Queryset.extra use case: iregex against regular expressions stored as fields

[Jeff Johnson]

As requested, here is an example of something I couldn't figure out how to do without using Queryset.extra().

Given an email address, find all regular expressions from the database that match the email address. It would be like doing iregex in reverse.

class EmailFilter(models.Model):
    regex = models.CharField(blank=False, max_length=128, db_index=True, help_text="Do not send to email addresses that match this regular expression.  Not case sensitive.  E.g.: ^admin@.*$")

    @classmethod
    def find_matching_rules(cls, email):
        return cls.objects.extra(where=['%s ~* regex'], params=[email])

[Tim Graham]

I believe that should be straightforward to implement ​using the expressions API. Please see TicketClosingReasons/UseSupportChannels if you need help converting it and reopen this ticket if there's some reason I'm missing why that won't work. Thanks.