Refactor MJML layout/template support

Gemfile

@@ -2,7 +2,8 @@ source 'https://rubygems.org'
 
 gemspec
 
-gem 'rails', '4.2.6'
+gem 'rails', '~> 5.2'
+gem 'byebug'
 
 group :development do
   # gem 'guard' # NOTE: this is necessary in newer versions

Gemfile.lock

@@ -6,93 +6,104 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    actionmailer (4.2.6)
-      actionpack (= 4.2.6)
-      actionview (= 4.2.6)
-      activejob (= 4.2.6)
+    actioncable (5.2.0)
+      actionpack (= 5.2.0)
+      nio4r (~> 2.0)
+      websocket-driver (>= 0.6.1)
+    actionmailer (5.2.0)
+      actionpack (= 5.2.0)
+      actionview (= 5.2.0)
+      activejob (= 5.2.0)
       mail (~> 2.5, >= 2.5.4)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
-    actionpack (4.2.6)
-      actionview (= 4.2.6)
-      activesupport (= 4.2.6)
-      rack (~> 1.6)
-      rack-test (~> 0.6.2)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      rails-dom-testing (~> 2.0)
+    actionpack (5.2.0)
+      actionview (= 5.2.0)
+      activesupport (= 5.2.0)
+      rack (~> 2.0)
+      rack-test (>= 0.6.3)
+      rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (4.2.6)
-      activesupport (= 4.2.6)
+    actionview (5.2.0)
+      activesupport (= 5.2.0)
       builder (~> 3.1)
-      erubis (~> 2.7.0)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
-      rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    activejob (4.2.6)
-      activesupport (= 4.2.6)
-      globalid (>= 0.3.0)
-    activemodel (4.2.6)
-      activesupport (= 4.2.6)
-      builder (~> 3.1)
-    activerecord (4.2.6)
-      activemodel (= 4.2.6)
-      activesupport (= 4.2.6)
-      arel (~> 6.0)
-    activesupport (4.2.6)
-      i18n (~> 0.7)
-      json (~> 1.7, >= 1.7.7)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.3)
+    activejob (5.2.0)
+      activesupport (= 5.2.0)
+      globalid (>= 0.3.6)
+    activemodel (5.2.0)
+      activesupport (= 5.2.0)
+    activerecord (5.2.0)
+      activemodel (= 5.2.0)
+      activesupport (= 5.2.0)
+      arel (>= 9.0)
+    activestorage (5.2.0)
+      actionpack (= 5.2.0)
+      activerecord (= 5.2.0)
+      marcel (~> 0.3.1)
+    activesupport (5.2.0)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
       minitest (~> 5.1)
-      thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
-    arel (6.0.4)
+    arel (9.0.0)
     builder (3.2.3)
+    byebug (10.0.2)
     concurrent-ruby (1.0.5)
     crass (1.0.4)
-    erubis (2.7.0)
+    erubi (1.7.1)
     globalid (0.4.1)
       activesupport (>= 4.2.0)
-    i18n (0.9.5)
+    i18n (1.0.1)
       concurrent-ruby (~> 1.0)
-    json (1.8.6)
     loofah (2.2.2)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.0)
       mini_mime (>= 0.1.1)
+    marcel (0.3.2)
+      mimemagic (~> 0.3.2)
     metaclass (0.0.4)
+    method_source (0.9.0)
+    mimemagic (0.3.2)
     mini_mime (1.0.0)
     mini_portile2 (2.3.0)
     minitest (5.11.3)
     mocha (1.4.0)
       metaclass (~> 0.0.1)
-    nokogiri (1.8.2)
+    nio4r (2.3.1)
+    nokogiri (1.8.4)
       mini_portile2 (~> 2.3.0)
-    rack (1.6.10)
-    rack-test (0.6.3)
-      rack (>= 1.0)
-    rails (4.2.6)
-      actionmailer (= 4.2.6)
-      actionpack (= 4.2.6)
-      actionview (= 4.2.6)
-      activejob (= 4.2.6)
-      activemodel (= 4.2.6)
-      activerecord (= 4.2.6)
-      activesupport (= 4.2.6)
-      bundler (>= 1.3.0, < 2.0)
-      railties (= 4.2.6)
-      sprockets-rails
-    rails-deprecated_sanitizer (1.0.3)
-      activesupport (>= 4.2.0.alpha)
-    rails-dom-testing (1.0.9)
-      activesupport (>= 4.2.0, < 5.0)
-      nokogiri (~> 1.6)
-      rails-deprecated_sanitizer (>= 1.0.1)
+    rack (2.0.5)
+    rack-test (1.0.0)
+      rack (>= 1.0, < 3)
+    rails (5.2.0)
+      actioncable (= 5.2.0)
+      actionmailer (= 5.2.0)
+      actionpack (= 5.2.0)
+      actionview (= 5.2.0)
+      activejob (= 5.2.0)
+      activemodel (= 5.2.0)
+      activerecord (= 5.2.0)
+      activestorage (= 5.2.0)
+      activesupport (= 5.2.0)
+      bundler (>= 1.3.0)
+      railties (= 5.2.0)
+      sprockets-rails (>= 2.0.0)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
     rails-html-sanitizer (1.0.4)
       loofah (~> 2.2, >= 2.2.2)
-    railties (4.2.6)
-      actionpack (= 4.2.6)
-      activesupport (= 4.2.6)
+    railties (5.2.0)
+      actionpack (= 5.2.0)
+      activesupport (= 5.2.0)
+      method_source
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rake (12.3.1)
-    sprockets (3.7.1)
+    sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-rails (3.2.1)
@@ -103,14 +114,18 @@ GEM
     thread_safe (0.3.6)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
+    websocket-driver (0.7.0)
+      websocket-extensions (>= 0.1.0)
+    websocket-extensions (0.1.3)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
+  byebug
   mjml-rails!
   mocha (= 1.4.0)
-  rails (= 4.2.6)
+  rails (~> 5.2)
 
 BUNDLED WITH
-   1.16.1
+   1.16.2

README.md

@@ -7,7 +7,7 @@
 An example template might look like:
 
 ```erb
-<!-- ./app/views/user_mailer/email.mjml -->
+<!-- ./app/views/user_mailer/email.html.mjml -->
 <mjml>
   <mj-head>
     <mj-preview>Hello World</mj-preview>
@@ -16,7 +16,7 @@ An example template might look like:
     <mj-section>
       <mj-column>
         <mj-text>Hello World</mj-text>
-        <%= render :partial => 'info', :formats => [:html] %>
+        <%= render partial: "info" %>
       </mj-column>
     </mj-section>
   </mj-body>
@@ -26,19 +26,19 @@ An example template might look like:
 And the partial `_info.mjml`:
 
 ```erb
-<!-- ./app/views/user_mailer/_info.mjml -->
+<!-- ./app/views/user_mailer/_info.html.erb -->
 <mj-text>This is <%= @user.username %></mj-text>
 ```
 
-* Notice you can use ERb and partials inside the template.
+* Notice you can use ERB and partials inside the template.
 
 Your `user_mailer.rb` might look like this::
 
 ```ruby
 # ./app/mailers/user_mailer.rb
 class UserMailer < ActionMailer::Base
-  def user_signup_confirmation()
-    mail(to: 'test@example.com', subject: 'test') do |format|
+  def user_signup_confirmation
+    mail(to: "user@example.com", from: "app@example.com") do |format|
       format.text
       format.mjml
     end
@@ -118,65 +118,53 @@ npm install -g mjml@3.3.5
 
 Mailer:
 ```ruby
-# mailers/foo_mailer.rb
+# mailers/my_mailer.rb
 class MyMailer < ActionMailer::Base
   layout "default"
 
-  def mail_template(template_name, recipient, subject, **params)
-    mail(
-      to: recipient.email,
-      from: ENV["MAILER_FROM"],
-      subject: subject
-    ) do |format|
-      format.mjml { render template_name, locals: { recipient: recipient }.merge(params) }
-    end
-  end
+  def foo_bar(user)
+    @recipient = user
 
-  # this function is called to send the email
-  def foo(item, user)
-    mail_template(
-      "foo_bar",
-      user,
-      "email subject",
-      request: item
-    )
+    mail(to: user.email, from: "app@example.com") do |format|
+      format.html
+    end
   end
 end
 ```
 
 Email layout:
 ```html
-<!-- views/layouts/default.mjml -->
+<!-- views/layouts/default.html.mjml -->
 <mjml>
-	<mj-body>
-		<%= yield %>
-	</mj-body>
+  <mj-body>
+    <%= yield %>
+  </mj-body>
 </mjml>
 ```
 
 Email view:
 ```html
-<!-- views/my_mailer/foo_bar.mjml.erb -->
-<%= render partial: "to", formats: [:html], locals: { name: recipient.name } %>
+<!-- views/my_mailer/foo_bar.html.erb -->
+<%= render partial: "to" %>
 
 <mj-section>
-	<mj-column>
-		<mj-text>
-			Hello <%= recipient.name %>!
-		</mj-text>
-	</mj-column>
+  <mj-column>
+    <mj-text>
+      Something foo regarding bar!
+    </mj-text>
+  </mj-column>
 </mj-section>
 ```
 
 Email partial:
 ```html
-<!-- views/my_mailer/_to.mjml -->
+<!-- views/my_mailer/_to.html.erb -->
 <mj-section>
-	<mj-column>
-		<mj-text>
-			<%= name %>,
-		</mj-text>
-	</mj-column>
+  <mj-column>
+    <mj-text>
+      Hello <%= @recipient.name %>,
+    </mj-text>
+  </mj-column>
 </mj-section>
 ```
 

lib/generators/mjml/mailer/mailer_generator.rb

@@ -5,10 +5,10 @@ module Generators
     class MailerGenerator < Erb::Generators::MailerGenerator
       source_root File.expand_path("../templates", __FILE__)
 
-      protected
+      private
 
       def format
-        nil # Our templates have no format
+        :html
       end
 
       def formats
@@ -18,6 +18,17 @@ def formats
       def handler
         :mjml
       end
+
+      def view_handler
+        Mjml.template_language
+      end
+
+      def filename_with_extensions(name, file_format = format)
+        # Due to MJML single-pass processing nature
+        # layout files MUST have .mjml extension, but views/templates cannot
+        is_layout_file = name.in?([:layout, "mailer"])
+        [name, file_format, is_layout_file ? handler : view_handler].compact.join(".")
+      end
     end
   end
 end

lib/generators/mjml/mailer/templates/layout.html.mjml

@@ -0,0 +1,5 @@
+<mjml>
+  <mj-body>
+    <%%= yield %>
+  </mj-body>
+</mjml>

lib/mjml.rb

@@ -41,7 +41,15 @@ def template_handler
 
     def call(template)
       compiled_source = template_handler.call(template)
-      if template.formats.include?(:mjml)
+
+      # Per MJML v4 syntax documentation[0] valid/render'able document MUST start with <mjml> root tag
+      # If we get here and template source doesn't start with one it means
+      # that we are rendering partial named according to legacy naming convention (partials ending with '.mjml')
+      # Therefore we skip MJML processing and return raw compiled source. It will be processed
+      # by MJML library when top-level layout/template is rendered
+      #
+      # [0] - https://github.com/mjmlio/mjml/blob/master/doc/guide.md#mjml
+      if template.source =~ /<mjml>/
         "Mjml::Mjmltemplate.to_html(begin;#{compiled_source};end).html_safe"
       else
         compiled_source