Adding a new meta option is very unlikely to happen.
Really, this is a question about dynamic choices, rather than just
inheritance. I'd rather see some sort of solution which allows some
(optional) hooks to customise choices on a per-class (or maybe even per
instance) basis. This is tricky though as choices are generally seen to be
a static attribute of the field.
On 25 August 2016 at 16:09, Anton Ponomarenko <unique.zettafl...@gmail.com>
wrote:
> From the doc: "Abstract base classes are useful when you want to put some
> common information into a number of other models". In my current project I
> put all common fields in abstact class, but those fields that use 'choice'
> option may have different choices in different child classes.
>
> Code Example:
>
> class AbstractProfile(models.Model):
> # Basic choices, which may vary in different classes
> PRIVACY_CHOICES = (
> (1, _('all')),
> (2, _('no one')),
> )
>
> title = models.CharField(_('title'), max_length=30)
> info = models.TextField(_('information'), max_length=500, blank=True)
> info_privacy = models.IntegerField(_('show information to'), default=1
> , choices=PRIVACY_CHOICES)
>
> city = models.CharField(_('location'), max_length=30, blank=True)
> address = models.CharField(_('address'), max_length=30, blank=True)
> address_privacy = models.IntegerField(_('show address to'), default=1,
> choices=PRIVACY_CHOICES)
>
> class Meta:
> abstract = True
>
> class UserProfile(AbstractProfile):
> PRIVACY_CHOICES = (
> (1, _('all')),
> (2, _('friends')),
> (3, _('friends of friends')),
> (4, _('only me')),
> )
>
> GENDER_CHOICES = (
> (1, _('man')),
> (2, _('woman')),
> )
>
> title = None
>
> first_name = models.CharField(_('first name'), max_length=30, blank=
> True)
> last_name = models.CharField(_('last name'), max_length=30, blank=True
> )
> names_privacy = models.IntegerField(_('show names to'), default=1,
> choices=PRIVACY_CHOICES)
>
> birth_date = models.DateField(_('birth date'), null=True, blank=True)
> birth_date_privacy = models.IntegerField(_('show birth date to'),
> default=1, choices=PRIVACY_CHOICES)
>
> gender = models.IntegerField(_('gender'), null=True, blank=True,
> choices=GENDER_CHOICES)
>
> avatar = models.ImageField(upload_to='users/avatar', null=True, blank=
> True)
>
> class CompanyProfile(AbstractProfile):
> PRIVACY_CHOICES = (*** new choices, which are different to those
> which are in abstract class ***)
>
> class TeamProfile(AbstractProfile):
> pass
>
> There is a proposition to add to the 'class Meta' a new attribute, which
> lets to define, whether to use CHOICES from abstract class or use those
> which exists in the current class, something like:
> class UserProfile(AbstractProfile):
> PRIVACY_CHOICES = (
> (1, _('all')),
> (2, _('friends')),
> (3, _('friends of friends')),
> (4, _('only me')),
> )
>
> GENDER_CHOICES = (
> (1, _('man')),
> (2, _('woman')),
> )
>
> title = None
>
> first_name = models.CharField(_('first name'), max_length=30, blank=
> True)
> last_name = models.CharField(_('last name'), max_length=30, blank=True
> )
> names_privacy = models.IntegerField(_('show names to'), default=1,
> choices=PRIVACY_CHOICES)
>
> birth_date = models.DateField(_('birth date'), null=True, blank=True)
> birth_date_privacy = models.IntegerField(_('show birth date to'),
> default=1, choices=PRIVACY_CHOICES)
>
> gender = models.IntegerField(_('gender'), null=True, blank=True,
> choices=GENDER_CHOICES)
>
> avatar = models.ImageField(upload_to='users/avatar', null=True, blank=
> True)
>
> class Meta:
> use_choices = [PRIVACY_CHOICES]
>
> Possible variants:
> Variant A: Use CHOICES from abstract class - do not add anything to 'class
> Meta'
> Variant B: Use CHOICES from current class instead of abstract class - add:
> class Meta:
> use_choices = [*** list of choices of current class **]
>
> Variant C: Same as B, but change format a bit:
> class Meta:
> use_choices = ((ABSTRACT_CHOICES_NAME1, CURRENT_CLASS_CHOICES_NAME1),
> (ABSTRACT_CHOICES_NAME2, CURRENT_CLASS_CHOICES_NAME2),)
> just in case, if a developer for some reasons have different names of
> choices
>
> This feature lets to have development process as DRY as possible, which is
> the reason why abstract class exists.
>
> In order to solve it, currenty I use the next code:
> # models.py
> class UserProfile(AbstractProfile):
> PRIVACY_CHOICES = (
> (1, _('all')),
> (2, _('friends')),
> (3, _('friends of friends')),
> (4, _('only me')),
> )
>
> # NEW PIECE OF CODE
> def __init__(self, *args, **kwargs):
> def get_class_attrs(cls):
> return re.findall(r'\w+(?=[,\)])', cls.__dict__['__doc__'])
>
> super(UserProfile, self).__init__(*args, **kwargs)
>
> all_fields = get_class_attrs(UserProfile)
> for each_field in all_fields:
> # all fields with '_privacy' in the name have 'choice' option
> if '_privacy' in each_field:
> self._meta.get_field(each_field).choices = self.
> PRIVACY_CHOICES
>
> default_privacy_choice = self.PRIVACY_CHOICES[0][0]
> if self._meta.get_field(each_field).default !=
> default_privacy_choice:
> self._meta.get_field(each_field).default =
> default_privacy_choice
> # END OF NEW PIECE OF CODE
>
> title = None
> *** rest fields ***
>
> # forms.py
> class UserProfileForm(forms.ModelForm):
> class Meta:
> model = UserProfile() # old_version was: model = UserProfile
> fields = (*** fields ***)
> but I dont like this way.
>
> Thanks
>
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