Ignoring empty query string parameters sent to search endpoint (#337)

These empty parameters cause errors, resulting in failed responses.

ECOM-5685

course_discovery/apps/api/filters.py

@@ -4,6 +4,7 @@ import django_filters
 from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.db.models import QuerySet
+from django.http import QueryDict
 from django.utils.translation import ugettext as _
 from drf_haystack.filters import HaystackFacetFilter, HaystackFilter as DefaultHaystackFilter
 from drf_haystack.query import FacetQueryBuilder
@@ -59,14 +60,29 @@ class FacetQueryBuilderWithQueries(FacetQueryBuilder):
         return query
 
 
-class HaystackFacetFilterWithQueries(HaystackFacetFilter):
+class HaystackRequestFilterMixin:
+    @staticmethod
+    def get_request_filters(request):
+        filters = HaystackFacetFilter.get_request_filters(request)
+
+        # Remove items with empty values
+        filters = dict((k, v) for k, v in filters.items() if v)
+
+        # Convert the dict to a QueryDict to maintain the contract of the original method.
+        query_dict = QueryDict('', mutable=True)
+        query_dict.update(filters)
+
+        return query_dict
+
+
+class HaystackFacetFilterWithQueries(HaystackRequestFilterMixin, HaystackFacetFilter):
     query_builder_class = FacetQueryBuilderWithQueries
 
 
-class HaystackFilter(DefaultHaystackFilter):
+class HaystackFilter(HaystackRequestFilterMixin, DefaultHaystackFilter):
     @staticmethod
     def get_request_filters(request):
-        filters = HaystackFacetFilter.get_request_filters(request)
+        filters = HaystackRequestFilterMixin.get_request_filters(request)
 
         # Return data for the default partner, if no partner is requested
         if not any(field in filters for field in ('partner', 'partner_exact')):

course_discovery/apps/api/tests/test_filters.py

+import ddt
+from django.test import TestCase
+from rest_framework.test import APIRequestFactory
+from rest_framework.views import APIView
+
+from course_discovery.apps.api.filters import HaystackRequestFilterMixin
+
+
+@ddt.ddt
+class HaystackRequestFilterMixinTests(TestCase):
+    def test_get_request_filters(self):
+        """ Verify the method removes query parameters with empty values """
+        request = APIRequestFactory().get('/?q=')
+        request = APIView().initialize_request(request)
+        filters = HaystackRequestFilterMixin.get_request_filters(request)
+        self.assertDictEqual(filters, {})

course_discovery/apps/api/v1/tests/test_views/test_search.py

@@ -222,3 +222,12 @@ class AggregateSearchViewSet(DefaultPartnerMixin, SerializationMixin, LoginMixin
         response_data = json.loads(response.content.decode('utf-8'))
         self.assertListEqual(response_data['objects']['results'],
                              [self.serialize_course_run(other_course_run), self.serialize_program(other_program)])
+
+    def test_empty_query(self):
+        """ Verify, when the query (q) parameter is empty, the endpoint behaves as if the parameter
+        was not provided. """
+        course_run = CourseRunFactory(course__partner=self.partner, status=CourseRunStatus.Published)
+        response = self.get_search_response({'q': ''})
+        self.assertEqual(response.status_code, 200)
+        response_data = json.loads(response.content.decode('utf-8'))
+        self.assertListEqual(response_data['objects']['results'], [self.serialize_course_run(course_run)])