has_emails ¶ ↑

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

API

• rdoc.info/github/pluginaweek/has_emails/master/frames

Bugs

• github.com/pluginaweek/has_emails/issues

Development

• github.com/pluginaweek/has_emails

Testing

• travis-ci.org/pluginaweek/has_emails

Source

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

Mailing List

• groups.google.com/group/pluginaweek-talk

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 reference implementation of these features.

has_emails requires an additional database table to work. You can generate a migration for this tables like so:

script/generate has_emails

Then simply migrate your database:

rake db:migrate

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

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

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

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

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

• Rails 2.3 or later

• has_messages

• state_machine