django-state-field

django-state-field is a reusable Django app, providing a custom field called StateField for changing states. It is a simple state machine for your app to limit state changes.

Installation

Install django-state-field with pip:

pip install django-state-field

or download tarball source file from github and extract it:

python setup.py install

Configuration

Add state_field to your settings.py's INSTALLED_APPS:

INSTALLED_APPS = (
    ...
    'state_field',
    ...
)

Usage

Define your model:

from django.db import models
from state_field.fields import StateField

flow = {
           'default_state': ['next_state', 'default_state'],
	       'next_state': ['previous_state', 'default_state']
	   }

class Book(models.Model):
    state = StateField(max_length=20, state_flow=flow)

Change states in your app:

>>> book = Book.objects.create(state='default_state')

# This is allowed
>>> book.state = 'next_state'

# Raises an exception, next_state can not be changed to next_state
# previous_state and default_state are allowed
>>> book.state = 'next_state'

# Raises an exception, too
>>> book.state = 'state_not_in_flow'

Hooks:

class Book(models.Model):
    state = StateField(max_length=20, state_flow=flow)

    # this method will be called when state changes from foo to bar
    def state_foo_to_bar(self):
        pass