has_emails

has_emails demonstrates a reference implementation for sending emails with logging and asynchronous support.

Resources

API

• api.pluginaweek.org/has_emails

Bugs

• pluginaweek.lighthouseapp.com/projects/13272-has_emails

Development

• github.com/pluginaweek/has_emails

Source

• git://github.com/pluginaweek/has_emails.git

Description

Emailing between users and other parts of a system is a fairly common feature in web applications, especially for those that support social networking. Emailing doesn’t necessarily need to be between users, but can also act as a way for the web application to send notices and other notifications to users.

Rails already provides ActionMailer as a way of sending emails. However, the framework does not provide an easy way to persist emails, track their status, and process them asynchronously. Designing and building a framework that supports this can be complex and takes away from the business focus. This plugin can help ease that process by demonstrating a complete implementation of these features.

Usage

Creating new emails

Emails should usually still be created using ActionMailer. However, instead of delivering the emails, you can queue the emails like so:

  Notifier.deliver_signup_notification(david) # sends the email now
  Notifier.queue_signup_notification(david) # sends the email later (has_emails kicks in)

In addition to queueing emails, you can build them directly like so:

  email_address = EmailAddress.find(123)
  email = email_address.emails.build
  email.to EmailAddress.find(456)
  email.subject = 'Hey!'
  email.body = 'Does anyone want to go out tonight?'
  email.deliver

Replying to emails

  reply = email.reply_to_all
  reply.body = "I'd love to go out!"
  reply.deliver

Forwarding emails

  forward = email.forward
  forward.body = 'Interested?'
  forward.deliver

Processing email asynchronously

In addition to delivering emails immediately, you can also queue emails so that an external application processes and delivers them (as mentioned above). This is especially useful when you want to asynchronously send e-mails so that it doesn’t block the user interface on your web application.

To process queued emails, you need an external cron job that checks and sends them like so:

  Email.with_state('queued').each do |email|
    email.deliver
  end

Testing

Before you can run any tests, the following gem must be installed:

• plugin_test_helper

To run against a specific version of Rails:

  rake test RAILS_FRAMEWORK_ROOT=/path/to/rails

Dependencies

• Rails 2.1 or later
• has_messages
• state_machine
• plugins_plus (optional if app files are copied to your project tree)