django-extended-choices

A little application to improve django choices (or whatever: no dependencies)

django-extended-choices aims to provide a better (ie for me), and more readble way of using choices in django

Installation

You can install directly from the github repo:

$ git clone git://github.com/twidi/django-extended-choices.git
$ cd django-extended-choices
$ sudo python setup.py install

Usage

The aim is to replace this:

STATE_ONLINE  = 1
STATE_DRAFT   = 2
STATE_OFFLINE = 3

STATE_CHOICES = (
    (STATE_ONLINE,  'Online'),
    (STATE_DRAFT,   'Draft'),
    (STATE_OFFLINE, 'Offline'),
)

STATE_DICT = dict(STATE_CHOICES)

class ContentModel(models.Model):
    title      = models.CharField(max_length=255)
    content    = models.TextField()
    state      = models.PositiveSmallIntegerField(choices=STATE_CHOICES, default=STATE_DRAFT)
    related_to = models.ManyToManyField('self', through="ContentToContent", symmetrical=False, blank=True, null=True)

    def __unicode__(self):
        return u'Content "%s" (state=%s)' % (self.title, STATE_DICT[self.state])

    def get_related_content(self):
        return self.related_to.select_related().filter(state=STATE_ONLINE)

by this

from extended_choices import Choices

STATES = Choices(
    ('ONLINE',  1, 'Online'),
    ('DRAFT',   2, 'Draft'),
    ('OFFLINE', 3, 'Offline'),
)

class ContentModel(models.Model):
    title      = models.CharField(max_length=255)
    content    = models.TextField()
    state      = models.PositiveSmallIntegerField(choices=STATES.CHOICES, default=STATES.DRAFT)
    related_to = models.ManyToManyField('self', through="ContentToContent", symmetrical=False, blank=True, null=True)

    def __unicode__(self):
        return u'Content "%s" (state=%s)' % (self.title, STATES.CHOICES_DICT[self.state])

    def get_related_content(self):
        return self.related_to.select_related().filter(state=STATES.ONLINE)

As you can see, there is only one declaration for all states, with, for each state in order:

• the pseudo-constant name which can be used (STATES.ONLINE replace the previous STATE_ONLINE)
• the value to use as key in database
• the name to be displayed

And then, you can use:

• STATES.CHOICES to use with choices= in fields declarations
• STATES.CHOICES_DICT a dict to get the value to display with the key used in database
• STATES.REVERTED_CHOICES_DICT, a dict to get the key from the displayable value (can be usefull in some case)

To use another name than CHOICES by passing a name parameter as a named argument to the constructor:

STATES = Choices(
    ('ONLINE',  1, 'Online'),
    ('DRAFT',   2, 'Draft'),
    ('OFFLINE', 3, 'Offline'),
    name = 'OUR_STATES'
)

# ...
    state = models.PositiveSmallIntegerField(choices=STATES.OUR_STATES, default=STATES.DRAFT)
# ...

And you can add others choices within the same variable:

STATES.add_choices('OLD_STATES', (
    ('VISIBLE', 10, 'Visible'),
    ('HIDDEN',  20, 'Hidden'),
))

class ContentModel(models.Model):
# ...
    state     = models.PositiveSmallIntegerField(choices=STATES.OUR_STATES, default=STATES.DRAFT)
    old_state = models.PositiveSmallIntegerField(choices=STATES.OLD_STATES, default=STATES.VISIBLE)
# ...
    def __unicode__(self):
        return u'Content "%s" (state=%s, old state=%s)' % (self.title, STATES.OUR_STATES_DICT[self.state], STATES.OLD_STATES[self.old_state])

When add_choices is used, the CHOICES (here STATES.OLD_STATES), and the two dictionnaries are initialized. If a constant name (firt entry in a tuple) is declared more than one time, the first declared value (second entry of a tuple) is used.

You can declarer your choices where you want. My usage is in the models.py file, just before the class declaration.

License

Licensed under the General Public License (GPL). See the License file included

Source code

The source code is available on github

Author

Written by Stephane Angel <[email protected]> (http://twidi.com), originally for http://www.liberation.fr