Merge pull request #48 from jwhitley/issue/48

Support for CDN hosted assets

Author: jwhitley

CHANGELOG.md

@@ -1,3 +1,9 @@
+# v0.8.0
+
+- Build will now substitute `empty:` for the right-hand side of
+  `config/requirejs.yml` paths entries that are URLs.
+- Documented how to configure assets hosted on a CDN.
+
 # v0.7.3
 
 - Upgrade RequireJS and r.js to v1.0.8

README.md

@@ -186,6 +186,38 @@ This will generate a script tag like so:
 <script data-main="/assets/page1.js" data-foo="..." data-bar="..." src="/assets/require.js"></script>
 ```
 
+### External domain (CDN) support
+
+There are two ways in which requirejs-rails supports the use of different
+domains for serving built JavaScript modules, as is the case when using
+a [CDN](http://en.wikipedia.org/wiki/Content_delivery_network).
+
+1.  URLs in paths config in `requirejs.yml`:
+
+    If requirejs-rails encounters an URL as the right-hand side of a paths
+    configuration, it will correctly emit that as `"empty:"` during the build
+    process so that [r.js will do the right thing](http://requirejs.org/docs/optimization.html#empty).
+
+    Example:
+
+    ```yaml
+    paths:
+      jquery: "https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"
+    ```
+
+2.  Deploying all requirejs-rails assets to a CDN:
+
+    In `config/environments/production.rb` (or another environment)
+    set the run_config as follows:
+
+    ```ruby
+    config.requirejs.run_config['baseUrl'] = 'http://mycdn.example.com/12345abc/assets'
+    ```
+
+    The [`asset_sync` gem](https://github.com/rumblelabs/asset_sync) is one
+    tool that can be used to deploy your built assets to a CDN (S3, in this
+    case).
+
 ## Troubleshooting
 
 ### Avoid `config.assets.precompile`
@@ -196,7 +228,9 @@ javascript_include_tag, and which is **never** referenced by the AMD codebase.
 
 ## Using AMD libraries
 
-I currently recommend placing your AMD libraries into `vendor/assets/javascripts`.  The needs of a few specific libraries are discussed below.
+I currently recommend placing your AMD libraries into
+`vendor/assets/javascripts`.  The needs of a few specific libraries are
+discussed below.
 
 ### jQuery
 

app/helpers/requirejs_helper.rb

@@ -54,7 +54,10 @@ def requirejs_include_tag(name=nil, &block)
           paths = {}
           modules.each { |m| paths[m] = _javascript_path(m).sub /\.js$/,'' }
 
-          # Override uesr paths, whose mappings are only relevant in dev mode
+          # Add paths for assets specified by full URL (on a CDN)
+          run_config['paths'].each { |k,v| paths[k] = v if v =~ /^https?:/ }
+
+          # Override user paths, whose mappings are only relevant in dev mode
           # and in the build_config.
           run_config['paths'] = paths
         end

lib/requirejs/rails/config.rb

@@ -108,13 +108,17 @@ def build_config
           mod['name'] = 'almond'
           mod['include'] = name
         end
+        self.rewrite_urls_in_paths self[:build_config]
       end
       self[:build_config]
     end
 
     def run_config
-      run_config = { "baseUrl" => "/assets" }
-      run_config.merge!(self.user_config).slice(*self.run_config_whitelist)
+      unless self.has_key?(:run_config)
+        self[:run_config] = { "baseUrl" => "/assets" }
+        self[:run_config].merge!(self.user_config).slice!(*self.run_config_whitelist)
+      end
+      self[:run_config]
     end
 
     def user_config=(cfg)
@@ -146,5 +150,13 @@ def asset_allowed?(asset)
         accum || (matcher =~ asset)
       end ? true : false
     end
+
+    def rewrite_urls_in_paths(cfg)
+      if cfg.has_key? 'paths'
+        cfg['paths'] = cfg['paths'].each_with_object({}) do |(k, v), h|
+          h[k] = (v =~ /^https?:/) ? 'empty:' : v
+        end
+      end
+    end
   end
 end

test/requirejs-rails_test.rb

@@ -51,7 +51,7 @@ def setup
 
   test "user_config should reject baseUrl" do
     exc = assert_raises Requirejs::ConfigError do
-      @cfg.user_config = { "baseUrl" => "/frobnitz" }
+      @cfg.user_config = { 'baseUrl' => '/frobnitz' }
     end
     assert_match /baseUrl is not needed/, exc.message
   end
@@ -63,6 +63,11 @@ def setup
     assert_equal 'lib/jquery-1.7.2.min', @cfg.run_config['paths']['jquery']
   end
 
+  test "run_config should allow settings to be overridden" do
+    @cfg.run_config['baseUrl'] = 'http://cdn.example.com/assets'
+    assert_equal 'http://cdn.example.com/assets', @cfg.run_config['baseUrl']
+  end
+
   test "build_config should inherit user_config settings" do
     @cfg.user_config = { 'paths' => { 'jquery' => 'lib/jquery-1.7.2.min' } }
     refute_nil @cfg.build_config['paths']
@@ -80,7 +85,27 @@ def setup
     assert_nil @cfg.build_config['priority'] 
   end
 
-  ## Almond tests
+  test "build config should replace urls in paths with 'empty:'" do
+    @cfg.user_config = { 'paths' => 
+      { 
+        'jquery' => 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js',
+        'jqueryssl' => 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js'
+      }
+    }
+    assert_equal 'empty:', @cfg.build_config['paths']['jquery']
+    assert_equal 'empty:', @cfg.build_config['paths']['jqueryssl']
+  end
+
+  test "build_config should not modify non-urls in paths" do
+    @cfg.user_config = { 'paths' => 
+      { 
+        'foo' => 'components/foo'
+      }
+    }
+    assert_equal 'components/foo', @cfg.build_config['paths']['foo']
+  end
+
+  ## Almond-specific tests
   test "build_config with almond should accept one module" do
     @cfg.loader = :almond
     @cfg.user_config = { 'modules' => [ { 'name' => 'foo' } ] }
@@ -101,6 +126,10 @@ class RequirejsHelperTest < ActionView::TestCase
 
   def setup
     controller.requirejs_included = false
+    Rails.application.config.requirejs.user_config = { 'paths' => 
+      { 'jquery' => 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js' }
+    }
+
   end
 
   def wrap(tag)
@@ -133,4 +162,20 @@ def wrap(tag)
       render :text => "#{requirejs_include_tag}\n#{requirejs_include_tag}"
     end
   end
+
+  test "requirejs_include_tag with CDN asset in paths" do
+    render :text => wrap(requirejs_include_tag)
+    assert_select "script:first-of-type", :text => %r{var require =.*paths.*http://ajax}
+  end
+
+  test "requirejs_include_tag with CDN asset and digested asset paths" do
+    begin
+      saved_digest = Rails.application.config.assets.digest
+      Rails.application.config.assets.digest = true
+      render :text => wrap(requirejs_include_tag)
+      assert_select "script:first-of-type", :text => %r{var require =.*paths.*http://ajax}
+    ensure
+      Rails.application.config.assets.digest = saved_digest
+    end
+  end
 end