Hey, you've got LiveReload in my Rack! No need for browser extensions anymore! Just plug it in your middleware stack and go!

Use this with guard-livereload for maximum fun!

Install

gem install rack-livereload

Using in...

Rails

In config/environments/development.rb:

MyApp::Application.configure do
  config.middleware.insert_before(Rack::Lock, Rack::LiveReload)

  # ...or, change some options...

  config.middleware.insert_before(
    Rack::Lock, Rack::LiveReload,
    :min_delay => 500,
    :max_delay => 10000,
    :port => 56789,
    :host => 'myhost.cool.wow'
  )
end

config.ru/Sinatra

require 'rack-livereload'

use Rack::LiveReload
# ...or...
use Rack::LiveReload, :min_delay => 500, ...

How it works

The necessary script tag to bring in a copy of livereload.js is injected right before the closing head tag in any text/html pages that come through. The script tag is built in such a way that the HTTP_HOST is used as the LiveReload host, so you can connect from external machines (say, to mycomputer:3000 instead of localhost:3000) and as long as the LiveReload port is accessible from the external machine, you'll connect and be LiveReloading away!

Which LiveReload script does it use?

• If you've got a LiveReload watcher running on the same machine as the app that responds to http://localhost:35729/livereload.js, that gets used, with the hostname being changed when injected into the HTML page.
• If you don't, the copy vendored with rack-livereload is used.
• You can force the use of either one (and save on the cost of checking to see if that file is available) with the middleware option :source => :vendored or :source => :livereload.

As usual, super-alpha!