handle asset_host

README.md

@@ -256,18 +256,13 @@ end
 
 ## Known issues ##
 
-Roadie will not be able to find your stylesheets if you have an `asset_host` configured and will ignore those lines when inlining.
-
-A workaround for this is to not use `asset_host` in your mailers:
+If you need to set an `asset_host` in your mailer, it must be done before `Roadie::Rails::Automatic` is `include`d. For example:
 
 ```ruby
-config.action_controller.asset_host = # ...
-config.action_mailer.asset_host = nil
-
-# or
-
 class MyMailer < ActionMailer::Base
-  self.asset_host = nil
+  self.asset_host = 'http://mail-cdn.mysite.com'
+
+  include Roadie::Rails::Automatic
 end
 ```
 

lib/roadie/rails.rb

@@ -3,6 +3,8 @@ module Rails
   end
 end
 
+require "active_support/concern"
+
 require "roadie"
 
 require "roadie/rails/version"
@@ -12,6 +14,7 @@ module Rails
 require "roadie/rails/mail_inliner"
 
 require "roadie/rails/asset_pipeline_provider"
+require "roadie/rails/css_localizer"
 
 require "roadie/rails/mailer"
 

lib/roadie/rails/automatic.rb

@@ -1,6 +1,12 @@
 module Roadie
   module Rails
     module Automatic
+      extend ActiveSupport::Concern
+
+      included do
+        include CssLocalizer
+      end
+
       def mail(*args, &block)
         super.tap do |email|
           email.extend InlineOnDelivery

lib/roadie/rails/css_localizer.rb

@@ -0,0 +1,36 @@
+module Roadie
+  module Rails
+    module CssLocalizer
+      extend ActiveSupport::Concern
+
+      included do
+        old_asset_host = self.asset_host
+        if old_asset_host
+          # don't include an asset_host for CSS files, so that they are picked up by Roadie
+          self.asset_host = Proc.new { |source, request|
+            uri = URI::parse(source)
+            if uri.path.end_with?('.css')
+              nil
+            else
+              # logic copied from Rails
+              # http://git.io/vhYx7Q
+              if old_asset_host.respond_to?(:call)
+                # the original asset_host was a Proc
+                arity = old_asset_host.respond_to?(:arity) ? old_asset_host.arity : old_asset_host.method(:call).arity
+                args = [source]
+                args << request if request && (arity > 1 || arity < 0)
+                old_asset_host.call(*args)
+              elsif old_asset_host =~ /%d/
+                # the original asset_host was a string value that needs the filename checksum added
+                old_asset_host % (Zlib.crc32(source) % 4)
+              else
+                # the original asset_host was a simple string value
+                old_asset_host
+              end
+            end
+          }
+        end
+      end
+    end
+  end
+end

lib/roadie/rails/mailer.rb

@@ -1,6 +1,12 @@
 module Roadie
   module Rails
     module Mailer
+      extend ActiveSupport::Concern
+
+      included do
+        include CssLocalizer
+      end
+
       def roadie_mail(options = {}, &block)
         email = mail(options, &block)
         MailInliner.new(email, roadie_options).execute

spec/integration_spec.rb

@@ -76,6 +76,29 @@ def parse_html_in_email(mail)
         email.deliver
       end
 
+      it "sets the proper host for images with automatic mailer" do
+        email = app.read_delivered_email(:asset_email)
+
+        html = email.html_part.body.decoded
+        expect(html).to include '<!DOCTYPE'
+        expect(html).to include '<head'
+        expect(html).to_not include '<link'
+
+        document = parse_html_in_email(email)
+        expect(document).to have_selector('body img')
+
+        if app.using_asset_pipeline?
+          expected_image_url = 'http://asset.host.com/assets/rails.png'
+        else
+          expected_image_url = 'http://asset.host.com/images/rails.png'
+        end
+        expect(document).to have_selector("img[src=\"#{expected_image_url}\"]")
+
+        # If we deliver mails we can catch weird problems with headers being invalid
+        email.delivery_method :test
+        email.deliver
+      end
+
       it "inlines no styles when roadie_options are nil" do
         email = app.read_delivered_email(:disabled_email)
 

spec/lib/roadie/rails/automatic_spec.rb

@@ -5,6 +5,8 @@ module Roadie
   module Rails
     describe Automatic do
       base_mailer = Class.new do
+        cattr_accessor :asset_host
+
         def initialize(email = nil)
           @email = email
         end

spec/lib/roadie/rails/css_localizer_spec.rb

@@ -0,0 +1,39 @@
+require 'spec_helper'
+
+module Roadie
+  module Rails
+    describe CssLocalizer do
+      base_mailer = Class.new do
+        cattr_accessor :asset_host
+      end
+
+      describe "#asset_host" do
+        it "passes all arguments to the underlying simple accessor" do
+          string_host_mailer = Class.new(base_mailer) do
+            self.asset_host = 'http://original.com'
+
+            include CssLocalizer
+          end
+
+          asset_host = string_host_mailer.asset_host
+          expect(asset_host).to be_a(Proc)
+          expect(asset_host.call('foo.png')).to eq('http://original.com')
+        end
+
+        it "passes all arguments to the underlying proc accessor" do
+          proc_host_mailer = Class.new(base_mailer) do
+            self.asset_host = Proc.new { |source, request|
+              'http://original.com'
+            }
+
+            include CssLocalizer
+          end
+
+          asset_host = proc_host_mailer.asset_host
+          expect(asset_host).to be_a(Proc)
+          expect(asset_host.call('foo.png')).to eq('http://original.com')
+        end
+      end
+    end
+  end
+end

spec/lib/roadie/rails/mailer_spec.rb

@@ -5,6 +5,8 @@ module Roadie
   module Rails
     describe Mailer do
       some_mailer = Class.new do
+        cattr_accessor :asset_host
+
         include Mailer
 
         def initialize(email = nil)

spec/railsapps/shared/all/app/mailers/auto_mailer.rb

@@ -1,4 +1,6 @@
 class AutoMailer < ActionMailer::Base
+  self.asset_host = 'http://asset.host.com'
+
   include Roadie::Rails::Automatic
 
   default from: 'john@example.com'
@@ -7,6 +9,10 @@ def normal_email
     generate_email
   end
 
+  def asset_email
+    mail(to: 'example@example.org', subject: "Notification for you")
+  end
+
   def disabled_email
     generate_email
   end

spec/railsapps/shared/all/app/mailers/mailer.rb

@@ -1,4 +1,6 @@
 class Mailer < ActionMailer::Base
+  self.asset_host = 'http://asset.host.com'
+
   include Roadie::Rails::Mailer
 
   default from: 'john@example.com'

spec/railsapps/shared/all/app/views/mailer/asset_email.html.erb

@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta http-equiv="content-type" content="text/html; charset=utf-8">
+    <%= stylesheet_link_tag "email" %>
+  </head>
+  <body>
+    <h1>Normal email</h1>
+    <%= image_tag "rails.png" %>
+  </body>
+</html>

spec/railsapps/shared/all/app/views/mailer/asset_email.text

@@ -0,0 +1 @@
+Asset email