checkcerts.rb

require "net/https"
require "openssl"

store = OpenSSL::X509::Store.new

ssl_cert_glob =
  File.expand_path "../lib/rubygems/ssl_certs/*.pem", __FILE__

Dir.glob(ssl_cert_glob).each do |ssl_cert|
  store.add_file ssl_cert
end

hosts = %w(
  d2chzxaqi4y7f8.cloudfront.net
  rubygems.org
  s3.amazonaws.com
  staging.rubygems.org
)

hosts.each do |host|
  puts "Testing #{host}..."

  begin
    http = Net::HTTP.new(host, 443)
    http.use_ssl = true
    http.verify_mode = OpenSSL::SSL::VERIFY_PEER
    http.cert_store = store
    http.head('/')
  rescue Errno::ENOENT
    warn "#{host} seems offline, I can't tell whether ssl would work."
  rescue OpenSSL::SSL::SSLError => e
    # Only fail for certificate verification errors
    if e.message =~ /certificate verify failed/
      warn "#{host} is not verifiable using the included certificates. Error was: #{e.message}"
    end
  end
end

Error:

C:\Users\Luis\Code\rubygems\rubygems>ruby checkcerts.rb
Testing d2chzxaqi4y7f8.cloudfront.net...
Testing rubygems.org...
Testing s3.amazonaws.com...
Testing staging.rubygems.org...
checkcerts.rb:34: staging.rubygems.org is not verifiable using the included certificates. Error was: SSL_connect returne
d=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed (RuntimeError)
        from checkcerts.rb:20:in `each'
        from checkcerts.rb:20