Django: One function, two class-based views

Question

I am currently struggling to find a better solution for get_survey_state(self, context). It is in both CBVs and I think there is a better solution than mine. Can you advise me on that?

views.py

class SurveyExpectations(AdminPermissionRequiredMixin, TemplateView):
    template_name = 'admin/surveys/expectations.html'

    def get_survey_state(self, context):
        survey = self.request.event.surveys.active_pre_event().first()
        answers = Answer.objects.filter(question__survey=survey).exists()
        context['survey_is_active'] = survey
        context['answers_exist'] = answers

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        self.get_survey_state(context)
        context['questions_and_answers'] = self.request.event.surveys.get_results(
            settings.SURVEY_PRE_EVENT
        )
        return context

class SurveyFeedback(AdminPermissionRequiredMixin, TemplateView):
    template_name = 'admin/surveys/feedback.html'

    def get_net_promoter_score(self) -> float:
        [...]
        return netpromoterscore(scores)

    def get_average_age(self) -> int:
        [...]
        return int(answers['avg']) if answers['avg'] else None

    def get_survey_state(self, context):
        survey = self.request.event.surveys.active_post_event().first()
        answers = Answer.objects.filter(question__survey=survey).exists()
        context['survey_is_active'] = survey
        context['answers_exist'] = answers

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        self.get_survey_state(context)
        context['questions_and_answers'] = self.request.event.surveys.get_results(
            settings.SURVEY_POST_EVENT
        )
        context['netpromoterscore'] = self.get_net_promoter_score()
        context['average_age'] = self.get_average_age()
        return context

models.py

class SurveyQuerySet(models.QuerySet):
    def active_pre_event(self):
        return self.filter(is_active=True, template=settings.SURVEY_PRE_EVENT)

    def active_post_event(self):
        return self.filter(is_active=True, template=settings.SURVEY_POST_EVENT)

    def get_results(self, template):
        return (
            self.get(template=template)
            .questions.exclude(focus=QuestionFocus.EMAIL)
            .all()
            .prefetch_related('answers')
        )

class Survey(TimeStampedModel):
    id = models.UUIDField([...])
    is_active = models.BooleanField([...])
    template = models.CharField([...])

    objects = SurveyQuerySet.as_manager()

H4kor · Accepted Answer · 2019-09-07 09:23:54Z

1

You can use class inheritance. You create a Base Class (derived from TemplateView) in which you define all your common functionalities.

Then you can derive further views from the base class, which will inherit all functionality.

The get_survey_state uses the method self.get_survey() to allow using different retrieval methods in the derived views.

class BaseSurveyView(TemplateView):
    def get_survey_state(self, context):
        survey = self.get_survey()
        answers = Answer.objects.filter(question__survey=survey).exists()
        context['survey_is_active'] = survey
        context['answers_exist'] = answers

    def get_survey(self):
        raise NotImplementedError


class SurveyExpectations(AdminPermissionRequiredMixin, BaseSurveyView):
    template_name = 'admin/surveys/expectations.html'

    def get_survey(self):
        return self.request.event.surveys.active_pre_event().first()

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        self.get_survey_state(context)
        context['questions_and_answers'] = self.request.event.surveys.get_results(
            settings.SURVEY_PRE_EVENT
        )
        return context

class SurveyFeedback(AdminPermissionRequiredMixin, BaseSurveyView):
    template_name = 'admin/surveys/feedback.html'

    def get_survey(self):
        return self.request.event.surveys.active_post_event().first()

    def get_net_promoter_score(self) -> float:
        [...]
        return netpromoterscore(scores)

    def get_average_age(self) -> int:
        [...]
        return int(answers['avg']) if answers['avg'] else None

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        self.get_survey_state(context)
        context['questions_and_answers'] = self.request.event.surveys.get_results(
            settings.SURVEY_POST_EVENT
        )
        context['netpromoterscore'] = self.get_net_promoter_score()
        context['average_age'] = self.get_average_age()
        return context

edited Sep 7, 2019 at 9:23

answered Sep 7, 2019 at 9:03

H4kor

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5 Comments

Joey Coder Over a year ago

Did you see the two different filters? active_pre_event and active_post_event would still to be different. Is it possible to integrate that as well?

H4kor Over a year ago

They are part of the model how do they change? If you want to use different models you could do the same thing with the model and implement methods in the ChildViews that return the model to be used.

Joey Coder Over a year ago

active_pre_event filters for template=settings.SURVEY_PRE_EVENT) active_post_event filters for template=settings.SURVEY_POST_EVENT). That way I can display different answers from different surveys. The second part I didn't completely understand what you mean.

H4kor Over a year ago

Ahh ok. Now I know what you mean. I adjusted my answer. It uses a method implemented in the derived Views to get the correct survey.

Joey Coder Over a year ago

Ah, smart solution. Thank you. I like that!

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