Support Open Ranges for Range Lookup - convert None to 'infinity'

[Sven R. Kunze]

Hi Dev Team,

we recently came across the following issue. We wanted to search for an open ranges using the range lookup.

Model.objects.filter(date__range=(None, now()))
Model.objects.filter(date__range=(now(), None))

Right now, we monkey-patch Django like this:

from django.db.models.lookups import Range

class OpenRange(Range):
    lookup_name = 'range'

    def as_sql(self, compiler, connection):
        lhs, lhs_params = self.process_lhs(compiler, connection)
        rhs, rhs_params = self.process_rhs(compiler, connection)
        if not rhs_params[0]:
            rhs_params[0] = '-infinity'
        if not rhs_params[1]:
            rhs_params[1] = 'infinity'
        return "%s BETWEEN %s AND %s" % (lhs, rhs[0], rhs[1]), rhs_params

models.DateField.register_lookup(OpenRange)

Cheers,
Sven

[Simon Charette]

Any reason why you can't use date__gte and date__lte?

In order to accept this we'd have to make sure all the supported database engines are able to use open ranges (is infity supported for all datatypes?) and whether or not these engines will be smart enough to use an index if this value is used. For these reasons I'm -0 on adding this as it doesn't seem to bring benefits over the existing lt, gt and friends lookups.

[Tim Graham]

Feel free to reopen if Simon's concerns are incorrect.