The http proxy server convert text/html content encoding from gb+ to utf-8. It is base on webrick/httpproxy and ruby.

The gbconv is running on windows platform. But you can play it on +nix by a little change. It primarily includes fork, kill and other codes that base on win32/process extension. This program is very tiny and basic. Line count less than 300.

At last I should say thanks to Thomas Metge who built shrew project that I make referenced.