Case insensitive unique model fields in Django?

Question

I have basically a username is unique (case insensitive), but the case matters when displaying as provided by the user.

I have the following requirements:

Answer 1

You can also override "get_prep_value" by Django Models Field

class LowerCaseField:
    def get_prep_value(self, value):
        if isinstance(value, Promise):
            value = value._proxy____cast()
        if value:
            value = value.strip().lower()
        return value


class LCSlugField(LowerCaseField, models.SlugField):
    pass


class LCEmailField(LowerCaseField, models.EmailField):
    pass

email = LCEmailField(max_length=255, unique=True)