From 525f4b60189add04fe3e9827ddebfb17478aa61f Mon Sep 17 00:00:00 2001
From: Ryan P Kilby <rpkilby@ncsu.edu>
Date: Fri, 26 Jan 2018 06:40:24 -0500
Subject: [PATCH 1/2] Refactor backend filterset instantiation

---
 django_filters/rest_framework/backends.py | 38 ++++++++++++++---------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/django_filters/rest_framework/backends.py b/django_filters/rest_framework/backends.py
index ff0e00c74..d401290d7 100644
--- a/django_filters/rest_framework/backends.py
+++ b/django_filters/rest_framework/backends.py
@@ -27,6 +27,14 @@ def template(self):
             return 'django_filters/rest_framework/crispy_form.html'
         return 'django_filters/rest_framework/form.html'
 
+    def get_filterset(self, request, queryset, view):
+        filterset_class = self.get_filterset_class(view, queryset)
+        if filterset_class is None:
+            return None
+
+        kwargs = self.get_filterset_kwargs(request, queryset, view)
+        return filterset_class(**kwargs)
+
     def get_filterset_class(self, view, queryset=None):
         """
         Return the `FilterSet` class used to filter the queryset.
@@ -71,27 +79,29 @@ class Meta(MetaBase):
 
         return None
 
+    def get_filterset_kwargs(self, request, queryset, view):
+        return {
+            'data': request.query_params,
+            'queryset': queryset,
+            'request': request,
+        }
+
     def filter_queryset(self, request, queryset, view):
-        filterset_class = self.get_filterset_class(view, queryset)
+        filterset = self.get_filterset(request, queryset, view)
+        if filterset is None:
+            return queryset
 
-        if filterset_class:
-            filterset = filterset_class(request.query_params, queryset=queryset, request=request)
-            if not filterset.is_valid() and self.raise_exception:
-                raise utils.translate_validation(filterset.errors)
-            return filterset.qs
-        return queryset
+        if not filterset.is_valid() and self.raise_exception:
+            raise utils.translate_validation(filterset.errors)
+        return filterset.qs
 
     def to_html(self, request, queryset, view):
-        filterset_class = self.get_filterset_class(view, queryset)
-        if not filterset_class:
+        filterset = self.get_filterset(request, queryset, view)
+        if filterset is None:
             return None
-        filterset = filterset_class(request.query_params, queryset=queryset, request=request)
 
         template = loader.get_template(self.template)
-        context = {
-            'filter': filterset
-        }
-
+        context = {'filter': filterset}
         return template.render(context, request)
 
     def get_coreschema_field(self, field):

From 009b30fe1c91aa2066ae5d0cd26e52cfdbcda989 Mon Sep 17 00:00:00 2001
From: Ryan P Kilby <rpkilby@ncsu.edu>
Date: Fri, 26 Jan 2018 08:50:36 -0500
Subject: [PATCH 2/2] Add DRF docs for filterset customization

---
 docs/guide/rest_framework.txt | 39 +++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/docs/guide/rest_framework.txt b/docs/guide/rest_framework.txt
index 4eaf54c90..480c819a7 100644
--- a/docs/guide/rest_framework.txt
+++ b/docs/guide/rest_framework.txt
@@ -105,6 +105,45 @@ You may bypass creating a ``FilterSet`` by instead adding ``filter_fields`` to y
             fields = ('category', 'in_stock')
 
 
+Overriding FilterSet creation
+-----------------------------
+
+``FilterSet`` creation can be customized by overriding the following methods on the backend class:
+
+* ``.get_filterset(self, request, queryset, view)``
+* ``.get_filterset_class(self, view, queryset=None)``
+* ``.get_filterset_kwargs(self, request, queryset, view)``
+
+You can override these methods on a case-by-case basis for each view, creating unique backends, or these methods can be used to write your own hooks to the view class.
+
+.. code-block:: python
+
+    class MyFilterBackend(filters.DjangoFilterBackend):
+        def get_filterset_kwargs(self, request, queryset, view):
+            kwargs = super().get_filterset_kwargs(request, queryset, view)
+
+            # merge filterset kwargs provided by view class
+            if hasattr(view, 'get_filterset_kwargs'):
+                kwargs.update(view.get_filterset_kwargs())
+
+            return kwargs
+
+
+    class BooksFilter(filters.FitlerSet):
+        def __init__(self, *args, author=None, **kwargs):
+            super().__init__(*args, **kwargs)
+            # do something w/ author
+
+
+    class BookViewSet(viewsets.ModelViewSet):
+        filter_backends = [MyFilterBackend]
+        filter_class = BookFilter
+
+        def get_filteset_kwargs(self):
+            return {
+                'author': self.get_author(),
+            }
+
 Schema Generation with Core API
 -------------------------------