Django (postgres) ArrayField Multiple Choices as checkboxes.

fields.py

# https://gist.github.com/danni/f55c4ce19598b2b345ef
from django import forms
from django.contrib.postgres.fields import ArrayField


class MultipleChoiceArrayField(ArrayField):
    def formfield(self, **kwargs):
        defaults = {
            "form_class": forms.MultipleChoiceField,
            "choices": self.base_field.choices,
            "widget": forms.CheckboxSelectMultiple,
            **kwargs,
        }
        return super(ArrayField, self).formfield(**defaults)

    def to_python(self, value):
        res = super().to_python(value)
        if isinstance(res, list):
            value = [self.base_field.to_python(val) for val in res]
        return value

models.py

from django.db import models
from .fields import MultipleChoiceArrayField


class Config(models.Model):
    # https://docs.python.org/3/library/datetime.html#datetime.date.weekday
    class Weekdays(models.IntegerChoices):
        MONDAY = 0, "Monday"
        TUESDAY = 1, "Tuesday"
        WEDNESDAY = 2, "Wednesday"
        THURSDAY = 3, "Thursday"
        FRIDAY = 4, "Friday"
        SATURDAY = 5, "Saturday"
        SUNDAY = 6, "Sunday"

        @classmethod
        def get_default_weekdays(cls):
            return [
                cls.MONDAY,
                cls.TUESDAY,
                cls.WEDNESDAY,
                cls.THURSDAY,
                cls.FRIDAY,
            ]

    valid_weekdays = MultipleChoiceArrayField(
        models.PositiveSmallIntegerField("Valid week days", choices=Weekdays),
        size=7,
        default=Weekdays.get_default_weekdays,
    )