Django HiddenField value generated on Views - django

Question

Overview: need to generate a codename value for a hidden field in order to send it to an external API (1) and after that include the generated codename field in database (2).
Issue: How can I send the generated codename (HiddenField) to database?
models.py
class Category(Model):
name = models.CharField(max_length=45)
class Animal(Model):
name = models.CharField(max_length=45)
codename = models.CharField(max_length=45)
categories = models.ManyToManyField(Category)
serializers.py
class CategorySerializer(serializers.ModelSerializer):
class Meta:
model = models.Category
fields = '__all__'
class AnimalSerializer(serializers.ModelSerializer):
codename = serializers.HiddenField(default="auto_replace_me")
class Meta:
model = models.Animal
fields = '__all__'
views.py
class CategoryViewSet(ModelViewSet):
queryset = models.Category.objects.all()
serializer_class = serializers.CategorySerializer
class AnimalViewSet(ModelViewSet, CreateModelMixin):
queryset = models.Animal.objects.all()
serializer_class = serializers.AnimalSerializer
def create(self, request, *args, **kwargs):
codename = generate_codename()
# (1) external API request (with codename included on request) and returns a boolean `result`
if result:
# will call create method from parent class BUT
# (2) it needs to save the codename in database
return super(AnimalViewSet, self).create(request, *args, **kwargs)
else:
return HttpResponseServerError()
def generate_codename():
return ''.join([random.choice(string.ascii_letters) for n in range(10)])

Answer 1

Following code should do the job:
class AnimalViewSet(ModelViewSet, CreateModelMixin):
queryset = models.Animal.objects.all()
serializer_class = serializers.AnimalSerializer
def perform_create(serializer, codename):
serializer.save(codename=codename)
def create_with_codename(self, request, codename, *args, **kwargs):
# this is almost the same as CreateModelMixin 'create'
# but with one change: passing codename to 'perform_create' method
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
instance = self.perform_create(serializer, codename)
headers = self.get_success_headers(serializer.data)
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
def create(self, request, *args, **kwargs):
codename = generate_codename()
# (1) external API request (with codename included on request) and returns a boolean `result`
if result:
# will call create method from parent class BUT
# (2) it needs to save the codename in database
return self.create_with_codename(request, codename, *args, **kwargs)
else:
return HttpResponseServerError()
So basically, you should write your own function create_with_codename to change default behaviour of CreateModelMixin def create(self, request, *args, **kwargs)
Most important thing was to pass codename argument to perform_create. According to docs, everytime when you need to save serializer with appending additional values to it, you should use serializer.save(extra_field=extra_value)

Answer 2

After learn from you guys, I got this solution (only changing views.py):
views.py
class CategoryViewSet(ModelViewSet):
queryset = models.Category.objects.all()
serializer_class = serializers.CategorySerializer
class AnimalViewSet(ModelViewSet, CreateModelMixin):
queryset = models.Animal.objects.all()
serializer_class = serializers.AnimalSerializer
codename = None
def perform_create(self, serializer):
serializer.save(codename=self.codename)
def create(self, request, *args, **kwargs):
self.codename = generate_codename()
# (1) external API request (with codename included on request) and returns a boolean `result`
if result:
# will call create method from parent class BUT
# (2) it needs to save the codename in database
return super(AnimalViewSet, self).create(request, *args, **kwargs)
else:
return HttpResponseServerError()
def generate_codename():
return ''.join([random.choice(string.ascii_letters) for n in range(10)])