Merge pull request #430 from reactjs/support-asset-manifest

Fix(SprocketsRenderer) support Sprockets::Manifest if assets were precompiled

Author: Robert Mosolgo

lib/react/server_rendering/environment_container.rb

@@ -0,0 +1,18 @@
+module React
+  module ServerRendering
+    # Return asset contents by getting them from a Sprockets::Environment instance.
+    #
+    # This is good for Rails development but bad for production because:
+    # - It compiles the asset lazily, not ahead-of-time
+    # - Rails 5 / Sprockets 3 doesn't expose a Sprockets::Environment in production.
+    class EnvironmentContainer
+      def initialize
+        @environment = ::Rails.application.assets
+      end
+
+      def find_asset(logical_path)
+        @environment[logical_path].to_s
+      end
+    end
+  end
+end

lib/react/server_rendering/exec_js_renderer.rb

@@ -1,9 +1,9 @@
-# A bare-bones renderer for React.js + Exec.js
-# - Depends on global ReactDOMServer in the ExecJS context
-# - No Rails dependency
-# - No browser concerns
 module React
   module ServerRendering
+    # A bare-bones renderer for React.js + Exec.js
+    # - Depends on global ReactDOMServer in the ExecJS context
+    # - No Rails dependency
+    # - No browser concerns
     class ExecJSRenderer
       def initialize(options={})
         js_code = options[:code] || raise("Pass `code:` option to instantiate a JS context!")

lib/react/server_rendering/manifest_container.rb

@@ -0,0 +1,19 @@
+module React
+  module ServerRendering
+    # Get asset content by reading the compiled file from disk using a Sprockets::Manifest.
+    #
+    # This is good for Rails production when assets are compiled to public/assets
+    # but sometimes, they're compiled to other directories (or other servers)
+    class ManifestContainer
+      def initialize
+        @manifest = ::Rails.application.assets_manifest
+      end
+
+      def find_asset(logical_path)
+        asset_path = @manifest.assets[logical_path] || raise("No compiled asset for #{logical_path}, was it precompiled?")
+        asset_full_path = ::Rails.root.join("public", @manifest.directory, asset_path)
+        File.read(asset_full_path)
+      end
+    end
+  end
+end

lib/react/server_rendering/sprockets_renderer.rb

@@ -1,9 +1,11 @@
-# Extends ExecJSRenderer for the Rails environment
-# - builds JS code out of the asset pipeline
-# - stringifies props
-# - implements console replay
+require "react/server_rendering/environment_container"
+require "react/server_rendering/manifest_container"
 module React
   module ServerRendering
+    # Extends ExecJSRenderer for the Rails environment
+    # - builds JS code out of the asset pipeline
+    # - stringifies props
+    # - implements console replay
     class SprocketsRenderer < ExecJSRenderer
       # Reimplement console methods for replaying on the client
       CONSOLE_POLYFILL = File.read(File.join(File.dirname(__FILE__), "sprockets_renderer/console_polyfill.js"))
@@ -15,7 +17,7 @@ def initialize(options={})
         js_code = CONSOLE_POLYFILL.dup
 
         filenames.each do |filename|
-          js_code << ::Rails.application.assets[filename].to_s
+          js_code << asset_container.find_asset(filename)
         end
 
         super(options.merge(code: js_code))
@@ -39,6 +41,30 @@ def render(component_name, props, prerender_options)
       def after_render(component_name, props, prerender_options)
         @replay_console ? CONSOLE_REPLAY : ""
       end
+
+      class << self
+        attr_accessor :asset_container_class
+      end
+
+      # Get an object which exposes assets by their logical path.
+      #
+      # Out of the box, it supports a Sprockets::Environment (application.assets)
+      # and a Sprockets::Manifest (application.assets_manifest), which covers the
+      # default Rails setups.
+      #
+      # You can provide a custom asset container
+      # with `React::ServerRendering::SprocketsRender.asset_container_class = MyAssetContainer`.
+      #
+      # @return [#find_asset(logical_path)] An object that returns asset contents by logical path
+      def asset_container
+        @asset_container ||= if self.class.asset_container_class.present?
+          self.class.asset_container_class.new
+        elsif ::Rails.application.config.assets.compile
+          EnvironmentContainer.new
+        else
+          ManifestContainer.new
+        end
+      end
     end
   end
 end

test/react/server_rendering/manifest_container_test.rb

@@ -0,0 +1,28 @@
+require "test_helper"
+
+# Rails 3.x doesn't have `application.assets_manifest=`
+# I don't think we have to support Rails 3 + Sprockets 3 anyways!
+if Rails::VERSION::MAJOR > 3
+  class ManifestContainerTest < ActiveSupport::TestCase
+    def setup
+      precompile_assets
+
+      # Make a new manifest since assets weren't compiled before
+      config = Rails.application.config
+      path = File.join(config.paths['public'].first, config.assets.prefix)
+      new_manifest = Sprockets::Manifest.new(Rails.application.assets, path)
+      Rails.application.assets_manifest = new_manifest
+
+      @manifest_container = React::ServerRendering::ManifestContainer.new
+    end
+
+    def teardown
+      clear_precompiled_assets
+    end
+
+    def test_find_asset_gets_asset_contents
+      application_js_content = @manifest_container.find_asset("application.js")
+      assert(application_js_content.length > 50000, "It's the compiled file")
+    end
+  end
+end

test/react_test.rb

@@ -26,12 +26,9 @@ class ReactTest < ActionDispatch::IntegrationTest
 
   test 'precompiling assets works' do
     begin
-      ENV['RAILS_GROUPS'] = 'assets' # required for Rails 3.2
-      Dummy::Application.load_tasks
-      Rake::Task['assets:precompile'].invoke
-      FileUtils.rm_r(File.expand_path("../dummy/public/assets", __FILE__))
+      precompile_assets
     ensure
-      ENV.delete('RAILS_GROUPS')
+      clear_precompiled_assets
     end
   end
 

test/test_helper.rb

@@ -39,6 +39,18 @@ def manually_expire_asset(asset_name)
   def asset.fresh?(env); false; end
 end
 
+def precompile_assets
+  ENV['RAILS_GROUPS'] = 'assets' # required for Rails 3.2
+  Dummy::Application.load_tasks
+  Rake::Task['assets:precompile'].reenable
+  Rake::Task['assets:precompile'].invoke
+end
+
+def clear_precompiled_assets
+  FileUtils.rm_r(File.expand_path("../dummy/public/assets", __FILE__))
+  ENV.delete('RAILS_GROUPS')
+end
+
 # Load support files
 Dir["#{File.dirname(__FILE__)}/support/**/*.rb"].each { |f| require f }