- args = dict(request.args)
- args.update(kwargs)
- return url_for(request.endpoint, **args)
+ args = MultiDict(request.args)
+
+ for key, value in kwargs.items():
+ if key == "_add":
+ for key2, value_to_add in value.items():
+ values = set(args.getlist(key2))
+ values.add(value_to_add)
+ args.setlist(key2, list(values))
+ elif key == "_remove":
+ for key2, value_to_remove in value.items():
+ values = set(args.getlist(key2))
+ values.discard(value_to_remove)
+ args.setlist(key2, list(values))
+ else:
+ args.setlist(key, [ value ])
+
+
+ dargs = dict(args.lists())
+
+ return url_for(request.endpoint, **dargs)