Django2 How can i make some conditions in my Class based View

Question

please i have an issue , i want to check the difference between two dates from my form, then allows to create the object using my class based_View if the date is bigger than an other attribute, if not render it to an other page without inserting nothing in the database.here is my

    # view  
class AddVacation(LoginRequiredMixin, CreateView):
    form_class = VacationCreateForm
    template_name = 'vacation.html'
    login_url = 'login'

    def form_valid(self, form):
        instance = form.save(commit=False)
        instance.employee = self.request.user
        return super(AddVacation, self).form_valid(form)

    # form:  
class VacationCreateForm(forms.ModelForm):

    class Meta:
        model = VacationModel
        fields = [
        'type',
        'startDate',
        'enddate',
        ]

Answer 1

class VacationCreateForm(forms.ModelForm):
    class Meta:
        model = VacationModel
        fields = [
            'type',
            'startDate',
            'enddate',
        ]
    def clean(self):
        start_date = self.cleaned_data['start_date']
        end_date = self.cleaned_data['end_date']
        from dateutils import parse
        start_date = parse(start_date)
        end_date = parse(end_date)
        # make your calculations
        raise forms.ValidationError("message.")

class AddVacation(LoginRequiredMixin, CreateView):
    form_class = VacationCreateForm
    template_name = 'vavcation.html'
    login_url = 'login'

    def post(self, request, *args, **kwargs):
        """
        Handles POST requests, instantiating a form instance with the passed
        POST variables and then checked for validity.
        """
        form = self.get_form()
        if form.is_valid():
            return self.form_valid(form)
        else:
            redirect(to_ur_another_view)

I'm not solving your specific problem I just deliver the idea or what can you do to jump over your problem

Answer 2

I found this solution to check the delay ! i was thinking class basedView are always the best

def create_vacation(request):
        form = VacationCreateForm(request.POST or None)
        error_message = ""
        if form.is_valid():
            dateD = request.POST.get("Startdate")
            dateF = request.POST.get("Enddate")
            fmt = '%Y-%m-%d'
            dS = datetime.strptime(str(dateS), fmt)
            dE = datetime.strptime(str(dateE), fmt)
            dateDiff = (dE - dS).days
            q = Employee.objects.get(id__iexact=request.user.id)
            if dateDiff < q.VacationDays:
                instance = form.save(commit=False)
                instance.employee = request.user
                instance.save()
            else:
                error_message = "Impossible check Your demand"
        context = {
            "form": form,
            "error_message": error_message,
        }
        return render(request, 'vacation.html', context)