"livereload" server replacement for working with Rails

_notes.md

A replacement for "livereload" gem on OS X

This script is a replacement for livereload server component designed for working with Rails. It watches the filesystem with FS Events (Mac OS X) rather than with EventMachine. This is better for large projects for wich EventMachine fails with "too many open files" exception.

Sass is supported; .sass files can also be stored in "app/styles/" directory. Compass is detected if "config/compass.rb" file exists.

Installation:

Download this script to somewhere in your PATH and make it executable. You can name it something different than "livereload" if you want to try this and the official gem executable in parallel.

Then, visit the official livereload project for instructions on how to install the browser component.

Details

1. .erb and .haml templates under "app/": page reload
2. .rb files under "app/helpers/": page reload
3. .html and .js files under "public/": page reload
4. .css files under "public/": live style update!
5. .sass and .scss files anywhere: compile to CSS

Command line options are "-D" to enable debug mode. All other parameters (if given) specify a list of directories to watch. This is not compatible with livereload gem, which supports many more options and customization. If you want customization, edit this script. It's simple.

livereload.rb

#!/usr/bin/ruby -rubygems

# Replacement for "livereload" gem for working with Rails
#
# Dependencies:
#   $ sudo /usr/bin/gem install mislav-rspactor em-websocket json haml

# uncomment to force loading the correct rspactor version
# gem 'mislav-rspactor', '~> 0.4.0'
require 'rspactor'
require 'em-websocket'
require 'json'
require 'sass/plugin'
require 'fileutils'

API_VERSION = '1.3'

web_sockets = []
debug = !!ARGV.delete('-D')
dirs = ARGV.empty?? [Dir.pwd] : ARGV

# Compass support
compass_config = "./config/compass.rb"

if File.exists? compass_config
  # $ sudo /usr/bin/gem install compass
  require 'compass'
  Compass.add_project_configuration(compass_config)
  Compass.configure_sass_plugin!
  Compass.handle_configuration_change!
else
  Sass::Plugin.add_template_location(Dir.pwd + '/app/styles')
end

# Jekyll support
jekyll_mode = %w[_config.yml _site].any? { |file| File.exists? file }

if jekyll_mode
  require 'jekyll'
  require 'webrick'
  
  options = Jekyll.configuration({})
  # Get source and destination directories (possibly set by config file)
  source      = options['source']
  destination = options['destination']
  # Create the Site
  jekyll_site = Jekyll::Site.new(options)
  
  FileUtils.mkdir_p(destination)

  mime_types = WEBrick::HTTPUtils::DefaultMimeTypes
  mime_types.store 'js', 'application/javascript'

  jekyll_server = WEBrick::HTTPServer.new(
    :Port         => options['server_port'],
    :DocumentRoot => destination,
    :MimeTypes    => mime_types
  )
end

sinatra_mode = File.exists? 'app.rb'

extensions = %w[html erb haml sass scss css js rb yml]
extensions.concat %w[md markdown textile xml] if jekyll_mode
extensions << 'mustache' if sinatra_mode

ws_push = lambda do |file|
  data = ['refresh', { :path => file, :apply_js_live  => false, :apply_css_live => true }].to_json
  puts data if debug
  # send it to the browser!
  web_sockets.each { |ws| ws.send(data) }
end

process_file = if sinatra_mode
  lambda do |file|
    case file
    when %r{/(views|templates)/}, %r{/public/.+\.(css|js|html)$}
      file = file.sub(%r{\.s[ac]ss$}, '.css')
      ws_push[file]
      true
    else
      false
    end
  end
else
  lambda do |file|
    case file
    when %r{/app/.+\.(erb|haml)$}, %r{/app/helpers/.+\.rb$}, # application view code
        %r{/public/.+\.(css|js|html)$}, # static assets
        %r{/config/locales/.+\.yml$}, # translation files
        %r{/_site/.+\.css$} # styles in jekyll
      ws_push[file]
      true
    when %r{\.s[ac]ss$}
      puts "Regenerating CSS stylesheets..." if debug
      Sass::Plugin.update_stylesheets
      true
    else
      false
    end
  end
end

listener = RSpactor::Listener.new(:extensions => extensions, :relative_paths => false) { |files|
  for file in files
    done = process_file[file]
    puts "Unhandled change: #{file}" if not done and debug and not jekyll_mode
  end
  
  if jekyll_mode and not files.any? { |file| file.index(destination) == 0 }
    # puts "Regenerating site..."
    # jekyll_site.process
    
    files.select { |file| file =~ /\.css/ }.each do |file|
      path = file.sub(Dir.pwd + '/', '')
      target_file = File.expand_path(path, destination)
      listener.force_changed << target_file
      FileUtils.cp file, target_file
    end
  end
}

Sass::Plugin.on_updating_stylesheet do |template, css|
  # We notify the listener that the stylesheet file changed for sure.
  # Because the filesystem can't know modification time in milliseconds,
  # this prevents FSEvents handler from thinking the file didn't change.
  stylesheet_file = File.expand_path(css, Dir.pwd)
  puts "generating #{stylesheet_file}" if debug
  listener.force_changed << stylesheet_file
end

Sass::Plugin.on_compilation_error do |e, template, css|
  warn "error compiling #{template}"
end

puts "Starting file watcher for directories: #{dirs.inspect}"
listener.start(dirs)

# Disable the RubyCocoa thread hook as apparently Laurent did not apply the
# thread patches to the OS X system Ruby
ENV['RUBYCOCOA_THREAD_HOOK_DISABLE'] = 'kampai'

Thread.new { OSX.CFRunLoopRun }

if jekyll_mode
  Thread.new { jekyll_server.start }
  trap("INT") { jekyll_server.shutdown }
end

trap("INT") { EventMachine.stop }

EventMachine.run do
  puts "LiveReload is waiting for a browser to connect."
  EventMachine::WebSocket.start(:host => '0.0.0.0', :port => '10083', :debug => debug) do |ws|
    ws.onopen do
      begin
        puts "Browser connected."
        ws.send "!!ver:#{API_VERSION}"
        web_sockets << ws
      rescue
        puts $!
        puts $!.backtrace
      end
    end
  
    ws.onmessage do |msg|
      puts "Browser URL: #{msg}"
    end
  
    ws.onclose do
      web_sockets.delete ws
      puts "Browser disconnected."
    end
  end
end

@andreyvit Have you look how RSpactor (http://github.com/thibaudgg/rspactor) handle FSEvents (without RubyCocoa & EM) ? Feel free to contact me if you have any questions.

Thanks mislav, works like a charm. How about wrapping it up into a gem, or possibly merging it with livereload?