cph / ep_postmaster

Engine you can mount and it'll handle postbacks from Mailgun like when an email bounces

EP Postmaster

A drop in solution for handling bounced emails from Mailgun

Usage: In your gemfile

gem ep_postmaster, github: "/cph/ep_postmaster", branch: "master"

and mount it in routes.rb

mount EpPostmaster::Engine => "/api/postmaster"

Setup

You'll need to add the api_key from mailgun along with the default address to send emails from. To do that, create a file in /config/initializers (ep_postmaster.rb in our case).

EpPostmaster.configure do |config|
  config.mailgun_api_key = "MAILGUN_API_KEY"
  config.mailer_sender = "[email protected]"
end

Overriding Default Mail Views

To override the mailer view, just create a file at /views/ep_postmaster/postmaster/bounced_email.txt.erb

You'll have access to the following instance variables.

• @to (The recipient of the bounced email notification)
• @recipient (The original recipient of the bounced email)
• @original_subject (The original subject of the bounced email)
• @error (The error code)

Additional options when a Bounced Email comes in

In your /config/initializers/ep_postmaster.rb file, you can specify an object or class that will handle the bounced email notice after the notification has been sent. To do that, set the bounced_email_handler param:

EpPostmaster.configure do |config|
  config.mailgun_api_key = "MAILGUN_API_KEY"
  config.mailer_sender = "[email protected]"
  config.bounced_email_handler = EmailAddress
end

Then, on the EmailAddress class, define a class level method called handle_bounced_email!. This method should accept two arguments: the recipient that bounced back, and the MailgunPost object with all params sent back from Mailgun.

Example:

class EmailAddress
...
  def self.handle_bounced_email!(email, mailgun_post)
    find_by(address: email).update_attribute(:undeliverable, true)
  end
...
end