feat(ServerRendering) add end-to-end test of per-request prerenderer

Author: rmosolgo

Appraisals

@@ -43,11 +43,17 @@ appraise "rails-4.2-sprockets_4" do
   gem 'rails', '~> 4.2.1'
   gem "sprockets", "~> 4.0.x"
   gem "turbolinks", "~> 2.5.0"
+  # This ExecJS backend provides stateful context
+  # which the default nodejs backend does not
+  gem "mini_racer"
 end
 
 appraise "rails-5" do
   gem 'rails', '~> 5.0.0'
   gem "turbolinks", "~> 5.0.0"
+  # This ExecJS backend provides stateful context
+  # which the default nodejs backend does not
+  gem "therubyracer"
 end
 
 appraise "rails-5-no_sprockets" do

gemfiles/rails_3.2.gemfile

@@ -2,8 +2,8 @@
 
 source "http://rubygems.org"
 
+gem "turbolinks", "~> 2.0"
 gem "rails", "~> 3.2.21"
 gem "rack-cache", "~> 1.6.1"
-gem "turbolinks", "~> 2.0"
 
 gemspec :path => "../"

gemfiles/rails_4.0.5.gemfile

@@ -2,7 +2,7 @@
 
 source "http://rubygems.org"
 
-gem "rails", "4.0.5"
 gem "turbolinks"
+gem "rails", "4.0.5"
 
 gemspec :path => "../"

gemfiles/rails_4.0_with_therubyracer.gemfile

@@ -2,8 +2,8 @@
 
 source "http://rubygems.org"
 
+gem "turbolinks"
 gem "rails", "~> 4.0.13"
 gem "therubyracer", "0.12.0", :platform => :mri
-gem "turbolinks"
 
 gemspec :path => "../"

gemfiles/rails_4.1.gemfile

@@ -2,7 +2,7 @@
 
 source "http://rubygems.org"
 
-gem "rails", "~> 4.1.10"
 gem "turbolinks", "~> 2.3.0"
+gem "rails", "~> 4.1.10"
 
 gemspec :path => "../"

gemfiles/rails_4.2_sprockets_2.gemfile

@@ -2,8 +2,8 @@
 
 source "http://rubygems.org"
 
+gem "turbolinks"
 gem "rails", "~> 4.2.1"
 gem "sprockets", "~> 2.12"
-gem "turbolinks"
 
 gemspec :path => "../"

gemfiles/rails_4.2_sprockets_3.gemfile

@@ -2,8 +2,8 @@
 
 source "http://rubygems.org"
 
+gem "turbolinks", "~> 2.5.0"
 gem "rails", "~> 4.2.1"
 gem "sprockets", "~> 3.5"
-gem "turbolinks", "~> 2.5.0"
 
 gemspec :path => "../"

gemfiles/rails_4.2_sprockets_4.gemfile

@@ -2,8 +2,9 @@
 
 source "http://rubygems.org"
 
+gem "turbolinks", "~> 2.5.0"
 gem "rails", "~> 4.2.1"
 gem "sprockets", "~> 4.0.x"
-gem "turbolinks", "~> 2.5.0"
+gem "mini_racer"
 
 gemspec :path => "../"

gemfiles/rails_5.gemfile

@@ -2,7 +2,8 @@
 
 source "http://rubygems.org"
 
-gem "rails", "~> 5.0.0"
 gem "turbolinks", "~> 5.0.0"
+gem "rails", "~> 5.0.0"
+gem "therubyracer"
 
 gemspec :path => "../"

gemfiles/rails_5_no_sprockets.gemfile

@@ -2,6 +2,7 @@
 
 source "http://rubygems.org"
 
+gem "turbolinks"
 gem "rails", "~> 5.0.0"
 
 gemspec :path => "../"

gemfiles/rails_5_sprockets_4.gemfile

@@ -2,8 +2,8 @@
 
 source "http://rubygems.org"
 
+gem "turbolinks", "~> 5.0.0"
 gem "rails", "~> 5.0.0"
 gem "sprockets", "~> 4.0.x"
-gem "turbolinks", "~> 5.0.0"
 
 gemspec :path => "../"

test/dummy/app/assets/javascripts/components.js

@@ -1,2 +1,3 @@
 //= require_self
 //= require_tree ./components
+//= require ./pages

test/dummy/app/assets/javascripts/pages.js

@@ -1,6 +1,13 @@
 var GreetingMessage = React.createClass({
   getInitialState: function() {
-    return {greeting: 'Hello'};
+    var initialGreeting = 'Hello';
+    if (typeof global !== "undefined" && global.ctx && global.ctx.greeting) {
+      initialGreeting = global.ctx.greeting
+    }
+
+    return {
+      greeting: initialGreeting
+    }
   },
   goodbye: function() {
     this.setState({greeting: 'Goodbye'});

test/dummy/app/controllers/pages_controller.rb

@@ -1,5 +1,19 @@
 class PagesController < ApplicationController
+  around_action :per_request_react_prerenderer
+
   def show
+    @prerender = !!params[:prerender]
+    if @prerender
+      js_context = __prerenderer.context
+      # This isn't safe for production, we're just testing the render context:
+      greeting_override = params[:greeting] || ""
+      setup_code = "global.ctx = {}; global.ctx.greeting = '#{greeting_override}';"
+      js_context.exec(setup_code)
+    end
     @name = %w(Alice Bob)[params[:id].to_i % 2]
+    render :show
+    if @prerender
+      js_context.exec("global.ctx = undefined;")
+    end
   end
 end

test/dummy/app/views/pages/show.html.erb

@@ -4,7 +4,7 @@
 </ul>
 
 <div id='component-parent'>
-  <%= react_component 'GreetingMessage', { :name => @name }, { :id => 'component' } %>
+  <%= react_component 'GreetingMessage', { :name => @name }, { :id => 'component', prerender: @prerender } %>
 </div>
 
 <button onClick="ReactRailsUJS.unmountComponents('#component-parent')">Unmount by parent selector</button>

test/react/rails/pages_controller_test.rb

@@ -5,4 +5,20 @@ class PagesControllerTest < ActionController::TestCase
     get :show, id: 1
     assert_equal(200, response.status)
   end
+
+  when_stateful_js_context_available do
+    test "it sets up and tears down a react context" do
+      get :show, id: 1, prerender: true
+      assert_includes(response.body, "Hello")
+
+      get :show, id: 1, prerender: true, greeting: "Howdy"
+      assert_includes(response.body, "Howdy")
+
+      get :show, id: 1, prerender: true, greeting: "👋"
+      assert_includes(response.body, "👋")
+
+      get :show, id: 1, prerender: true
+      assert_includes(response.body, "Hello")
+    end
+  end
 end

test/test_helper.rb

@@ -129,3 +129,9 @@ def assert_compiled_javascript_matches(javascript, expectation)
 def assert_compiled_javascript_includes(javascript, expected_part)
   assert_includes javascript.gsub(/\s/, ''), expected_part.gsub(/\s/, '')
 end
+
+def when_stateful_js_context_available
+  if defined?(V8) || defined?(MiniRacer)
+    yield
+  end
+end