Django timezone fields don't accept all pytz timezones

Question

Django timezone fields are built upon pytz timezones, but some of the timezones of the latter are not valid for the fields. With a model like

from django.db import models
from timezone_field import TimeZoneField

class TestModel(models.Model):
    timezone_field = TimeZoneField(default='UTC')

def save(self, *args, **kwargs):
    self.clean()
    self.full_clean()
    super().save(*args, **kwargs)

If I run (in a shell)

import pytz
from models import TestModel

model = TestModel.objects.get(id=1)

for zone in pytz.all_timezones:
    model.timezone = zone
    model.save()

I get

django.core.exceptions.ValidationError: {'timezone': ["Value <DstTzInfo 'Africa/Asmera' LMT+2:27:00 STD> is not a valid choice."]}

So it fails first on 'Africa/Asmera' (it fails on others too, e.g. 'GMT+0').

Any idea of how to resolve this inconsistency? At the moment the user can select a timezone on the frontend that will give a backend error (the frontend is built in React and gets the timezones from moment timezone)

The choices are only the `common_timezones`, not `all_timezones`. — Willem Van Onsem, May 10 '18 at 10:26
Aha.. Any idea how to get `common_timezones` into javascript? (Apart from printing them and saving in a file that is)? Also, if you write it as an answer I'll accept — jorgen, May 10 '18 at 10:35
How do you now obtain the timezones in JavaScript? The package has support for form fields, and those are - as far as I know - `common_timezones` as well. — Willem Van Onsem, May 10 '18 at 10:35
I get them from moment timezone: https://momentjs.com/timezone/ — jorgen, May 10 '18 at 10:37
well the package has functionality for a form field. So you can use the attached formfield. — Willem Van Onsem, May 10 '18 at 10:38

score 4 · Accepted Answer · answered May 10 '18 at 10:36

As Willem mentioned in V1.2 of Django Timezone Fields, they changed the field's default choices from all_timezones to common_timezones. You can revert this change by explicitly setting the choices attribute in the field definition.

https://github.com/mfogel/django-timezone-field

1.2 (2015-02-05) For form field, changed default list of accepted timezones from pytz.all_timezones to pytz.common_timezones, to match DB field behavior. 1.1 (2014-10-05) Django 1.7 compatibility Added support for formating choices kwarg as [[, ], ...], in addition to previous format of [[, ], ...]. Changed default list of accepted timezones from pytz.all_timezones to pytz.common_timezones. If you have timezones in your DB that are in pytz.all_timezones but not in pytz.common_timezones, this is a backward-incompatible change. Old behavior can be restored by specifying choices=[(tz, tz) for tz in pytz.all_timezones] in your model definition.

class TestModel(models.Model):
    timezone_field = TimeZoneField(default='UTC', choices=[(tz, tz) for tz in pytz.all_timezones])

There is a disclaimer about this being a backwards incompatible change; so I urge you to look into this further

Django timezone fields don't accept all pytz timezones

1 Answers1