Add unaccent to SearchFilter

docs/api-guide/filtering.md

@@ -230,6 +230,7 @@ The search behavior may be specified by prefixing field names in `search_fields`
 | `$`    | `iregex`      | Regex search.      |
 | `@`    | `search`      | Full-text search (Currently only supported Django's [PostgreSQL backend][postgres-search]). |
 | None   | `icontains`   | Contains search (Default).  |
+| `&`    | `unaccent`    | Accent-insensitive search. (Currently only supported Django's [PostgreSQL backend][postgres-lookups]). |
 
 For example:
 
@@ -370,3 +371,4 @@ The [djangorestframework-word-filter][django-rest-framework-word-search-filter]
 [HStoreField]: https://docs.djangoproject.com/en/stable/ref/contrib/postgres/fields/#hstorefield
 [JSONField]: https://docs.djangoproject.com/en/stable/ref/models/fields/#django.db.models.JSONField
 [postgres-search]: https://docs.djangoproject.com/en/stable/ref/contrib/postgres/search/
+[postgres-lookups]: https://docs.djangoproject.com/en/stable/ref/contrib/postgres/lookups/#unaccent

rest_framework/filters.py

@@ -58,6 +58,7 @@ class SearchFilter(BaseFilterBackend):
         '=': 'iexact',
         '@': 'search',
         '$': 'iregex',
+        '&': 'unaccent',
     }
     search_title = _('Search')
     search_description = _('A search term.')

tests/test_filters.py

@@ -247,6 +247,26 @@ def as_sql(self, compiler, connection):
                 {'id': 2, 'title': 'zz', 'text': 'bcd'},
             ]
 
+    @pytest.mark.requires_postgres
+    def test_search_field_with_unaccent(self):
+        SearchFilterModel.objects.create(title='Jeremy', text='jeremy')
+        SearchFilterModel.objects.create(title='Jérémy', text='jérémy')
+        SearchFilterModel.objects.create(title='Jérémie', text='jérémie')
+        SearchFilterModel.objects.create(title='Jeremie', text='jeremie')
+
+        class SearchListView(generics.ListAPIView):
+            queryset = SearchFilterModel.objects.all()
+            serializer_class = SearchFilterSerializer
+            filter_backends = (filters.SearchFilter,)
+            search_fields = ('&title',)
+
+        view = SearchListView.as_view()
+
+        request = factory.get('/', {'search': 'Jerem'})
+        response = view(request)
+        assert len(response.data) == 4
+        assert {item['title'] for item in response.data} == {'Jeremy', 'Jérémy', 'Jérémie', 'Jeremie'}
+
     def test_search_field_with_multiple_words(self):
         class SearchListView(generics.ListAPIView):
             queryset = SearchFilterModel.objects.all()