Added 'watch'-mode to rebuild assets as they change

bin/evax

@@ -11,8 +11,19 @@ rescue LoadError
 end
 
 if ( ARGV.size < 2 )
-  Evax::Logger.log "use: $ evax <config_file_path> <relative_path>"
+  usage = "Usage:\n"\
+    "$ evax <config_file_path> <relative_path> [<options>]\n"\
+    "options:\n"\
+    "\t-w\t- watch assets for changes and rebuild when necessary"
+  Evax::Logger.log usage
   exit 1
 end
 
-Evax.new( ARGV[0], ARGV[1] ).build
+evax = Evax.new( ARGV[0], ARGV[1] )
+options = ARGV[2..-1]
+
+if options.include?("-w")
+  evax.run_as_daemon
+else
+  evax.run_once
+end

evax.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency "delorean",  "1.1.1"
 
   s.add_dependency "uglifier",  "1.2.3"
+  s.add_dependency "watchr",    "0.7"
 
   s.files         = `git ls-files`.split("\n")
   s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")

lib/evax.rb

@@ -1,5 +1,6 @@
 require "yaml"
 require "uglifier"
+require "watchr"
 
 require_relative "evax/version"
 require_relative "evax/css_minifier"
@@ -16,6 +17,14 @@ def initialize( config_file = "config/assets.yml", relative_path = "public/asset
     Evax::Logger.log "Relative Path: #{self.relative_path}"
   end
 
+  def run_once
+    build
+  end
+
+  def run_as_daemon
+    watch
+  end
+
   def config
     default_opts = { "compress" => true }
     default_opts.merge(YAML::load_file( @config_file ))
@@ -32,17 +41,30 @@ def build
     build_css if css_configured?
   end
 
-  def build_js
-    config["javascripts"].each_key do |group_name|
+  def watch
+    script = Watchr::Script.new
+    script.watch( asset_files_regex(:javascripts) ) {|asset| build_js( js_groups_for( asset[0] ) ) } if js_configured?
+    script.watch( asset_files_regex(:stylesheets) ) {|asset| build_css( css_groups_for( asset[0] ) ) } if css_configured?
+    Watchr::Controller.new( script, Watchr.handler.new ).run
+  end
+
+  def build_js( group_names=[] )
+    groups = config["javascripts"]
+    groups.select!{|k, v| group_names.include? k } if group_names.any?
+
+    groups.each_key do |group_name|
       result_string = join( :javascripts, group_name )
       result_string = Evax.compress_js( result_string ) if config["compress"]
 
       write_output( "#{group_name}.js", result_string )
     end
   end
 
-  def build_css
-    config["stylesheets"].each_key do |group_name|
+  def build_css( group_names=[] )
+    groups = config["stylesheets"]
+    groups.select!{|k, v| group_names.include? k } if group_names.any?
+
+    groups.each_key do |group_name|
       result_string = join( :stylesheets, group_name )
       result_string = Evax.compress_css( result_string ) if config["compress"]
 
@@ -79,4 +101,20 @@ def css_configured?
     !config["stylesheets"].nil?
   end
 
+  def asset_files_regex(type)
+    config[type.to_s].values.flatten.uniq.map {|path| Regexp.quote( path ) }.join( "|" )
+  end
+
+  def js_groups_for( file )
+    filter_groups_by_file( :javascripts, file )
+  end
+
+  def css_groups_for( file )
+    filter_groups_by_file( :stylesheets, file )
+  end
+
+  def filter_groups_by_file(type, file)
+    config[type.to_s].select {|k, v| v.include? file }.keys
+  end
+
 end

test/evax_test.rb

@@ -74,14 +74,21 @@ def test_write_output
     end
   end
 
-  def test_build_js
+  def test_build_js_all_groups
     evax = Evax.new( "#{FIXTURES}/assets.yml", "#{File.dirname(__FILE__)}/.." )
     evax.expects( :write_output ).with( "js_one.js", File.read( "#{FIXTURES}/js_one.compress.js" ) )
     evax.expects( :write_output ).with( "js_two.js", File.read( "#{FIXTURES}/js_two.compress.js" ) )
 
     evax.build_js
   end
 
+  def test_build_js_selected_groups
+    evax = Evax.new( "#{FIXTURES}/assets.yml", "#{File.dirname(__FILE__)}/.." )
+    evax.expects( :write_output ).with( "js_one.js", File.read( "#{FIXTURES}/js_one.compress.js" ) ).once
+
+    evax.build_js(["js_one"])
+  end
+
   def test_build_js_compress_off
     evax = Evax.new( "#{FIXTURES}/assets_compress_off.yml", "#{File.dirname(__FILE__)}/.." )
     Evax.expects( :compress_js ).never
@@ -91,14 +98,21 @@ def test_build_js_compress_off
     evax.build_js
   end
 
-  def test_build_css
+  def test_build_css_all_groups
     evax = Evax.new( "#{FIXTURES}/assets.yml", "#{File.dirname(__FILE__)}/.." )
     evax.expects( :write_output ).with( "css_one.css", File.read( "#{FIXTURES}/css_one.compress.css" ) )
     evax.expects( :write_output ).with( "css_two.css", File.read( "#{FIXTURES}/css_two.compress.css" ) )
 
     evax.build_css
   end
 
+  def test_build_css_selected_groups
+    evax = Evax.new( "#{FIXTURES}/assets.yml", "#{File.dirname(__FILE__)}/.." )
+    evax.expects( :write_output ).with( "css_one.css", File.read( "#{FIXTURES}/css_one.compress.css" ) ).once
+
+    evax.build_css(["css_one"])
+  end
+
   def test_build_css_off
     evax = Evax.new( "#{FIXTURES}/assets_compress_off.yml", "#{File.dirname(__FILE__)}/.." )
     Evax.expects( :compress_css ).never
@@ -134,4 +148,20 @@ def test_build
     evax.build
   end
 
+  def test_watch
+    evax = Evax.new( "#{FIXTURES}/assets.yml", "#{File.dirname(__FILE__)}/.." )
+    Watchr::Controller.any_instance.stubs(:run)
+
+    watchr = mock()
+    Watchr::Script.stubs(:new => watchr)
+    watchr.expects(:watch).with do |pattern, block|
+      pattern == "test/fixtures/javascripts/one\\.js|test/fixtures/javascripts/two\\.js|test/fixtures/javascripts/three\\.js|test/fixtures/javascripts/four\\.js"
+    end
+    watchr.expects(:watch).with do |pattern, block|
+      pattern == "test/fixtures/stylesheets/one\\.css|test/fixtures/stylesheets/two\\.css|test/fixtures/stylesheets/three\\.css|test/fixtures/stylesheets/four\\.css"
+    end
+
+    evax.watch
+  end
+
 end