Quote as little as needed for a valid proxied web request

Co-authored-by: Wei Ouyang <oeway007@gmail.com>

Author: consideRatio

jupyter_server_proxy/handlers.py

@@ -141,7 +141,14 @@ def get_client_uri(self, protocol, host, port, proxied_path):
         else:
             client_path = proxied_path
 
-        client_path = quote(client_path)
+        # Quote spaces, åäö and such, but only enough to send a valid web
+        # request onwards. To do this, we mark the RFC 3986 specs' "reserved"
+        # and "un-reserved" characters as safe that won't need quoting. The
+        # un-reserved need to be marked safe to ensure the quote function behave
+        # the same in py36 as py37.
+        #
+        # ref: https://tools.ietf.org/html/rfc3986#section-2.2
+        client_path = quote(client_path, safe=":/?#[]@!$&'()*+,;=-._~")
 
         client_uri = '{protocol}://{host}:{port}{path}'.format(
             protocol=protocol,