Fall back to netloc for bang search if query is empty

Previously, empty bang searches would redirect to the Whoogle instance
home page. This now redirects to the specific site for the bang search
instead (i.e. "!yt" without a query redirects to "youtube.com", "!gh" to
"github.com", etc)

Fixes #719

app/routes.py

@@ -306,7 +306,7 @@ def search():
     search_util = Search(request, g.user_config, g.session_key)
     query = search_util.new_search_query()
 
-    bang = resolve_bang(query, bang_json, url_for('.index'))
+    bang = resolve_bang(query, bang_json)
     if bang:
         return redirect(bang)
 

app/utils/bangs.py

@@ -1,5 +1,6 @@
 import json
 import requests
+import urllib.parse as urlparse
 
 DDG_BANGS = 'https://duckduckgo.com/bang.v255.js'
 
@@ -38,7 +39,7 @@ def gen_bangs_json(bangs_file: str) -> None:
     print('* Finished creating ddg bangs json')
 
 
-def resolve_bang(query: str, bangs_dict: dict, fallback: str) -> str:
+def resolve_bang(query: str, bangs_dict: dict) -> str:
     """Transform's a user's query to a bang search, if an operator is found
 
     Args:
@@ -65,8 +66,11 @@ def resolve_bang(query: str, bangs_dict: dict, fallback: str) -> str:
             operator[0], ''
         ).strip()
 
+        bang_url = bangs_dict[operator]['url']
+
         if bang_query:
-            return bangs_dict[operator]['url'].replace('{}', bang_query, 1)
+            return bang_url.replace('{}', bang_query, 1)
         else:
-            return fallback
+            parsed_url = urlparse.urlparse(bang_url)
+            return f'{parsed_url.scheme}://{parsed_url.netloc}'
     return ''