fields = ('question_text',)
and views.py
class CreatePoll(LoginRequiredMixin, generic.CreateView):
form_class = forms.CreatePollForm
success_url = reverse_lazy('pollapp:index')
template_name = 'polls/createPoll.html'

Since your CreatePollForm only assigns the question_text field, you need to assign the author in code. A CreateView is a FormView which does the saving of the form in its form_valid() method. So in your CreateView, you want to override that method:
# in class CreatePoll
def form_valid(self, form):
question = form.save(commit=False) # fetch the new question, don't save
question.author = self.request.user # assign the user
question.save() # now save
return super().form_valid(form)
It isn't clear how you could end up with a null value for the author_id, that should have raised an IntegrityError. Are you sure you ran makemigrations and migrate in the current state?

How to check a form field for a specific attribute in that field's m2m key

I have a form that allows the user to pick several vans (many-to-many relationship). Each van has a boolean attribute named "available". I want to only show the vans whose "available" attribute is set to "True". How do I do this in the forms.py file?
I know that this could possibly be done in the template, but I did not want to create a new form-template with each individual field written out. I wanted to know if this functionality could be done in the forms.py file or in the class based view. I believe that doing it that way would be a bit cleaner. I've look into the validators but I don't think this is the way to go. Maybe I need to run a query set in the form file that checks the attribute before passing it to the form template?
views.py
def post(self, request):
"""Take in user data, clean it, and then post it to the database."""
form = self.form_class(request.POST) # pass in the user's data to that was submitted in form
if form.is_valid():
trip = form.save(commit=False) # create an object so we can clean the data before saving it
# now get the clean and normalize the data
first_name = form.cleaned_data['first_name']
last_name = form.cleaned_data['last_name']
trip_start = form.cleaned_data['trip_start']
trip_end = form.cleaned_data['trip_end']
van_used = form.cleaned_data['van_used']
trip.save()
forms.py
class TripForm(forms.ModelForm):
"""This class will be used to build trips."""
class Meta:
"""Specifying the database and fields to use."""
model = trips
fields = ['first_name', 'last_name', 'comments','trip_start', 'trip_end', 'van_used']
models.py
class trips(models.Model):
class Meta:
verbose_name_plural = "trips"
van_used = models.ManyToManyField(vans)
class vans(models.Model):
class Meta:
verbose_name_plural = "vans"
vanName = models.CharField(max_length=30, unique=True, blank=False)
available = models.BooleanField(default=True, blank=False)
# set up how the vans will be referenced in the admin page
def __str__(self):
return self.vanName
The final form that is rendered would only show the vans whose "available" attribute is set to True. Thanks in advance.

You have to override queryset for van_used field in form like this.
class TripForm(forms.ModelForm):
"""This class will be used to build trips."""
class Meta:
"""Specifying the database and fields to use."""
model = trips
fields = ['first_name', 'last_name', 'comments','trip_start', 'trip_end', 'van_used']
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['van_used'].queryset = vans.objects.filter(available=True)

Serializer works in the Django shell but fails in the view

I have those models:
class ServiceCategory(models.Model):
class Meta:
db_table = 'service_categories'
category = models.CharField(max_length=24)
def __str__(self):
return self.category
class Service(models.Model):
class Meta:
db_table = 'services'
service = models.CharField(max_length=24)
category = models.ForeignKey('ServiceCategory')
def __str__(self):
return self.service
And their serializers:
class ServiceCategorySerializer(serializers.ModelSerializer):
class Meta:
model = ServiceCategory
fields = ('id', 'category')
class ServiceSerializer(serializers.ModelSerializer):
category = ServiceCategorySerializer()
class Meta:
model = Service
fields = ('id', 'service', 'category')
After this setup, I quickly bumped into a problem creating a new Service via its associated ServiceSerializer: I have to also pass a complete ServiceCategory with all its fields even though I only need its id. The ServiceCategory above looks simple enough but that's hardly the case since I've omitted a lot of its other fields for brevity.
So passing the complete attributes of a ServiceCategory into a form on the front end seemed terribly inefficient to me so I tried another approach:
class UpsertServiceSerializer(serializers.ModelSerializer):
category = serializers.IntegerField() # not ServiceCategorySerializer()
class Meta:
model = Service
fields = ('service', 'category')
def create(self, data):
c = ServiceCategory.objects.get(pk=data['category'])
return Service.objects.create(service=data['service'], category=c)
My intention is to use UpsertServiceSerializer for creates and updates, with ServiceSerializer now being used for reads. UpsertServiceSerializer worked without a problem in the Django shell — the create goes through with me having to pass just the id of the ServiceCategory instead of all its attributes and a new Service object is indeed added to the database — but when I make a POST request via Postman, I get this error:
TypeError at /services
int() argument must be a string, a bytes-like object or a number, not 'ServiceCategory'
So I tried a new version of UpsertServiceSerializer:
class UpsertServiceSerializer(serializers.Serializer):
service = serializers.CharField()
category = serializers.IntegerField()
def create(self, data):
c = ServiceCategory.objects.get(pk=data['category'])
return Service.objects.create(service=data['service'], category=c)
Notice that in the new version, I'm subclassing serializers.Serializer instead of serializers.ModelSerializer, and there's no class Meta inside it. This version is no different, it also passes in the Django shell but fails in the view with the same TypeError.
Here's the view:
#api_view(['GET', 'POST'])
def services(request):
if request.method == 'GET':
services = Service.objects.all()
serializer = ServiceSerializer(services, many=True)
return Response(serializer.data)
elif request.method == 'POST':
serializer = UpsertServiceSerializer(data=request.data)
if serializer.is_valid():
serializer.save()
return Response(serializer.data, status=status.HTTP_201_CREATED)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
So what am I doing wrong?

It is common problem with understanding about how related fields work in serializer. ForeignKey by default use PrimaryKeyRelatedField so you don't need an IntegerField, even though you don't need overriding create method.
class UpsertServiceSerializer(serializers.ModelSerializer):
class Meta:
model = Service
fields = ('service', 'category')
Passing pk for category will just work. In the case when you need special layout for category model not a plain pk, you could write you own to_representation method.
class UpsertServiceSerializer(serializers.ModelSerializer):
...
def to_representation(self, instance):
representation = super(UpsertServiceSerializer, self).to_representation(instance)
representation['category'] = ServiceCategorySerializer(instance.category).data
return representation

Django How can I save two different class which are connected each other by OneToOne relationship in a form at once?

Let me explain what my problem is in more detail.
First I have a class 'UserInfo' which connected to User class of django.contrib.auth.models like below
models.py
class UserInfo(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
phone = models.CharField(max_length=15,blank=True,unique=True)
position = models.CharField(max_length=15,blank=True,unique=True)
class Meta:
default_permissions = ()
def __str__(self):
return self.position
then I wanted to use ModelForm because I can write less codes. The reason why I made CreateNewUser class is that I wanted to let user can see only [username, email, groups, user_permissions] and control those. (to prevent them to select superuser or staff or inactive options)
forms.py
class CreateNewUserInfo(forms.ModelForm):
class Meta:
model = UserInfo
fields = '__all__'
class CreateNewUser(forms.ModelForm):
class Meta:
model = User
fields = ['username', 'email', 'groups', 'user_permissions']
problem happened in here. I wanted to use FormView to use generic view with class typed view so that I can write less codes(concise code). there is attribute named 'form_class' and I couldn't put two different class with it. I wanted to put different two class to one form with generic view.
views.py
class TestView(FormView):
form_class = CustomForm
template_name = 'manager/alltoall.html'
def form_valid(self, form):
At the end, I made new class in forms.py and wrote every field which I need like below.
forms.py
class CustomForm(forms.Form):
username = forms.CharField(initial='testname',max_length=150)
email = forms.EmailField()
phone_number = forms.CharField(max_length=15)
position = forms.CharField(max_length=15)
views.py
class TestView(FormView):
form_class = CustomForm
template_name = 'manager/alltoall.html'
def form_valid(self, form):
username = form.cleaned_data['username']
email = form.cleaned_data['email']
phone_number = form.cleaned_data['phone_number']
position = form.cleaned_data['position']
with transaction.atomic():
user = User.objects.create(username=username,email=email)
userinfo = UserInfo.objects.create(user=user,phone=phone_number,position=position)
userinfo.save()
user.save()
return super(TestView, self).form_valid(form)
Is there anyway to use ModelForm and FormView to show two different class in a form at the same time? Additionally, I used transaction like above because I wanted to save data in database with two different class. Is it right approach or Is there any other way to do that more conveniently(or efficiently) with built in functions in django?
Thank you for taking your time to read all. I wonder if it is too long, but I wanted to deliver what I wanted to know exactly. Thank you!