Problem of trying to get gmail atom feed in ruby

I write some simple ruby code to try to get gmail atom feed:

http = Net::HTTP::new(‘mail.google.com’, 443);
http.use_ssl = true ;
http.start {
request = Net::HTTP::Get.new(’/mail/feed/atom"’);
request.basic_auth(USERNAME,PASSWORD);
response = http.request(request)
response.value
puts response.body
}

But it is fail…

warning: peer certificate won’t be verified in this SSL session
/usr/lib/ruby/1.8/net/http.rb:2097:in error!': 400 "Bad Request" (Net::HTTPServerException) from /usr/lib/ruby/1.8/net/http.rb:2106:invalue’
from /home/carfield/respository/atomtest.rb:13
from /usr/lib/ruby/1.8/net/http.rb:543:in `start’
from /home/carfield/respository/atomtest.rb:9

Anyone know how can I solve it? Done a brief google search doesn’t
help…