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Python Django Forms Inlines and Media Inline Model Formset

David Axelrod
David Axelrod
36,073 Points
Posted by David Axelrod
David Axelrod
36,073 Points

double form creation

would it effect django's route performance if we put the blank form logic after the request.post check? If it's posted then the server shouldn't have to create the blank forms. unless those forms are necessary. Thoughts?

something like this

From this

def quiz_create(request, course_pk):
  course = get_object_or_404(models.Course, pk = course_pk)
  form = forms.QuizForm()

  if request.method == 'POST':
    form = forms.QuizForm(request.POST)
    if form.is_valid():
      quiz = form.save(commit=False) # dont put into db
      quiz.course = course
      quiz.save()
      messages.add_message(request, messages.SUCCESS, "Quiz added!!!")
      return HttpResponseRedirect(quiz.get_absolute_url())
  return render(request, 'courses/quiz_form.html',{'form': form})

To this

def quiz_create(request, course_pk):
  #moved course into post logic
  #form is right before render()

  if request.method == 'POST':
    form = forms.QuizForm(request.POST)
    if form.is_valid():
      quiz = form.save(commit=False) # dont put into db
      course = get_object_or_404(models.Course, pk = course_pk)
      quiz.course = course
      quiz.save()
      messages.add_message(request, messages.SUCCESS, "Quiz added!!!")
      return HttpResponseRedirect(quiz.get_absolute_url())
  form = forms.QuizForm()
  return render(request, 'courses/quiz_form.html',{'form': form})

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,457 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,457 Points

In the original flow, if the posted form is not valid, form will be left set to the posted form values when the page is rendered in the return statement. This gives the user feedback on what failed during validation.

In your proposed flow, if the form is not valid, the form is reset before the render statement losing the user's entered data.

It might work if the form reset was in an else block:

def quiz_create(request, course_pk):
  #moved course into post logic
  #form is right before render()

  if request.method == 'POST':
    form = forms.QuizForm(request.POST)
    if form.is_valid():
      quiz = form.save(commit=False) # dont put into db
      course = get_object_or_404(models.Course, pk = course_pk)
      quiz.course = course
      quiz.save()
      messages.add_message(request, messages.SUCCESS, "Quiz added!!!")
      return HttpResponseRedirect(quiz.get_absolute_url())
  else:  # not POST
    form = forms.QuizForm()
  return render(request, 'courses/quiz_form.html',{'form': form})
David Axelrod
David Axelrod
36,073 Points
David Axelrod
David Axelrod
36,073 Points

Ahhh awesome! Thanks for the explanation