LDS I/O uses OAuth3, so it doesn't require an LDS I/O specific module.

See LDS I/O ruby sinatra example and ruby-oauth3.

Ruby / Sinatra OAuth2 authentication strategy for connecting to lds.org thru LDS Connect

gem install ldsconnect

require "ldsconnect"

client_id = '55c7-test-bd03'
client_secret = '6b2fc4f5-test-8126-64e0-b9aa0ce9a50d'
strategy = LdsConnect.new(client_id, client_secret, options={})

Apache2