django-chamber

This library contains useful functions and classes mainly for a web development with Django (form and model fields, shortcuts, advanced datastructure, decoraters etc.). For more details see examples below.

Reference

Forms

chamber.forms.fields.DecimalField

django.forms.DecimalField with step parameter and validated min and max parameters.

chamber.forms.widgets.ReadonlyWidget

Widget for safe rendering of readonly form values.

Models

chamber.models.fields.SouthMixin

Mixin for automatic South migration of custom model fields.

chamber.models.fields.DecimalField

django.db.models.DecimalField with step, min and max parameters. Uses chamber.forms.fields.DecimalField as default form field.

chamber.models.fields.RestrictedFileFieldMixin

Same as FileField, but you can specify:

• content_types - list containing allowed content_types. Example: ['application/pdf', 'image/jpeg']
• max_upload_size - a number indicating the maximum file size allowed for upload in MB. Maximum upload size can be specified in project settings under MAX_FILE_UPLOAD_SIZE constant

chamber.models.fields.FileField

django.db.models.FileField with RestrictedFileFieldMixin options.

chamber.models.fields.ImageField

sorl.thumbnail.ImageField (fallback to django.db.models.ImageField) with RestrictedFileFieldMixin options.

chamber.models.fields.CharNullField

django.db.models.CharField that stores NULL but returns ''.

Utils

chamber.utils.remove_accent

remove_accent('ěščřžýáíé') # 'escrzyaie'

chamber.utils.get_class_method

It returns a method of a given class or instance.

chamber.utils.datastructures.AbstractEnum

Base enumeration class with controlled __getattr__.

chamber.utils.datastructures.Enum

Python's set with AbstractEnum behaviour.

chamber.utils.datastructures.NumEnum

Python's dict with AbstractEnum behaviour.

>>> NumEnum('a', 'b')
{'a': 1, 'b': 2}

chamber.utils.datastructures.AbstractChoicesEnum

Base choices class (as used in Model field's choices argument).

chamber.utils.datastructures.ChoicesEnum

django.utils.datastructures.SortedDict with AbstractEnum and AbstractChoicesEnum behaviour. Useful for string based choices.

>>> enum = ChoicesEnum(('OK', 'ok'), ('KO', 'ko'))
>>> enum
{'OK': 'ok', 'KO': 'ko'}
>>> enum.OK
'ok'
>>> enum.choices
[('OK', 'ok'), ('KO', 'ko')]

chamber.utils.datastructures.ChoicesNumEnum

django.utils.datastructures.SortedDict with AbstractEnum and AbstractChoicesEnum behaviour. Useful for integer based choices.

>>> enum = ChoicesNumEnum(('OK', 'ok', 1), ('KO', 'ko', 2))
>>> enum.KO
2
>>> enum.choices
[(1, 'ok'), (2, 'ko')]
>>> enum.get_label(2)
'ko'

chamber.utils.decorators.classproperty

Ties property to class, usefull for usage in class methods.

class RestResource(BaseResource):
    @classproperty
    def csrf_exempt(cls):
        return not cls.login_required

    @classmethod
    def as_view(cls, allowed_methods=None, **initkwargs):
        view.csrf_exempt = cls.csrf_exempt

chamber.utils.decorators.singleton

Class decorator, which allows for only one instance of class to exist.

chamber.utils.decorators.short_description

Sets short_description attribute (this attribute is used by list_display and formulars).

@short_description('amount')
def absolute_amount(self):
    return abs(self.amount)

is equivalent of

def absolute_amount(self):
    return abs(self.amount)
absolute_amount.short_description = 'amount'

chamber.utils.forms.formset_has_file_field

Returns True if passed formset contains FileField (or ImageField).

chamber.utils.http.query_string_from_dict

Assemble query string from dict of parameters.

>>> query_string_from_dict({'q': 'query1', 'user': 'test'})
u'q=query1&user=test'

Shortcuts

chamber.shortcuts.get_object_or_none

Takes Model or QuerySet and arguments and returns instance of Model if exists, None otherwise.

>>> 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

Takes Model or QuerySet and arguments and returns instance of Model if 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

Takes Model or QuerySet and distinction parameters and returns list of unique values.

>>> 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

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

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

chamber.shortcuts.exclude_by_date

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

Development

For contribution go to example directory and call make install to install an example project.

Testing

To run tests go to example directory and call make test.

License

See LICENSE file.