Add mailer previews feature based on mail_view gem

actionmailer/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Add mailer previews feature based on 37 Signals mail_view gem
+
+    *Andrew White*
+
 *   Calling `mail()` without arguments serves as getter for the current mail
     message and keeps previously set headers.
 

actionmailer/lib/action_mailer.rb

@@ -41,6 +41,8 @@ module ActionMailer
   autoload :Base
   autoload :DeliveryMethods
   autoload :MailHelper
+  autoload :Preview
+  autoload :Previews, 'action_mailer/preview'
   autoload :TestCase
   autoload :TestHelper
 end

actionmailer/lib/action_mailer/base.rb

@@ -308,6 +308,25 @@ module ActionMailer
   # Note that unless you have a specific reason to do so, you should prefer using before_action
   # rather than after_action in your ActionMailer classes so that headers are parsed properly.
   #
+  # = Previewing emails
+  #
+  # You can preview your email templates visually by adding a mailer preview file to the
+  # <tt>ActionMailer::Base.preview_path</tt>. Since most emails do something interesting
+  # with database data, you'll need to write some scenarios to load messages with fake data:
+  #
+  #   class NotifierPreview < ActionMailer::Preview
+  #     def welcome
+  #       Notifier.welcome(User.first)
+  #     end
+  #   end
+  #
+  # Methods must return a Mail::Message object which can be generated by calling the mailer
+  # method without the additional <tt>deliver</tt>. The location of the mailer previews
+  # directory can be configured using the <tt>preview_path</tt> option which has a default
+  # of <tt>test/mailers/previews</tt>:
+  #
+  #     config.action_mailer.preview_path = "#{Rails.root}/lib/mailer_previews"
+  #
   # = Configuration options
   #
   # These options are specified on the class level, like
@@ -362,6 +381,7 @@ module ActionMailer
   #   <tt>delivery_method :test</tt>. Most useful for unit and functional testing.
   class Base < AbstractController::Base
     include DeliveryMethods
+    include Previews
 
     abstract!
 

actionmailer/lib/action_mailer/preview.rb

@@ -0,0 +1,67 @@
+require 'active_support/descendants_tracker'
+
+module ActionMailer
+  module Previews #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      # Set the location of mailer previews through app configuration:
+      #
+      #     config.action_mailer.preview_path = "#{Rails.root}/lib/mailer_previews"
+      #
+      class_attribute :preview_path, instance_writer: false
+    end
+  end
+
+  class Preview
+    extend ActiveSupport::DescendantsTracker
+
+    class << self
+      # Returns all mailer preview classes
+      def all
+        load_previews if descendants.empty?
+        descendants
+      end
+
+      # Returns the mail object for the given email name
+      def call(email)
+        preview = self.new
+        preview.public_send(email)
+      end
+
+      # Returns all of the available email previews
+      def emails
+        public_instance_methods(false).map(&:to_s).sort
+      end
+
+      # Returns true if the email exists
+      def email_exists?(email)
+        emails.include?(email)
+      end
+
+      # Returns true if the preview exists
+      def exists?(preview)
+        all.any?{ |p| p.preview_name == preview }
+      end
+
+      # Find a mailer preview by its underscored class name
+      def find(preview)
+        all.find{ |p| p.preview_name == preview }
+      end
+
+      # Returns the underscored name of the mailer preview without the suffix
+      def preview_name
+        name.sub(/Preview$/, '').underscore
+      end
+
+      protected
+        def load_previews #:nodoc:
+          Dir["#{preview_path}/**/*_preview.rb"].each{ |file| require_dependency file }
+        end
+
+        def preview_path #:nodoc:
+          Base.preview_path
+        end
+    end
+  end
+end

actionmailer/lib/action_mailer/railtie.rb

@@ -40,5 +40,13 @@ class Railtie < Rails::Railtie # :nodoc:
         config.compile_methods! if config.respond_to?(:compile_methods!)
       end
     end
+
+    initializer "action_mailer.configure_mailer_previews", before: :set_autoload_paths do |app|
+      if Rails.env.development?
+        options = app.config.action_mailer
+        options.preview_path ||= defined?(Rails.root) ? "#{Rails.root}/test/mailers/previews" : nil
+        app.config.autoload_paths << options.preview_path
+      end
+    end
   end
 end

actionpack/lib/action_dispatch/routing/inspector.rb

@@ -69,7 +69,7 @@ def action
       end
 
       def internal?
-        controller.to_s =~ %r{\Arails/(info|welcome)} || path =~ %r{\A#{Rails.application.config.assets.prefix}}
+        controller.to_s =~ %r{\Arails/(info|mailers|welcome)} || path =~ %r{\A#{Rails.application.config.assets.prefix}}
       end
 
       def engine?

railties/lib/rails.rb

@@ -25,6 +25,7 @@ module Rails
 
   autoload :Info
   autoload :InfoController
+  autoload :MailersController
   autoload :WelcomeController
 
   class << self

railties/lib/rails/application/finisher.rb

@@ -22,6 +22,8 @@ module Finisher
       initializer :add_builtin_route do |app|
         if Rails.env.development?
           app.routes.append do
+            get '/rails/mailers'         => "rails/mailers#index"
+            get '/rails/mailers/*path'   => "rails/mailers#preview"
             get '/rails/info/properties' => "rails/info#properties"
             get '/rails/info/routes'     => "rails/info#routes"
             get '/rails/info'            => "rails/info#index"

railties/lib/rails/generators/test_unit/mailer/mailer_generator.rb

@@ -4,11 +4,18 @@ module TestUnit # :nodoc:
   module Generators # :nodoc:
     class MailerGenerator < Base # :nodoc:
       argument :actions, type: :array, default: [], banner: "method method"
-      check_class_collision suffix: "Test"
+
+      def check_class_collision
+        class_collisions "#{class_name}Test", "#{class_name}Preview"
+      end
 
       def create_test_files
         template "functional_test.rb", File.join('test/mailers', class_path, "#{file_name}_test.rb")
       end
+
+      def create_preview_files
+        template "preview.rb", File.join('test/mailers/previews', class_path, "#{file_name}_preview.rb")
+      end
     end
   end
 end

railties/lib/rails/generators/test_unit/mailer/templates/preview.rb

@@ -0,0 +1,11 @@
+<% module_namespacing do -%>
+class <%= class_name %>Preview < ActionMailer::Preview
+<% actions.each do |action| -%>
+
+  def <%= action %>
+    <%= class_name %>.<%= action %>
+  end
+<% end -%>
+
+end
+<% end -%>

railties/lib/rails/mailers_controller.rb

@@ -0,0 +1,73 @@
+require 'rails/application_controller'
+
+class Rails::MailersController < Rails::ApplicationController # :nodoc:
+  prepend_view_path ActionDispatch::DebugExceptions::RESCUES_TEMPLATE_PATH
+
+  before_filter :require_local!
+  before_filter :find_preview, only: :preview
+
+  def index
+    @previews = ActionMailer::Preview.all
+    @page_title = "Mailer Previews"
+  end
+
+  def preview
+    if params[:path] == @preview.preview_name
+      @page_title = "Mailer Previews for #{@preview.preview_name}"
+      render action: 'mailer'
+    else
+      email = File.basename(params[:path])
+
+      if @preview.email_exists?(email)
+        @email = @preview.call(email)
+
+        if params[:part]
+          part_type = Mime::Type.lookup(params[:part])
+
+          if part = find_part(part_type)
+            response.content_type = part_type
+            render text: part.respond_to?(:decoded) ? part.decoded : part
+          else
+            raise AbstractController::ActionNotFound, "Email part '#{part_type}' not found in #{@preview.name}##{email}"
+          end
+        else
+          @part = find_preferred_part(request.format, Mime::HTML, Mime::TEXT)
+          render action: 'email', layout: false, formats: %w[html]
+        end
+      else
+        raise AbstractController::ActionNotFound, "Email '#{email}' not found in #{@preview.name}"
+      end
+    end
+  end
+
+  protected
+    def find_preview
+      candidates = []
+      params[:path].to_s.scan(%r{/|$}){ candidates << $` }
+      preview = candidates.detect{ |candidate| ActionMailer::Preview.exists?(candidate) }
+
+      if preview
+        @preview = ActionMailer::Preview.find(preview)
+      else
+        raise AbstractController::ActionNotFound, "Mailer preview '#{params[:path]}' not found"
+      end
+    end
+
+    def find_preferred_part(*formats)
+      if @email.multipart?
+        formats.each do |format|
+          return find_part(format) if @email.parts.any?{ |p| p.mime_type == format }
+        end
+      else
+        @email
+      end
+    end
+
+    def find_part(format)
+      if @email.multipart?
+        @email.parts.find{ |p| p.mime_type == format }
+      elsif @email.mime_type == format
+        @email
+      end
+    end
+end

railties/lib/rails/templates/layouts/application.html.erb

@@ -29,7 +29,12 @@
   </style>
 </head>
 <body>
-<h2>Your App: <%= link_to 'properties', '/rails/info/properties' %> | <%= link_to 'routes', '/rails/info/routes' %></h2>
+<h2>
+  Your App:
+  <%= link_to 'mailers', '/rails/mailers' %> |
+  <%= link_to 'properties', '/rails/info/properties' %> |
+  <%= link_to 'routes', '/rails/info/routes' %>
+</h2>
 <%= yield %>
 
 </body>

railties/lib/rails/templates/rails/mailers/email.html.erb

@@ -0,0 +1,98 @@
+<!DOCTYPE html>
+<html><head>
+<meta name="viewport" content="width=device-width" />
+<style type="text/css">
+  header {
+    width: 100%;
+    padding: 10px 0 0 0;
+    margin: 0;
+    background: white;
+    font: 12px "Lucida Grande", sans-serif;
+    border-bottom: 1px solid #dedede;
+    overflow: hidden;
+  }
+
+  dl {
+    margin: 0 0 10px 0;
+    padding: 0;
+  }
+
+  dt {
+    width: 80px;
+    padding: 1px;
+    float: left;
+    clear: left;
+    text-align: right;
+    color: #7f7f7f;
+  }
+
+  dd {
+    margin-left: 90px; /* 80px + 10px */
+    padding: 1px;
+  }
+
+  iframe {
+    border: 0;
+    width: 100%;
+    height: 800px;
+  }
+</style>
+</head>
+
+<body>
+<header>
+  <dl>
+    <% if @email.respond_to?(:smtp_envelope_from) && Array(@email.from) != Array(@email.smtp_envelope_from) %>
+      <dt>SMTP-From:</dt>
+      <dd><%= @email.smtp_envelope_from %></dd>
+    <% end %>
+
+    <% if @email.respond_to?(:smtp_envelope_to) && @email.to != @email.smtp_envelope_to %>
+      <dt>SMTP-To:</dt>
+      <dd><%= @email.smtp_envelope_to %></dd>
+    <% end %>
+
+    <dt>From:</dt>
+    <dd><%= @email.header['from'] %></dd>
+
+    <% if @email.reply_to %>
+      <dt>Reply-To:</dt>
+      <dd><%= @email.header['reply-to'] %></dd>
+    <% end %>
+
+    <dt>To:</dt>
+    <dd><%= @email.header['to'] %></dd>
+
+    <% if @email.cc %>
+      <dt>CC:</dt>
+      <dd><%= @email.header['cc'] %></dd>
+    <% end %>
+
+    <dt>Date:</dt>
+    <dd><%= Time.current.rfc2822 %></dd>
+
+    <dt>Subject:</dt>
+    <dd><strong><%= @email.subject %></strong></dd>
+
+    <% unless @email.attachments.nil? || @email.attachments.empty? %>
+      <dt>Attachments:</dt>
+      <dd>
+        <%= @email.attachments.map { |a| a.respond_to?(:original_filename) ? a.original_filename : a.filename }.inspect %>
+      </dd>
+    <% end %>
+
+    <% if @email.multipart? %>
+      <dd>
+        <select onchange="document.getElementsByName('messageBody')[0].src=this.options[this.selectedIndex].value;">
+          <option <%= request.format == Mime::HTML ? 'selected' : '' %> value="?part=text%2Fhtml">View as HTML email</option>
+          <option <%= request.format == Mime::TEXT ? 'selected' : '' %> value="?part=text%2Fplain">View as plain-text email</option>
+        </select>
+      </dd>
+    <% end %>
+  </dl>
+</header>
+
+<iframe seamless name="messageBody" src="?part=<%= Rack::Utils.escape(@part.mime_type) %>"></iframe>
+
+</body>
+</html>

railties/lib/rails/templates/rails/mailers/index.html.erb

@@ -0,0 +1,8 @@
+<% @previews.each do |preview| %>
+<h3><%= link_to preview.preview_name.titleize, "/rails/mailers/#{preview.preview_name}" %></h3>
+<ul>
+<% preview.emails.each do |email| %>
+<li><%= link_to email, "/rails/mailers/#{preview.preview_name}/#{email}" %></li>
+<% end %>
+</ul>
+<% end %>

railties/lib/rails/templates/rails/mailers/mailer.html.erb

@@ -0,0 +1,6 @@
+<h3><%= @preview.preview_name.titleize %></h3>
+<ul>
+<% @preview.emails.each do |email| %>
+<li><%= link_to email, "/rails/mailers/#{@preview.preview_name}/#{email}" %></li>
+<% end %>
+</ul>