How do you configure WEBrick to use SSL in Rails?

While the scripts directory in Rails 4 is gone, the bin directory remains. You can get WEBrick working with an SSL certificate by editing the bin/rails script. Tested on Rails 4 and Ruby 2.1.1, installed with rbenv.

Much of this is from this blog post and this Stack Overflow question.

#!/usr/bin/env ruby

require 'rails/commands/server'
require 'rack'
require 'webrick'
require 'webrick/https'

if ENV['SSL'] == "true"
  module Rails
      class Server < ::Rack::Server
          def default_options
              super.merge({
                  :Port => 3001,
                  :environment => (ENV['RAILS_ENV'] || "development").dup,
                  :daemonize => false,
                  :debugger => false,
                  :pid => File.expand_path("tmp/pids/server.pid"),
                  :config => File.expand_path("config.ru"),
                  :SSLEnable => true,
                  :SSLVerifyClient => OpenSSL::SSL::VERIFY_NONE,
                  :SSLPrivateKey => OpenSSL::PKey::RSA.new(
                                   File.open("certs/server.key").read),
                  :SSLCertificate => OpenSSL::X509::Certificate.new(
                                   File.open("certs/server.crt").read),
                  :SSLCertName => [["CN", WEBrick::Utils::getservername]],
              })
          end
      end
  end
end

APP_PATH = File.expand_path('../../config/application',  __FILE__)
require_relative '../config/boot'
require 'rails/commands'

Starting the rails server from the app directory works to start an SSL enabled server now when the SSL environment variable is set to true, and the default rails settings are retained when the environment variable is omitted.

$ SSL=true rails s
=> Booting WEBrick
=> Rails 4.1.0 application starting in development on https://0.0.0.0:3001
=> Run `rails server -h` for more startup options
=> Notice: server is listening on all interfaces (0.0.0.0). Consider using 127.0.0.1 (--binding option)
=> Ctrl-C to shutdown server
[2014-04-24 22:59:10] INFO  WEBrick 1.3.1
[2014-04-24 22:59:10] INFO  ruby 2.1.1 (2014-02-24) [x86_64-darwin13.0]
[2014-04-24 22:59:10] INFO  
Certificate:
    Data:
...

If you don’t want to use a pre generated certificate, you can use WEBrick’s Utils::create_self_signed_cert, as outlined in this answer:

Configure WEBrick to use automatically generated self-signed SSL/HTTPS certificate