Share choices across Django apps

Question

In my models I'm using the choices option in some of my fields. But I'm using the same choices in multiple apps in my Django project.

Where should I place my choices and how can I load these choices in all my apps?

Answer 1

We usually have quite a few project-specific apps per project here, and to try and keep dependencies reasonably clean we usually have two more apps:

• "core" in which we put things shared by other apps (any app can depend on "core", "core" doesn't depend on any app),

• and "main" in which tie things together ("main" can depend on any app, no app is allowed to depend on "main").

In your case, these shared choices would belong to core.models.

Answer 2

I like to put all the constants in a file called constants.py inside each app. When we want some kind of global choices shared between the apps, we put them in a "core" app (like @bruno desthuilliers described) and import them when needed.

Example:

constants.py

# -*- coding: utf-8 -*-

STATE_1 = 0
STATE_2 = 1
STATE_3 = 2

STATE_CHOICES = (
    (STATE_1, 'STATE 1'),
    (STATE_2, 'STATE 2'),
    (STATE_3, 'STATE 3')
)

any_app/models.py

from django.db import models
from other.app.models import User
from core.constants import SOME_OTHER_CHOICES
from core.constants import STATE_1_REAL
from .constants import STATE_CHOICES
from .constants import STATE_1



class ModelX(models.Model):
    user = models.ForeignKey(User)
    state = models.IntegerField(verbose_name=u'state', 
                                choices=STATE_CHOICES, 
                                default=STATE_1)
    core_state = models.IntegerField(verbose_name=u'real state', 
                                     choices=SOME_OTHER_CHOICES, 
                                     default=STATE_1_REAL)

    class Meta:
        ordering = ('-state',)