Ability to use an yml file with separate smtp settings for ar_sendmail

lib/action_mailer/ar_mailer.rb

@@ -17,6 +17,19 @@ def self.email_class=(klass)
   def self.email_class
     @@email_class_name.constantize
   end
+
+  ##
+  # Set the name of the yml config file for smtp.
+  #
+  @@smtp_settings_path_name = "#{Rails.root}/config/smtp_settings.yml"
+
+  def self.smtp_settings_path=(filename)
+    @@smtp_settings_path_name = filename
+  end
+
+  def self.smtp_settings_path
+    @@smtp_settings_path_name
+  end
 
   ##
   # Adds +mail+ to the Email table.  Only the first From address for +mail+ is

lib/action_mailer/ar_sendmail.rb

@@ -370,7 +370,7 @@ def deliver(emails)
     else
       settings << smtp_settings[:tls]
     end
-
+    
     smtp.start(*settings) do |session|
       @failed_auth_count = 0
       until emails.empty? do
@@ -468,15 +468,25 @@ def run
   end
 
   ##
-  # Proxy to ActionMailer::Base::smtp_settings.  See
+  # Either settings loaded from smtp settings file or 
+  # proxy to ActionMailer::Base::smtp_settings. See
   # http://api.rubyonrails.org/classes/ActionMailer/Base.html
   # for instructions on how to configure ActionMailer's SMTP server.
   #
   # Falls back to ::server_settings if ::smtp_settings doesn't exist for
   # backwards compatibility.
 
   def smtp_settings
-    ActionMailer::Base.smtp_settings rescue ActionMailer::Base.server_settings
+    @smtp_settings ||= begin
+      if File.exists?(ActionMailer::Base.smtp_settings_path)
+        config = YAML::load_file(ActionMailer::Base.smtp_settings_path)
+        config = (config.has_key?(Rails.env) ? config[Rails.env] : config).with_indifferent_access
+        config[:authentication] = config[:authentication].to_sym if config[:authentication]
+        config
+      else
+        ActionMailer::Base.smtp_settings rescue ActionMailer::Base.server_settings
+      end
+    end
   end
 
 end