How to apply a filter backend to all fields of all resources in Django Rest Framework?

django, django-rest-framework

Solution

Right now you are telling Django REST Framework to use the `DjangoFilterBackend` for all views, but you are not telling it how the `FilterSet` should be generated.

`django-filter` will automatically generate a `FilterSet` for all of the fields on a model if the `fields` are set to `None`. Django REST Framework will automatically generate a `FilterSet` if `filter_fields` are not set to `None`, which means you won't be able to use the default `DjangoFilterBackend`.

You can create a custom `DjangoFilterBackend` though, which will automatically generate the `FilterSet` for all fields on the model.

from rest_framework.filters import DjangoFilterBackend

class AllDjangoFilterBackend(DjangoFilterBackend):
    """
    A filter backend that uses django-filter.
    """

    def get_filter_class(self, view, queryset=None):
        """
        Return the django-filters `FilterSet` used to filter the queryset.
        """
        filter_class = getattr(view, 'filter_class', None)
        filter_fields = getattr(view, 'filter_fields', None)

        if filter_class or filter_fields:
            return super(AllDjangoFilterBackend, self).get_filter_class(self, view, queryset)

        class AutoFilterSet(self.default_filter_set):
            class Meta:
                model = queryset.model
                fields = None

        return AutoFilterSet

This will still use the original filter backend for situations where the view defines a custom `filter_class` or `filter_fields`, but it will generate a custom `FilterSet` for all other situations. Keep in mind that you shouldn't allow fields which aren't returned through the API to be filtered, as you are opening yourself up to future security issues (like people filtering a user list by passwords).

Problem

I have a lot of resources and i want to apply the DjangoFilterBackend to all of them. Tried setting in `settings.py` ``` 'DEFAULT_FILTER_BACKENDS': [ 'rest_framework.filters.DjangoFilterBackend', ] ``` But it didn't work I tried adding only `filter_backends = (filters.DjangoFilterBackend,)` to one of my resources and it still didn't work. Only after I explicitly added `filter_fields = ('col1','col2',)` it started working with those fields only. Is there any way I can apply the filter backend to all resources and all fields (same way i do with permissions for example ... ) ? Thanks.

Original source