Asynchronously send mail using ActionMailer and Que.

So far, this has been tested only in Rails 4.

Que is an alternative DelayedJob or QueueClassic and is a queue for Ruby. It uses PostgreSQL's [advisory locks] (http://www.postgresql.org/docs/current/static/explicit-locking.html#ADVISORY-LOCKS) to manage jobs. See the que repo for more details.

• Que-Mailer uses Postgres rather than Redis, RabbitMQ or other message queue. If you already have Postgres on a project, now you have 1 fewer dependency!
• Que-Mailer can create background workers within your existing process. This means, for instance, that your background workers and web server can share a Heroku dyno. It also means that you don't have to remember to launch separate workers.
• All of the benefits of using advisory locks and Postgres (like safety, security, and atomic backups.)

Que and Que-Mailer are fairly new compared to other queue solutions. We're still finding bugs and have only tested in a limited set of configurations.

If you have problems, please post an issue.

Right now it is best to use the github master version.

Add this line to your application's Gemfile:

gem 'que_mailer', :git => 'git://github.com/prehnRA/que-mailer.git', :branch => 'master'

And then execute:

$ bundle

Additionally, you need to follow the steps for installing and using Que. Remember to:

$ rails generate que:install
$ rake db:migrate

Which will get your database ready to store jobs.

You use Que-Mailer by including it in your mailers, like this:

class ExampleMailer < ActionMailer::Base
  include Que::Mailer
  default from: '[email protected]'
  
  def example_message(*args)
    @args = *args
    mail(to: "[email protected]", subject: "Hello World")
  end
end

Then,

ExampleMailer.example_message.deliver 

will send mail using the background workers.

ExampleMailer.example_message.deliver!

will bypass Que and send the mail directly.

Additionally, you can schedule mail to be sent at a later time.

ExampleMailer.deliver_in(2.days)

will send an email two days from now.

ExampleMailer.deliver_at(time)

will deliver the email at time.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

You can also help by testing this in your application and reporting any issues you encounter.

MIT