example nested facet backend

Author: barseghyanartur

examples/simple/search_indexes/backends/__init__.py

@@ -0,0 +1 @@
+from .nested_continents import *

examples/simple/search_indexes/backends/nested_continents.py

@@ -0,0 +1,63 @@
+from django_elasticsearch_dsl_drf.filter_backends.mixins import (
+    FilterBackendMixin,
+)
+from rest_framework.filters import BaseFilterBackend
+
+__all__ = ('NestedContinentsBackend',)
+
+
+class NestedContinentsBackend(BaseFilterBackend, FilterBackendMixin):
+    """Adds nesting to continents."""
+
+    faceted_search_param = 'nested_facet'
+
+    def get_faceted_search_query_params(self, request):
+        """Get faceted search query params.
+
+        :param request: Django REST framework request.
+        :type request: rest_framework.request.Request
+        :return: List of search query params.
+        :rtype: list
+        """
+        query_params = request.query_params.copy()
+        return query_params.getlist(self.faceted_search_param, [])
+
+    def filter_queryset(self, request, queryset, view):
+        """Filter the queryset.
+        :param request: Django REST framework request.
+        :param queryset: Base queryset.
+        :param view: View.
+        :type request: rest_framework.request.Request
+        :type queryset: elasticsearch_dsl.search.Search
+        :type view: rest_framework.viewsets.ReadOnlyModelViewSet
+        :return: Updated queryset.
+        :rtype: elasticsearch_dsl.search.Search
+        """
+        facets = self.get_faceted_search_query_params(request)
+
+        if 'continent' in facets:
+            queryset \
+                .aggs\
+                .bucket('continents',
+                        'nested',
+                        path='continent') \
+                .bucket('continent_name',
+                        'terms',
+                        field='continent.name.raw',
+                        size=10) \
+                .bucket('counties',
+                        'nested',
+                        path='continent.country') \
+                .bucket('country_name',
+                        'terms',
+                        field='continent.country.name.raw',
+                        size=10) \
+                .bucket('city',
+                        'nested',
+                        path='continent.country.city') \
+                .bucket('city_name',
+                        'terms',
+                        field='continent.country.city.name.raw',
+                        size=10)
+
+        return queryset

examples/simple/search_indexes/viewsets/address.py

@@ -19,6 +19,7 @@
 from django_elasticsearch_dsl_drf.pagination import LimitOffsetPagination
 from django_elasticsearch_dsl_drf.viewsets import DocumentViewSet
 
+from ..backends import NestedContinentsBackend
 from ..documents import AddressDocument
 from ..serializers import AddressDocumentSerializer
 
@@ -40,6 +41,7 @@ class AddressDocumentViewSet(DocumentViewSet):
         SearchFilterBackend,
         GeoSpatialFilteringFilterBackend,
         GeoSpatialOrderingFilterBackend,
+        NestedContinentsBackend,
         DefaultOrderingFilterBackend,
         SuggesterFilterBackend,
     ]
@@ -120,12 +122,4 @@ class AddressDocumentViewSet(DocumentViewSet):
             'field': 'city.country.name.raw',
             'enabled': True,
         },
-        'city2': {
-            'field': 'country.city.name.raw',
-            'enabled': True,
-        },
-        'country2': {
-            'field': 'country.name.raw',
-            'enabled': True,
-        },
     }