In article <e0b1e5700808260950s79665563h3615a7af3ad4cc0b / mail.gmail.com>,
  "Yusuke ENDOH" <mame / tsg.ne.jp> writes:

> This is because Apache, which rubyforge uses, seems to handle
> If-Modified-Since field only when it is represented in GMT.
> This is not a fault of rubygems, but I think it's better for
> rubygems to convert last_modified in GMT.

See HTTP-date definition of RFC 2616.

> -      request.add_field 'If-Modified-Since', last_modified.rfc2822
> +      request.add_field 'If-Modified-Since', last_modified.dup.gmtime.rfc2822

I recommend Time#httpdate.
-- 
Tanaka Akira