Filter to allow multiple options in Char filters for DRF + django_filters

multiple_char_filter.py

import django_filters


class MultipleCharFilter(django_filters.CharFilter):
    """
    Allows multiple options in a comma separated list for Char fields.
    Example:
      - field=value       # filter by a single value
      - field=val1,val2   # Filter by val1 OR val2  (Django's 'in' lookup)
    """
    def filter(self, qs, value):
        if not value:
            return qs

        values = value.split(',')
        if len(values) > 1:
            self.lookup_expr = 'in'
        else:
            values = values[0]

        return super(MultipleCharFilter, self).filter(qs, values)