add task to watch for changes on textile files and automatically generate the preview

misc/Gemfile

@@ -23,4 +23,5 @@ group :docs do
   gem 'github-markup', '~> 0.7.5', :require => 'github/markup'
   gem 'RedCloth', '~> 4.2.9'
   gem 'nokogiri', '~> 1.5.6'
+  gem 'filewatcher'
 end

misc/Gemfile.lock

@@ -25,6 +25,8 @@ GEM
     eventmachine (1.0.3)
     execjs (2.0.2)
     ffi (1.9.6)
+    filewatcher (0.3.4)
+      trollop (~> 2.0)
     github-markup (0.7.5)
     http_parser.rb (0.6.0)
     jasmine (1.3.2)
@@ -76,6 +78,7 @@ GEM
       daemons (>= 1.0.9)
       eventmachine (>= 0.12.6)
       rack (>= 1.0.0)
+    trollop (2.0)
     websocket (1.0.7)
 
 PLATFORMS
@@ -85,6 +88,7 @@ DEPENDENCIES
   RedCloth (~> 4.2.9)
   byebug (~> 1.3.1)
   em-http-request (~> 1.0.3)
+  filewatcher
   github-markup (~> 0.7.5)
   jasmine (~> 1.3.1)
   jshintrb (~> 0.2.1)

misc/Rakefile

-project_dir = File.expand_path('..', File.dirname(__FILE__))
-javascript_dir = File.expand_path(Dir["#{project_dir}/**/js"].first)
-
 require 'rubygems'
+require 'erb'
 
 # Set up gems listed in the Gemfile.
 ENV['BUNDLE_GEMFILE'] ||= File.expand_path('./Gemfile', File.dirname(__FILE__))
 require 'bundler/setup' if File.exists?(ENV['BUNDLE_GEMFILE'])
 Bundler.require(:default, :test) if defined?(Bundler)
 
+project_dir = File.expand_path('..', File.dirname(__FILE__))
+base_path = File.expand_path('pushstream/docs/preview', Dir.tmpdir)
+javascript_dir = File.expand_path(Dir["#{project_dir}/**/js"].first)
+
 begin
   require "rspec/core/rake_task"
 
@@ -88,28 +90,40 @@ begin
   Bundler.require(:default, :docs) if defined?(Bundler)
 
   task :get_static_files do
-    base_path = File.expand_path('pushstream/docs/preview', Dir.tmpdir)
     FileUtils.mkdir_p("#{base_path}/css")
 
     download_file("https://github.global.ssl.fastly.net/assets/github-f226abc7983f8566b17d24236adae64ba647ffea.css", "#{base_path}/css/github.css") unless File.exists?("#{base_path}/css/github.css")
     download_file("https://github.global.ssl.fastly.net/assets/github2-6edea06c20f02c9c2ae32842c7455d50c08c3f69.css", "#{base_path}/css/github2.css") unless File.exists?("#{base_path}/css/github2.css")
   end
 
-  desc "Generates docs files to preview."
-  task :generate => :get_static_files do
-    require 'erb'
+  def generate_preview_for(file, project_dir, base_path)
     template = ERB.new File.read("#{project_dir}/misc/github_template.html.erb")
-    base_path = File.expand_path('pushstream/docs/preview', Dir.tmpdir)
+    filename = File.basename(file)
+    content = GitHub::Markup.render(file, File.read(file))
+    rendered = template.result(binding)
+    output = File.expand_path(file.gsub(project_dir, "./"), base_path)
+    output_dir = File.dirname(output)
+    FileUtils.mkdir_p(output_dir)
+    File.open(output, 'w') {|f| f.write(rendered) }
+    puts "Preview rendered to #{output}"
+  end
 
+  desc "Generates docs files to preview."
+  task :generate => :get_static_files do
     Dir.glob("#{project_dir}/**/*.textile").each do |file|
-      filename = File.basename(file)
-      content = GitHub::Markup.render(file, File.read(file))
-      rendered = template.result(binding)
-      output = file.gsub(project_dir, File.expand_path('pushstream/docs/preview', Dir.tmpdir))
-      output_dir = File.dirname(output)
-      FileUtils.mkdir_p(output_dir)
-      File.open(output, 'w') {|f| f.write(rendered) }
-      puts "Preview rendered to #{output}"
+      generate_preview_for(file, project_dir, base_path)
+    end
+  end
+
+  desc "Watch for changes on doc to generate the preview."
+  task :watch do
+    puts "watching for changes on textile files"
+    Dir.chdir(project_dir) do
+      FileWatcher.new(["*.textile"]).watch do |file, event|
+        if(event != :delete)
+          generate_preview_for(file, project_dir, base_path)
+        end
+      end
     end
   end