Django UpdateView with related model - django

Question

I have the following situation and I don't know how to do an update:
#models.py
class Task(models.Model):
creation_date = models.DateField(
default=None,
)
name = models.CharField(
max_length=255,
)
description = models.TextField(
max_length=500,
blank=True,
null=True,
)
class TaskDetails(models.Model):
PEND = 1
COMP = 2
TASK_STATUS = (
(PEND, 'pending'),
(COMP, 'completed'),
)
task = models.OneToOneField(
Task,
primary_key=True,
on_delete=models.CASCADE
)
solution = models.CharField(
max_length=255,
)
due_date = models.DateField(
null=True,
default=None,
blank=True,
)
status = models.PositiveSmallIntegerField(
default=1,
choices=TASK_STATUS,
)
And now my view
#views.py
class TaskUpdate(UpdateView):
model = Task
second_model = TaskDetails
form_class = TaskForm
second_form_class = TaskDetailsForm
pk_url_kwarg = 'task_id'
def get_context_data(self, **kwargs):
context = super(TaskUpdate, self).get_context_data(**kwargs)
if self.request.method == 'POST':
details_form = self.second_form_class(self.request.POST, prefix='details')
else:
details_object = self.second_model.objects.get(pk=self.kwargs.get(self.pk_url_kwarg))
details_form = self.second_form_class(instance=details_object, prefix='details')
context['details_form'] = details_form
return context
def post(self, request, *args, **kwargs):
self.object = self.get_object()
form = self.form_class(request.POST)
details_form = self.second_form_class(request.POST, prefix='details')
if form.is_valid() and details_form.is_valid():
return self.form_valid(form, details_form)
else:
return self.form_invalid(form, details_form)
def form_valid(self, form, details_form):
form.instance.creation_date = datetime.now().date()
self.object = form.save()
details_form.instance.task = self.object
details_form.save()
return HttpResponseRedirect(self.success_url)
def form_invalid(self, form, details_form):
return self.render_to_response(self.get_context_data(form=form, details_form=details_form))
I also have the ModelForms: TaskForm and TaskDetailsForm. Not relevant here.
The 2 forms are displayed and submitted at once.
But instead of updating the existing record in Task and TaskDetails tables, it creates a new one in both tables
I think my problem is in form_valid. What should I put there?
Thanks a lot

Answer 1

In the post method forms are created without instance. You have to pass you instances there.
def post(self, request, *args, **kwargs):
# get current task
obj = self.get_object()
#initiate the task form with this object as instance
form = self.form_class(request.POST, instance=obj)
#get realted details object or None.
#I can't check if this string works, but it should.
details_obj = getattr(object, 'taskdetails', None)
#initiate the details_form with this details_object as instance
details_form = self.second_form_class(request.POST, prefix='details',
instance=details_obj)
if form.is_valid() and details_form.is_valid():
return self.form_valid(form, details_form)
else:
return self.form_invalid(form, details_form)
def form_valid(self, form, details_form):
#save object
obj = form.save(commit=False)
obj.creation_date = datetime.now().date()
obj.save()
#save details_object
details_obj = details_form.save(commit=False)
details_obj.task = obj
details_obj.save()
return HttpResponseRedirect(self.success_url)

Answer 2

I think this should work. You don't need the form_valid and form_invalid methods in this case,
def post(self, request, *args, **kwargs):
response = super(TaskUpdate, self).post(request, *args, **kwargs)
details_form = self.second_form_class(self.request.POST, prefix='details')
if details_form.is_valid():
task = self.get_object()
self.second_model.objects.filter(task=task)
.update(**details_form.cleaned_data)
return response
return render(request, self.template_name, {
'form': self.get_form(self.get_form_class()),
'details_form': details_form,
})
PS: put related_name=task_details for the OneToOneField and auto_now_add=True for the creation date of your task
Nevertheless, why don't you include the Task Details into task and stop using this OneToOneKey?