Apache HTTP async client SOCKSv4 Connection Demo

Plugs into Apache's HTTP async client to open a connection via a SOCKSv4 proxy. This proxy can be set per request with the RequestConfig.

It currently only supports SOCKSv4. Adding SOCKSv4a and SOCKSv5 should be straightforward with the given extension points. Either a new session scheme socks5 could be added or the SOCKS connection handling be adapted like in java.net.SocksSocketImpl that can degrade von v5 to v4.

How it works

• A SchemeIOSessionStrategy is injected that supports the socks scheme.
  • It wraps the IOSession in a Socks4IOSession
  • The Socks4IOSession puts itself on the IOSession with a session attribute
  • A SOCKS connect package is sent (see RFC)
• In order to be able to await the SOCKS reply the DefaultConnectingIOReactor was extended with SocksConnectingIOReactor to wrap the IOEventDispatch on execute(..) with the SocksIOEventDispatchProxy
• The SocksIOEventDispatchProxy
  • extracts the Socks4IOSession from the session attributes on inputReady(..)
  • Socks4IOSession receives and verifies the SOCKS response
  • does some ugly error handling