Django: How to make form conditional?

Question

I have a form with two fields. The user should be required to only select one of the two. Not both and not none. I tried solving this by overwriting the clean method as described in the Django Doc:

forms.py

class ConfigureWorkout(forms.Form):
    first_exercise = forms.ModelChoiceField(empty_label="select", label="Choose First Exercise", queryset=FirstExercise.objects.all(), required=False) 
    sec_exercise = forms.ModelChoiceField(empty_label="select", label="Choose Sec Exercise", queryset=SecExercise.objects.all(), required=False)

    def clean(self):
        first_exercise = self.cleaned_data.get("first_exercise")
        sec_exercise = self.cleaned_data.get("sec_exercise")

        if first_exercise and sec_exercise:
            raise forms.ValidationError("Enter either a First Exercise or a Secondary Exercise.")
        else:
            return self.cleaned_data

views.py

def configure(request):
    configure_workout = ConfigureWorkout()

    if request.method == "GET":
        return render(request, "userprofile/some.html", configure_workout)

    else:
        return render(request, "app/other.html")

template

<form action="{% url 'configure' %}" method="POST">
    {% csrf_token %}
    {{ configure_workout }}
    <input type="submit" name="configuration_completed">
</form>

However, if I test this by selecting both fields in the form, there won't be an error displayed/raised. I pass the form successfully and get sent to "other.html".

What am I missing? Thanks so much in advance for any help:)

Answer 1

It seems you're not passing actual data to your form. Maybe this will help:

def configure(request):
    configure_workout = ConfigureWorkout()

    if request.method == "GET":
        return render(request, "userprofile/some.html", configure_workout)

    else:
        configure_workout = ConfigureWorkout(request.POST)
        configure_workout.is_valid()
        configure_workout.clean()
        return render(request, "app/other.html")

Answer 2

Building on @trafalinos answer and looking at the documentation on Forms , I would suggest doing the following:

In forms.py :

class ConfigureWorkout(forms.Form):
    first_exercise = forms.ModelChoiceField(empty_label="select", label="Choose First Exercise", queryset=FirstExercise.objects.all(), required=False) 
    sec_exercise = forms.ModelChoiceField(empty_label="select", label="Choose Sec Exercise", queryset=SecExercise.objects.all(), required=False)

    def clean(self):
        cleaned_data = super().clean()  # compare documentation
        first_exercise = cleaned_data.get("first_exercise")
        sec_exercise = cleaned_data.get("sec_exercise")

        if first_exercise and sec_exercise:
            raise forms.ValidationError("Enter either a First Exercise or a Secondary Exercise.")
        else:
            return self.cleaned_data

And (credits to trafalino) in views.py :

def configure(request):
    if request.method == "GET":
        configure_workout = ConfigureWorkout()
        return render(request, "userprofile/some.html", configure_workout)

    else:
        configure_workout = ConfigureWorkout(request.POST)
        configure_workout.clean()
        return render(request, "app/other.html")