I've been using the workaround shown at http://blog.zenspider.com/2008/05/httpsssl-warning-cleanup.html for a while now to eliminate the "using default DH parameters" warning you get when using https in Ruby. However, I recently tried to reference two of my libraries which contained the same workaround in a script and ran into a "stack level too deep" error as the two sets of code both tried to alias the use_ssl= method. I spent some time working on this today and I think I've come up with a better method.

Net::HTTP.ssl_context_accessor(:tmp_dh_callback)
http = Net::HTTP.new('www.example.com', 443)
http.tmp_dh_callback = proc {
  OpenSSL::PKey::DH.new(IO.read('dhparams')) }
http.use_ssl = true

There are a few options for how you create the Diffie-Hellman params. The code above assumes you've got a file with pre-generated params (this is perfectly acceptable from a security standpoint). You can create the file with the "openssl dhparam" command, or a little Ruby script. You could also generate the DH params on the fly, although this can be quite slow:

Net::HTTP.ssl_context_accessor(:tmp_dh_callback)
http = Net::HTTP.new('www.example.com', 443)
http.tmp_dh_callback = proc { OpenSSL::PKey::DH.new(2048) }
http.use_ssl = true

Or if you just want the warning to go away and aren't concerned about the security implications you can just use as empty proc as zenspider did. I've tried to look at the Ruby OpenSSL library source and figure out what happens when the proc doesn't return anything but the code is a bit too obtuse for me to figure out.

Net::HTTP.ssl_context_accessor(:tmp_dh_callback)
http = Net::HTTP.new('www.example.com', 443)
http.tmp_dh_callback = proc {}
http.use_ssl = true