Added cleaner API for delaying mailers in Rails 3

Example:
	UserMailer.delay.signup(@user)

This will enqueue a job that creates the email and calls #deliver on it.

lib/delayed/message_sending.rb

@@ -3,22 +3,23 @@
 
 module Delayed
   class DelayProxy < ActiveSupport::BasicObject
-    def initialize(target, options)
+    def initialize(payload_class, target, options)
+      @payload_class = payload_class
       @target = target
       @options = options
     end
 
     def method_missing(method, *args)
       Job.create({
-        :payload_object => PerformableMethod.new(@target, method.to_sym, args),
+        :payload_object => @payload_class.new(@target, method.to_sym, args),
         :priority       => ::Delayed::Worker.default_priority
       }.merge(@options))
     end
   end
 
   module MessageSending
     def delay(options = {})
-      DelayProxy.new(self, options)
+      DelayProxy.new(PerformableMethod, self, options)
     end
     alias __delay__ delay
 

lib/delayed/performable_mailer.rb

@@ -0,0 +1,21 @@
+require 'action_mailer'
+
+module Delayed
+  class PerformableMailer < PerformableMethod
+    def perform
+      object.send(method, *args).deliver
+    end
+  end
+end
+
+ActionMailer::Base.class_eval do
+  def self.delay(options = {})
+    Delayed::DelayProxy.new(Delayed::PerformableMailer, self, options)
+  end
+end
+
+Mail::Message.class_eval do
+  def delay(*args)
+    raise RuntimeError, "Use MyMailer.delay.mailer_action(args) to delay sending of emails."
+  end
+end

lib/delayed_job.rb

@@ -2,6 +2,7 @@
 
 require File.dirname(__FILE__) + '/delayed/message_sending'
 require File.dirname(__FILE__) + '/delayed/performable_method'
+require File.dirname(__FILE__) + '/delayed/performable_mailer'
 require File.dirname(__FILE__) + '/delayed/yaml_ext'
 require File.dirname(__FILE__) + '/delayed/backend/base'
 require File.dirname(__FILE__) + '/delayed/worker'

spec/performable_mailer_spec.rb

@@ -0,0 +1,46 @@
+require 'spec_helper'
+
+require 'action_mailer'
+class MyMailer < ActionMailer::Base
+  def signup(email)
+    mail :to => email, :subject => "Delaying Emails"
+  end
+end
+
+describe ActionMailer::Base do
+  describe "delay" do
+    it "should enqueue a PerformableEmail job" do
+      lambda {
+        job = MyMailer.delay.signup('john@example.com')
+        job.payload_object.class.should   == Delayed::PerformableMailer
+        job.payload_object.method.should  == :signup
+        job.payload_object.args.should    == ['john@example.com']
+      }.should change { Delayed::Job.count }.by(1)
+    end
+  end
+
+  describe "delay on a mail object" do
+    it "should raise an exception" do
+      lambda {
+        MyMailer.signup('john@example.com').delay
+      }.should raise_error(RuntimeError)
+    end
+  end
+
+  describe Delayed::PerformableMailer do
+    describe "perform" do
+      before do
+        @email = mock('email', :deliver => true)
+        @mailer_class = mock('MailerClass', :signup => @email)
+        @mailer = Delayed::PerformableMailer.new(@mailer_class, :signup, ['john@example.com'])
+      end
+
+      it "should call the method and #deliver on the mailer" do
+        @mailer_class.should_receive(:signup).with('john@example.com')
+        @email.should_receive(:deliver)
+        @mailer.perform
+      end
+    end
+  end
+
+end