How to choose particular gem in Gemfile based on current RVM?

Question

How can I conditionally choose which gem to use based on the Ruby VM currently in use?

Ideally I would like something like:

if [using jruby]
    gem 'jruby-openssl'

This would only require the jruby-openssl if the RVM being used is JRuby.

Answer 1

Use the following in your Gemfile, as documented here: https://github.com/jruby/activerecord-jdbc-adapter

platforms :ruby do
  gem 'sqlite3'
end

platforms :jruby do
  gem 'jruby-openssl'
  gem 'activerecord-jdbcsqlite3-adapter'
end