This package lets you use real Python (PEP435-style) enums with Django.
pip install django-choice-enumfields
from enumfields import EnumField
from enumfields import ChoiceEnum # Uses Ethan Furman's "enum34" backport
class Color(ChoiceEnum):
RED = 'r'
GREEN = 'g'
BLUE = 'b'
class MyModel(models.Model):
color = EnumField(Color, max_length=1)Elsewhere:
m = MyModel.objects.filter(color=Color.RED)NumEnumField works identically, but the underlying storage mechanism is an IntegerField instead of a CharField.
from enumfields import EnumField, EnumSubField
from enumfields import ChoiceEnum
class Color(ChoiceEnum):
RED = 'r'
GREEN = 'g'
BLUE = 'b'
class ColorType(ChoiceEnum):
LIGHT = Choice('l', 'light', parents=(Color.RED, Color.BLUE))
DARK = Choice('d', 'dark', parents=(Color.RED, Color.GREEN))
TRANSPARENT = Choice('t', 'transparent', parents=(Color.GREEN))
class MyModel(models.Model):
color = EnumField(Color, max_length=1)
color_type = EnumSubField('color', ColorType, max_length=1)
MyModel(color=Color.RED, color_type=ColorType.LIGHT).full_clean() # OK
MyModel(color=Color.RED, color_type=ColorType.TRANSPARENT).full_clean() # Raise ValidationErrorEnumSubField automatically validates if parents requirement is satisfied.
With EnumSubField, EnumField, NumEnumSubField and NumEnumField comes validation of initial and allowed transitions between choices out of the box.
from enumfields import EnumField
from enumfields import Choice, ChoiceEnum
class StateFlow(ChoiceEnum):
START = Choice('s', 'start', next={'PROCESSING'})
PROCESSING = Choice('p', 'processing', next={'END'}, initial=False)
END = Choice('e', 'end', next=set(), initial=False)
class MyModel(models.Model):
state = EnumField(StateFlow, max_length=1)
MyModel(state=StateFlow.START).full_clean() # OK
# Raise ValidationError because PROCESSING is not in initial states
MyModel(state=StateFlow.PROCESSING).full_clean()
model = MyModel.objects.create(StateFlow.START)
model.state = StateFlow.END
# Raise ValidationError because END is not next state after START
model.full_clean()
model.state = StateFlow.PROCESSING
model.full_clean() # OKCall the formfield method to use an EnumField directly in a Form.
class MyForm(forms.Form):
color = EnumField(Color, max_length=1).formfield()Normally, you just use normal PEP435-style enums, however, django-choice-enumfields also encludes its own version of ChoiceEnum with a few extra bells and whistles. Namely, the smart definition of labels which are used, for example, in admin dropdowns. By default, it will create labels by title-casing your constant names. You can provide custom labels with using Choice to define enum item.
from enumfields import EnumField, ChoiceEnum, Choice # Our own Enum class
class Color(ChoiceEnum):
RED = Choice('r', 'A custom label')
GREEN = 'g'
BLUE = 'b'
class MyModel(models.Model):
color = EnumField(Color, max_length=1)
assert Color.GREEN.label == 'Green'
assert Color.RED.label == 'A custom label'enumfields.admin.EnumFieldListFilter is provided to allow using enums in list_filter.
from enumfields.admin import EnumFieldListFilter
class MyModelAdmin(admin.ModelAdmin):
list_filter = [('color', EnumFieldListFilter)]