Django View class keeps values

Question

A curiosity that has accompanied me for a long time in Django and I never managed to heal:

Next. Let’s say I have something like:

from django.shortcuts import render
from django.views import View

from pagina.models import Config

class BasicView(View):
  try:
    dados = {
      'email': Config.objects.get(variavel = 'email').valor,
    }
  except:
    dados = {}

class TelaView(BasicView):
  def get(self, request, **kwargs):
    self.template_name = 'base.html'
    return render(request, self.template_name, self.dados)

Then, in the base.html template, I would call {{email}} and Django would show the registration in the database.

Now, if I were to keep the server running and modify the email log in the database so that the new email appears in the template, it would be necessary to stop the server and run it again.

My question: Why this happens and how to get around this?

Answer 1

This is because when python will run a script it creates a kind of cache of the files involved (those files tralala.pyc or else the files that are inside the directory __pycache__). Therefore, it performs the import of information between files only once (when it runs), not every time the view is called.

This is a standard behavior of the language itself, if you need to provide this information dynamically (it will be changed from time to time), look for a way to store it in the database through an object and use some queryset to search for it.

Should it help, here has the documentation on querysets and here documentation on databases. In case I haven’t been completely clear, I hope I’ve at least helped.