ideallical/django-bitfield

A BitField extension for Django Models

django-bitfield

Provides a BitField like class (using a BigIntegerField) for your Django models.

(If you're upgrading from a version before 1.2 the API has changed greatly and is backwards incompatible!)

Requirements

• Django >= 1.4
• PostgreSQL (see notes)

Notes:

• SQLite does not support save operations using a Bit (per the example under Usage).
• MySQL fails on most queries related to BitField's.

Installation

Install it with pip (or easy_install):

pip install django-bitfield

Usage

First you'll need to attach a BitField to your class. This acts as a BigIntegerField (BIGINT) in your database:

from bitfield import BitField

class MyModel(models.Model):
    flags = BitField(flags=(
        'awesome_flag',
        'flaggy_foo',
        'baz_bar',
    ))

Flags can also be defined with labels:

class MyModel(models.Model):
    flags = BitField(flags=(
        ('awesome_flag', 'Awesome Flag!'),
        ('flaggy_foo', 'Flaggy Foo'),
        ('baz_bar', 'Baz (bar)'),
    ))

Now you can use the field using very familiar Django operations:

# Create the model
o = MyModel.objects.create(flags=0)

# Add awesome_flag (does not work in SQLite)
MyModel.objects.filter(pk=o.pk).update(flags=F('flags').bitor(MyModel.flags.awesome_flag))

# Set flags manually to [awesome_flag, flaggy_foo]
MyModel.objects.filter(pk=o.pk).update(flags=MyModel.flags.awesome_flag | MyModel.flags.flaggy_foo)

# Remove awesome_flag (does not work in SQLite)
MyModel.objects.filter(pk=o.pk).update(flags=F('flags').bitand(~MyModel.flags.awesome_flag))

# Find by awesome_flag
MyModel.objects.filter(flags=MyModel.flags.awesome_flag)

# Exclude by awesome_flag
MyModel.objects.filter(flags=~MyModel.flags.awesome_flag)

# Test awesome_flag
if o.flags.awesome_flag:
    print "Happy times!"

# List all flags on the field
for f in o.flags:
    print f

# Get a flag label
print o.flags.get_label('awesome_flag')

Enjoy!

Admin

To use the widget in the admin, you'll need to update your ModelAdmin. Add the following lines to your ModelAdmin:

formfield_overrides = {
        BitField: {'widget': BitFieldCheckboxSelectMultiple},
}

Make sure you've imported the classes by adding these lines to the top of the file:

from bitfield import BitField
from bitfield.forms import BitFieldCheckboxSelectMultiple

There is also a BitFieldListFilter list filter (Django 1.4 or newer). To use it set list_filter ModelAdmin option:

list_filter = (
        ('flags', BitFieldListFilter,)
        )

BitFieldListFilter is in bitfield.admin module:

from bitfield.admin import BitFieldListFilter