added filter by shipping cost to product search

products/utils.py

@@ -125,6 +125,37 @@ def find_related_products_v3(keyword):
     return set(products_qs)
 
 
+def find_related_products_v6(keyword, shipping_cost=None):
+    """
+    Ranked product search
+
+    SearchVectors for the fields
+    SearchQuery for the value
+    SearchRank for relevancy scoring and ranking
+
+    allow filtering by:
+    - shipping cost
+    """
+    vector = SearchVector('name') + SearchVector('description') + SearchVector('tags__label') + SearchVector('attributes__label') + SearchVector('category__name')
+    query = SearchQuery(keyword)
+
+    products_qs = Product.objects.annotate(
+        rank=SearchRank(vector, query)
+    ).filter(rank__gt=0.05)     # removed order_by because its lost in casting
+
+    if shipping_cost is True:
+        # only instances with shipping costs
+        products_qs = products_qs.filter(
+            Q(shipping_cost__isnull=False)&
+            Q(shipping_cost__gte=1)
+        )
+    elif shipping_cost is False:
+        # only intances without shpping costs
+        products_qs = products_qs.filter(Q(shipping_cost=None)|Q(shipping_cost=0.00))
+
+    return set(products_qs)
+
+
 def find_related_products_v4(keyword):
     """
     Similarity-ranked search using trigrams