A mixin for ``django-rest-framework``providing the possibility to filter the queryset based on query parameters.

filter_model_mixin.py

from django.db.models import fields as django_fields


class FilteredModelViewSetMixin(object):
    """
    A mixin providing the possibility to filter the queryset based on
    query parameters.

    The mixin overrides the ``get_queryset`` method to return the original
    queryset additionally filtered based on the query string parameters.

    The filtering is performed by doing a test for direct equality with the
    query parameter for all field types except the BooleanField where the
    received value is parsed into a ``bool`` instance based on its string
    representation ("true" or "false", case insensitive).

    Classes mixing-in the Mixin should provide the ``filter_fields``
    property to provide a list of fields for which filtering should
    be supported.
    """
    filter_fields = None

    def get_queryset(self):
        qs = super(FilteredModelViewSetMixin, self).get_queryset()
        if self.filter_fields is None:
            return qs

        for filter_field_name in self.filter_fields:
            if filter_field_name in self.request.QUERY_PARAMS:
                filter_value = self.request.QUERY_PARAMS[filter_field_name]

                # Special casing the value which is passed to the QS
                # filter method for certain types of fields
                field = self.model._meta.get_field(filter_field_name)
                if isinstance(field, django_fields.BooleanField):
                    filter_value = filter_value.lower()
                    if filter_value not in ('true', 'false'):
                        # Ignore the filter if the value is invalid
                        continue

                    filter_value = filter_value.lower() == 'true'

                qs = qs.filter(**{
                    filter_field_name: filter_value,
                })

        return qs