django-timezone-utils¶
Adds automatic time zone conversions and support utilities to Django.
Contents¶
Setup¶
Installation¶
Install from PyPi with pip:
pip install django-timezone-utils
To use django-timezone-utils in your Django project, just import and use the utility classes described in this documentation; there is no need to modify your INSTALLED_APPS setting.
Dependencies¶
Deprecation Policy¶
django-timezone-utils will support any version of Django that is currently supported by the Django Software Foundation. Please view Django’s Supported Version documentation for more information.
Fields¶
Contains timezone-related fields.
TimeZoneField¶
- class TimeZoneField(*args, **kwargs)¶
A models.CharField subclass that stores a valid Olson Timezone string found in pytz.all_timezones to the database.
Raises django.core.exceptions.ValidationError: if the value is not a valid Olson Time zone string. Returns: A datetime.tzinfo object based on the value or None. Return type: datetime.tzinfo
from timezone_utils.fields import TimeZoneField
from timezone_utils.choices import PRETTY_ALL_TIMEZONES_CHOICES
class Location(models.Model):
# ...
timezone = TimeZoneField(choices=PRETTY_ALL_TIMEZONES_CHOICES)
You can pass a default Olson timezone value to the model as a string:
from timezone_utils.fields import TimeZoneField
class Location(models.Model):
# ...
timezone = TimeZoneField(default='US/Pacific')
You can also pass a default Olson timezone value to the model as a pytz.timezone instance:
import pytz
from timezone_utils.fields import TimeZoneField
class Location(models.Model):
# ...
timezone = TimeZoneField(default=pytz.timezone('US/Eastern'))
Accessing a TimeZoneField on a model¶
As a convenience, TimeZoneField automatically converts its model instance attribute representation to a pytz.timezone instance:
>>> from datetime import datetime
>>> from django.utils.timezone import make_aware
>>> from app_label.models import Location
>>> location = Location.objects.create(timezone='US/Eastern')
>>> print(location.timezone)
<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>
>>> unaware_dt = datetime(2015, 1, 1)
>>> aware_dt = make_aware(unaware_dt, location.timezone)
>>> print(aware_dt)
datetime.datetime(2015, 1, 1, 0, 0, tzinfo=<DstTzInfo 'US/Eastern' EST-1 day, 19:00:00 STD>)
LinkedTZDateTimeField¶
- class LinkedTZDateTimeField(populate_from=None, time_override=None, *args, **kwargs)¶
A models.DateTimeField subclass that will automatically save a datetime object as a particular time zone as declared in the kwarg populate_from. You can also override the time each time the object is saved with the kwarg time_override, which must be a datetime.time instance.
Parameters: - populate_from – The location of the field which contains the time zone that will be used for this field. Must be either a function which returns a models.ForeignKey path to the timezone or a string (if the timezone field is located on the model).
- time_override – Automatically overrides the time value each time the object is saved to the time that is declared. Must be a datetime.time instance.
Raises: - AttributeError – if the populate_from parameter is invalid.
- ValueError – if the time_override is not a datetime.time instance.
- pytz.UnknownTimeZoneError – if the parsed model instance value of populate_from is not a valid Olson time zone string.
Returns: A datetime.datetime object based on the time zone declared in populate_from and override from time_override or None.
Return type:
Note
If auto_now or auto_now_add is declared, the value of time_override is ignored.
Caution
Django cannot serialize lambdas! If you provide a lambda for populate_from, your model will fail to migrate in Django 1.7+.
from datetime import datetime
from timezone_utils.fields import LinkedTZDateTimeField, TimeZoneField
from timezone_utils.choices import PRETTY_ALL_TIMEZONES_CHOICES
class Location(models.Model):
# ...
timezone = TimeZoneField(choices=PRETTY_ALL_TIMEZONES_CHOICES)
def get_location_timezone(obj):
return obj.location.timezone
class LocationReport(models.Model):
# ...
location = models.ForeignKey('app_label.Location', related_name='reports')
timestamp = LinkedTZDateTimeField(populate_from=get_location_timezone)
class LocationPeriod(models.Model):
# ...
location = models.ForeignKey('app_label.Location', related_name='reports')
start = LinkedTZDateTimeField(
populate_from=get_location_timezone,
time_override=datetime.min.time()
)
end = LinkedTZDateTimeField(
populate_from=get_location_timezone,
time_override=datetime.max.time()
)
Accessing a LinkedTZDateTimeField on a model¶
As a convenience, LinkedTZDateTimeField automatically converts its model instance attribute representation to the time zone declared in the populate_from, regardless of what settings.TIME_ZONE is set to:
>>> from datetime import datetime
>>> from app_label.models import LocationPeriod
>>> location = location.objects.get(pk=1)
>>> location_period = LocationPeriod.objects.create(location=location, start=datetime(2015, 1, 1), end=datetime(2015, 12, 31))
>>> print(location_period.start)
datetime.datetime(2015, 1, 1, 0, 0, tzinfo=<DstTzInfo 'US/Eastern' EST-1 day, 19:00:00 STD>)
>>> print(location_period.end)
datetime.datetime(2015, 12, 31, 23, 59, 59, 999999, tzinfo=<DstTzInfo 'US/Eastern' EST-1 day, 19:00:00 STD>)
Accessing a LinkedTZDateTimeField in templates¶
Django templates will automatically cast the timezones to the currently-activated time zone for the user viewing the page. An example of how to display our fields with the appropriate time zone would look something like this:
app_label/views.py:
# Django
from django.views.generic import ListView
# App
from app_label.models import LocationPeriod
class LocationReportingPeriodListView(ListView):
model = LocationPeriod
template_name = 'app_label/location_period_list.html'
def get_queryset(self):
"""Retrieve the queryset and perform select_related on `location` since
we will be using it in the template.
"""
return super(
LocationReportingPeriodListView,
self
).get_queryset().select_related(
'location'
)
templates/app_label/location_period_list.html:
{% load tz %}
{% load i18n %}
{% block content %}
<table>
<thead>
<tr>
<th>{% trans "Location" %}</th>
<th>{% trans "Start" %}</th>
<th>{% trans "End" %}</th>
</tr>
</thead>
<tdata>
{% for period in object_list %}
{# Activate the timezone for each location #}
{% timezone period.location.timezone %}
<tr>
<td>{{ period.location.name }}</td>
<td>{{ period.start }}</td>
<td>{{ period.end }}</td>
</tr>
{% endtimezone %}
{% empty %}
<tr>
<td colspan=3>{% trans "No periods to display." %}</td>
</tr>
{% endfor %}
</tdata>
</table>
{% endblock content %}
Choices¶
Contains constants and functions to generate model/form choices for time zones.
ALL_TIMEZONES_CHOICES¶
- ALL_TIMEZONE_CHOICES¶
Returns choices directly populated from pytz.all_timezones.
>>> from timezone_utils.choices import ALL_TIMEZONES_CHOICES
>>> print ALL_TIMEZONES_CHOICES
(
('Africa/Abidjan', 'Africa/Abidjan'),
('Africa/Accra', 'Africa/Accra'),
('Africa/Addis_Ababa', 'Africa/Addis_Ababa'),
('Africa/Algiers', 'Africa/Algiers'),
('Africa/Asmara', 'Africa/Asmara'),
('Africa/Asmera', 'Africa/Asmera'),
('Africa/Bamako', 'Africa/Bamako'),
('Africa/Bangui', 'Africa/Bangui'),
('Africa/Banjul', 'Africa/Banjul'),
('Africa/Bissau', 'Africa/Bissau'),
...
)
COMMON_TIMEZONES_CHOICES¶
- COMMON_TIMEZONE_CHOICES¶
Returns choices directly populated from pytz.common_timezones.
>>> from timezone_utils.choices import COMMON_TIMEZONES_CHOICES
>>> print COMMON_TIMEZONES_CHOICES
(
('Africa/Abidjan', 'Africa/Abidjan'),
('Africa/Accra', 'Africa/Accra'),
('Africa/Addis_Ababa', 'Africa/Addis_Ababa'),
('Africa/Algiers', 'Africa/Algiers'),
('Africa/Asmara', 'Africa/Asmara'),
('Africa/Bamako', 'Africa/Bamako'),
('Africa/Bangui', 'Africa/Bangui'),
('Africa/Banjul', 'Africa/Banjul'),
('Africa/Bissau', 'Africa/Bissau'),
('Africa/Blantyre', 'Africa/Blantyre'),
...
)
PRETTY_ALL_TIMEZONES_CHOICES¶
- PRETTY_ALL_TIMEZONES_CHOICES¶
Returns choices formatted for display ordered by their timezone offsets populated from pytz.all_timezones.
>>> from timezone_utils.choices import PRETTY_ALL_TIMEZONES_CHOICES
>>> print PRETTY_ALL_TIMEZONES_CHOICES
(
('Etc/GMT+12', '(GMT-12:00) Etc/GMT+12'),
('Etc/GMT+11', '(GMT-11:00) Etc/GMT+11'),
('Pacific/Midway', '(GMT-11:00) Pacific/Midway'),
('Pacific/Niue', '(GMT-11:00) Pacific/Niue'),
('Pacific/Pago_Pago', '(GMT-11:00) Pacific/Pago_Pago'),
('Pacific/Samoa', '(GMT-11:00) Pacific/Samoa'),
('US/Samoa', '(GMT-11:00) US/Samoa'),
('America/Adak', '(GMT-10:00) America/Adak'),
('America/Atka', '(GMT-10:00) America/Atka'),
('Etc/GMT+10', '(GMT-10:00) Etc/GMT+10'),
...
)
PRETTY_COMMON_TIMEZONES_CHOICES¶
- PRETTY_COMMON_TIMEZONES_CHOICES¶
Returns choices formatted for display ordered by their timezone offsets populated from pytz.common_timezones.
>>> from timezone_utils.choices import PRETTY_COMMON_TIMEZONES_CHOICES
>>> print PRETTY_COMMON_TIMEZONES_CHOICES
(
('Pacific/Midway', '(GMT-11:00) Pacific/Midway'),
('Pacific/Niue', '(GMT-11:00) Pacific/Niue'),
('Pacific/Pago_Pago', '(GMT-11:00) Pacific/Pago_Pago'),
('America/Adak', '(GMT-10:00) America/Adak'),
('Pacific/Honolulu', '(GMT-10:00) Pacific/Honolulu'),
('Pacific/Johnston', '(GMT-10:00) Pacific/Johnston'),
('Pacific/Rarotonga', '(GMT-10:00) Pacific/Rarotonga'),
('Pacific/Tahiti', '(GMT-10:00) Pacific/Tahiti'),
('US/Hawaii', '(GMT-10:00) US/Hawaii'),
('Pacific/Marquesas', '(GMT-09:30) Pacific/Marquesas'),
...
)
get_choices(timezones)¶
- get_choices(timezones)¶
Retrieves timezone choices from any iterable (normally from pytz).
Parameters: timezones (iterable) – Any iterable that contains valid Olson Time Zone strings.
Returns: A tuple containing tuples of time zone choices.
Return type: tuple
Raises: - pytz.exceptions.UnknownTimeZoneError – if the string from the iterable timezones parameter is not recognized as a valid Olson time zone.
- TypeError – if the timezones parameter is not iterable.
Using get_choices(timezones) for custom time zone choices¶
If you want to limit choices to a particular country (as an example), you could do this:
>>> import pytz
>>> from timezone_utils.choices import get_choices
>>> choices = get_choices(pytz.country_timezones('US'))
>>> print choices
(
(u'America/Adak', '(GMT-10:00) America/Adak'),
(u'Pacific/Honolulu', '(GMT-10:00) Pacific/Honolulu'),
(u'America/Anchorage', '(GMT-09:00) America/Anchorage'),
(u'America/Juneau', '(GMT-09:00) America/Juneau'),
(u'America/Nome', '(GMT-09:00) America/Nome'),
(u'America/Sitka', '(GMT-09:00) America/Sitka'),
(u'America/Yakutat', '(GMT-09:00) America/Yakutat'),
(u'America/Los_Angeles', '(GMT-08:00) America/Los_Angeles'),
(u'America/Metlakatla', '(GMT-08:00) America/Metlakatla'),
(u'America/Boise', '(GMT-07:00) America/Boise'),
(u'America/Denver', '(GMT-07:00) America/Denver'),
...
)
Contributing¶
Please file bugs and send pull requests to the GitHub repository and issue tracker.