Asynchronous HTTP client

[Ping]

Hi,

I'm trying to find a way to create an asynchronous HTTP client so I
can get responses from web servers in a way like

  async_http_open('http://example.com/', callback_func)
  # immediately continues, and callback_func is called with response
as arg when it is ready

It seems twisted can do it, but I hesitate to bring in such a big
package as a dependency because my client should be light. Asyncore
and asynchat are lighter but they don't speak HTTP. The asynchttp
project on sourceforge is a fusion between asynchat and httplib, but
it hasn't been updated since 2001 and is seriously out of sync with
httplib.

I'd appreciate it if anyone can shed some lights on this.

Thanks,
Ping