Add special _index, _404 and _default keys

src/handler.py

@@ -37,17 +37,27 @@ def get_url_content(url):
     }
     return targets
 
+def get_dict_entry_fallback(d, key, fallback):
+    if key and key in d:
+        return d[key]
+    if fallback in d:
+        return d[fallback]
+    return d.get('_default', None)
 
 def get_entry(args, targets):
     while args:
         arg = args.pop(0)
         if not arg:
             continue
-        targets = targets.get(arg, None)
+
+        # Fallback to _404 if the key is not found
+        targets = get_dict_entry_fallback(targets, arg, '_404')
         if isinstance(targets, dict):
             continue
         return targets, args
-    return None, args
+
+    # Try to match an index entry
+    return get_dict_entry_fallback(targets, '', '_index'), args
 
 def get_entry_for_url(url, args):
     targets = get_url_content(url)