django-datetime-utc 1.0.0

Django UTC datetime model field - timestamp without time zone

django-datetime-utc provides DateTimeUTCField, a naive datetime model field. In PostgreSQL this translates to the field timestamp without time zone. All timestamps are saved in UTC.

Why use this?

The problem with using Django’s DateTimeField is unless the default timezone on your (PostgreSQL) database server is set to UTC it doesn’t matter which TZ settings you select in Django, PostgreSQL will save all timestamps in local time with an offset.

Features

• Supports the default DateTimeField options such as auto_now_add and auto_now

• Works with South

• Saves all timestamps in UTC

• Values automatically converted to local time (specified by TIME_ZONE in your project settings.py) in forms and templates

Install

From PyPi:

$ pip install django-datetime-utc

In settings.py add datetimeutc to the list of installed apps, set your local time zone and ensure time zone support is enabled:

TIME_ZONE = 'Europe/London'
USE_TZ = True
INSTALLED_APPS = (
    #...
    'datetimeutc',
)

Usage

In models.py:

from django.db import models
from datetimeutc.fields import DateTimeUTCField

class Stuff(models.Model):
    title = models.CharField(max_length=100)
    stuff_time = DateTimeUTCField()
    submitted = DateTimeUTCField(auto_now_add=True)

Notes

If your code creates datetime objects, they should always be TZ aware so they are automatically converted correctly to UTC (if necessary) before being saved to the database. Using the Stuff model above as an example, to set stuff_time correctly you would:

import datetime
from dateutil import tz

utcnow = datetime.datetime.utcnow().replace(tzinfo=tz.gettz('UTC'))
Stuff.objects.create(title='My stuff', stuff_time=utcnow)

This also goes for user defined datetime objects. For example in the admin panel, if the user submits a value for stuff_time, in admin.py you would:

from dateutil import tz
from django.contrib import admin
from django.conf import settings
from stuff.models import Stuff


class StuffAdmin(admin.ModelAdmin):
    def save_model(self, request, obj, form, change):
        obj.stuff_time = obj.stuff_time.replace(
            tzinfo=tz.gettz(settings.TIME_ZONE))
        obj.save()

admin.site.register(Stuff, StuffAdmin)

Here the datetime object is made TZ aware by setting the time zone to the one specified in settings.py (presumably the time zone of the user entering this data). This will be converted to UTC prior to save automatically.