Shortcuts

This is a collection of Django-styled shotcut function.

chamber.shortcuts.get_object_or_none(klass, *args, **kwargs)

Takes a Model or a QuerySet and some filter keyword arguments and returns an instance of the Model if it exists, None otherwise. Similar to get_object_or_404 in Django.

>>> get_object_or_none(User, pk=1)
<User: Gaul Asterix>
>>> get_object_or_none(User.objects.exclude(pk=1), pk=1) or ''

chamber.shortcuts.get_object_or_404(klass, *args, **kwargs)

Takes a Model or a QuerySet and some filter keyword arguments and returns an instance of the Model if it exists, raises django.http.response.Http404 otherwise.

>>> get_object_or_404(User, pk=1)
<User: Gaul Asterix>
>>> get_object_or_404(User.objects.exclude(pk=1), pk=1)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/var/ve/lib/python2.7/site-packages/chamber/shortcuts.py", line 21, in get_object_or_404
    raise Http404
Http404

chamber.shortcuts.distinct_field(klass, *args, **kwargs)

Takes a Model or a QuerySet. The rest of the args are the fields whose unique values should be returned.

>>> User.objects.filter(last_name='Gaul')
[<User: Gaul Obelix>, <User: Gaul Asterix>]
>>> distinct_field(User.objects.filter(last_name='Gaul'), 'last_name')
[(u'Gaul',)]

chamber.shortcuts.filter_or_exclude_by_date(negate, klass, **kwargs)

Takes a bool (True for exclude, False for filter), Model or QuerySet and date parameters and return queryset filtered or excluded by these date parameters.

>>> Order.objects.values_list('created_at', flat=True)
[datetime.datetime(2014, 4, 6, 15, 56, 16, 727000, tzinfo=<UTC>),
 datetime.datetime(2014, 2, 6, 15, 56, 16, 727000, tzinfo=<UTC>),
 datetime.datetime(2014, 1, 11, 23, 15, 43, 727000, tzinfo=<UTC>)]
>>> filter_or_exclude_by_date(False, Order, created_at=date(2014, 2, 6))
[<Order: MI-1234567>]
>>> filter_or_exclude_by_date(False, Order, created_at=date(2014, 2, 6))[0].created_at
datetime.datetime(2014, 2, 6, 15, 56, 16, 727000, tzinfo=<UTC>)

chamber.shortcuts.filter_by_date(klass, **kwargs)

Shortcut for chamber.shortcuts.filter_or_exclude_by_date with first parameter False.

chamber.shortcuts.exclude_by_date(klass, **kwargs)

Shortcut for chamber.shortcuts.filter_or_exclude_by_date with first parameter True.

chamber.shortcuts.change(obj, **changed_fields)

Helper for changing model instance fields without saving. All field names are validated if really exist.

>>> user = User.objects.get(last_name='Gaul')
>>> change(user, last_name='Goul')
>>> user.last_name
'Goul'
>>> user.refresh_from_db().last_name
'Gaul'

chamber.shortcuts.change_and_save(obj, update_only_changed_fields=False, **changed_fields)

Helper for changing model instance fields with saving. If you can update only really changed fields you can set update_only_changed_fields to True.

::

>>> user = User.objects.get(last_name='Gaul')
>>> change_and_save(user, last_name='Goul')
>>> user.last_name
'Goul'
>>> user.refresh_from_db().last_name
'Goul'

chamber.shortcuts.bulk_change(iterable, **changed_fields)

Changes model instances in the given iterable without saving.

::

>>> users = User.objects.filter(last_name='Gaul')
>>> bulk_change(users, last_name='Goul')
>>> all((user.last_name=='Goul' for user in users))
True
>>> all((user.refresh_from_db().last_name=='Goul' for user in users))
False

chamber.shortcuts.bulk_change_and_save(iterable, update_only_changed_fields=False, **changed_fields)

Change model instances in the given iterable with saving. If you want to update only really changed fields you can set update_only_changed_fields to True.

::

>>> users = User.objects.filter(last_name='Gaul')
>>> bulk_change_and_save(users, last_name='Goul')
>>> all((user.last_name=='Goul' for user in users))
True
>>> all((user.refresh_from_db().last_name=='Goul' for user in users))
True

chamber.shortcuts.bulk_save(iterable, update_only_changed_fields=False, **changed_fields)

Saves a objects in a given iterable.