In the last posting, we talked about an ActionMailer active-check. For this approach to work, we need to register all instance-methods of all ActionMailer classes of our rails-app into the database.

The commonly used solution for this task is to search through your app/models directory, require all the *_mailer.rb classes and save them to the database. Like this:

   1  Dir.glob("#{RAILS_ROOT}/app/models/*_mailer.rb").each do |file|
   2    klass = File.basename( file, '.rb').classify.constantize
   3    klass.instance_methods(false).each do |meth|
   4      SystemMailer.find_or_create_by_mailer_class_and_mailer_method(
   5        :mailer_class => klass.to_s,
   6        :mailer_method => meth,
   7        :active => true
   8      )
   9    end
  10  end

Put this into an initializer or your environment.rb file and you'r good to go. The downfall of this solution: You have to know all the directories of your Mailer classes, which might not be a problem, if you're following the "convention-over-configuration" rule inside your rails-app.

Another approach might be to get all subclasses of ActionMailer::Base:

   1  ActionMailer::Base.subclasses_of( ActionMailer::Base ).each do |klass|
   2    klass.instance_methods(false).each do |meth|
   3      SystemMailer.find_or_create_by_mailer_class_and_mailer_method(
   4        :mailer_class => klass.to_s,
   5        :mailer_method => meth,
   6        :active => true
   7      )
   8    end
   9  end

But this only works, if the subclasses of ActionMailer::Base are fully loaded/required (which is not the case, if your server just starts up).