"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

What version of rspactor are you using? I'm on 0.6.4 and get

livereload:65: undefined method start' for #<RSpactor::Listener:0x1011887b8> (NoMethodError) from /Users/will/.rvm/gems/ree-1.8.7-2010.02/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:incall'
from /Users/will/.rvm/gems/ree-1.8.7-2010.02/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in run_machine' from /Users/will/.rvm/gems/ree-1.8.7-2010.02/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:inrun'
from script/livereload:40

No, I'm using my fork which I published as "mislav-rspactor" gem. I've indicated this in the instructions. I've updated the comments with a gem command you can use to explicitly state which gem you want to use.

Great, I'll add this to RSpactor 0.7! Do you thing debug option is needed?

Oh! btw no more rubycocoa dependency with RSpactor 0.7 ;-)

I know, I've been following. But wasn't it reverted?

About this in rspactor: I don't think it's rspactor material. I'd rather publish it as a fork of livereload ('cause that's what it is)

Ah, I see now what you meant about fsevent_watch. Interesting stuff. I'll try 0.7, maybe even merge some of my own ideas into it. But for now, I'm sticking to my forks of both livereload and rspactor. When my livereload gets more solid (meaning tested against real world projects) we can think about having it in rspactor.

having this livereload stuff in rspactor itself would be amazing

But this:

Thread.new { OSX.CFRunLoopRun }

requires Ruby 1.9, right?

Nope. Because this requires system ruby on OS X, it can obviously only run on 1.8.7 which is installed with Snow Leopard. Might work 1.8.6 in Leopard too.

Trying to understand the reason for this exactly.

Thread.new { OSX.CFRunLoopRun }

Is this for rspactor before 0.7 when RubyCocoa was required?

Yes, this code depends on my fork of rspactor which is still bound to RubyCocoa. Notice that I used "/usr/bin/ruby" in installation instructions and in the shebang.

My fork of rspactor is soon going independent of RubyCocoa, and it will even run on Linux. I cherry picked this functionality from the official fork and improved it, but I haven't tested and released yet.

Just updated with extra mappings and experimental Compass support.

Compass support works great. I had to add in my own require for fancy-buttons since that was in my compass initializer. But other than that, it's working perfectly.

Info for the guys (and girls) using this alternate tool: LiveReload 1.4 should now work with large projects, check it out. Also you are encouraged to open issues on github.com/mockko/livereload/issues for any functionality you miss in the official LiveReload gem.

@mislav, we're very much interested in allowing integration of LiveReload with other tools without just copying/rewriting the server code. Please let us know what we can do to enable that.

Also,

Thread.new { OSX.CFRunLoopRun }

gives a warning from Ruby 1.8.7 that you can't use threads in RubyCocoa. Depending on some random condition the application either crashes or continues working after that. Our em-dir-watcher gem forks a subprocess instead.

[UPDATE] OK, I see this code — thanks a lot for the pointer, maybe we'll use it:

# 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'

@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?