Table of Contents
This is the first part of a two-series tutorial to setup action mailbox with postfix. In this part, we will implement an action mailbox with postfix and test in development.
If you are only looking to configure postfix in the production server to pipe emails, you can read the second part here.
Rails 6, released with many awesome features and action mailbox, is one of the frameworks that has come to make our life easier. From the Official Action Mailbox Guide:
Action Mailbox routes incoming emails to controller-like mailboxes for processing in Rails. It ships with ingresses for Mailgun, Mandrill, Postmark, and SendGrid. You can also handle inbound mails directly via the built-in Exim, Postfix, and Qmail ingresses.
So basically, an action mailbox can be used to forward all incoming emails to your rails app and process it further as required like storing attachments, creating records from the email body in your DB, and many more.
Skills Required To Follow The Tutorial
- Linux skills to work with commands in the server where your app has been deployed.
- Setup Action Mailbox with relay option for Postfix
- Receive incoming emails through a relay (Postfix)
- Pipe Postfix to forward all incoming emails to our shell script
- Process Email in the mailbox as required
Resources Already Available
- Tutorial to implement and test action mailbox in development.
- Some questions in Stack Overflow but without required answers for our implementation! Frustrating!
You Should Have
- An existing app built with rails 6
First of all, we will setup action mailbox and test in our local machine.
Step 1: Setup Action Mailbox
- Install migrations needed for InboundEmail and ensure Active Storage is set up:
$ rails action_mailbox:install $ rails db:migrate
Step 2: Ingress Configuration
We will be configuring Postfix among various available options.
- Tell Action Mailbox to accept emails from an SMTP relay:
# config/environments/production.rb config.action_mailbox.ingress = :relay
Step 3: Generate Password For Authenticating Requests
You should generate a strong password that Action Mailbox can use to authenticate requests to the relay ingress.
Use rails credentials:edit to add the password to your application’s encrypted credentials under action_mailbox.ingress_password, where Action Mailbox will automatically find it:
action_mailbox: ingress_password: YOUR_STRONG_PASSWORD
If you are using nano editor you can edit credentials with following command:
$ EDITOR="nano" rails credentials:edit
Alternatively, you can also provide the password in the
RAILS_INBOUND_EMAIL_PASSWORD environment variable. If you are using
figaro gem it is as easy as:
Step 4: Setup a mailbox
Now we should setup a mailbox that will process all incoming emails as we require.
- Generate new mailbox
$ bin/rails generate mailbox forwards
This will create
# app/mailboxes/forwards_mailbox.rb class ForwardsMailbox < ApplicationMailbox def process end end
Step 5: Whitelist email domains
We can configure our
application_mailbox to accept all incoming emails to our rails app and forward it to our
forwards_mailbox for further processing. But Action Mailbox also accepts regex to whitelist domains or match certain emails.
- Accept all incoming emails
# app/mailboxes/application_mailbox.rb class ApplicationMailbox < ActionMailbox::Base routing :all => :forwards end
- Accept single email domain
# app/mailboxes/application_mailbox.rb class ApplicationMailbox < ActionMailbox::Base routing /.*@email-domain.com/i => :forwards end
- Accept multiple email domains
# app/mailboxes/application_mailbox.rb class ApplicationMailbox < ActionMailbox::Base routing /.*@firstname.lastname@example.org/i => :forwards end
This regex matching is telling application mailbox to forward or route all emails coming from
@email-domain.com to our
forwards_mailbox. For e.g. if we configure it to be
/.*@gmail.com/i and our rails app receives email to
email@example.com, since this email matches with the pattern
@gmail.com, it will be forwarded to our
forwards_mailbox where we can further process it.
Note: Your mailbox name should match the name you’ve given it in the routing params i.e.
forwards will route to
Step 6: Test in development
For testing in development, Action Mailbox provides UI to test inbound emails in the development environment. To access this, fire up the Rails server first
$ rails s
Now go to
http://localhost:3000/rails/conductor/action_mailbox/inbound_emails and click on
Deliver new inbound email. Fill in all the then click
Deliver inbound email. Ohh wait! before that let’s add
byebug to our
process method so we know action mailbox is actually forwarding our emails to the right place.
# app/mailboxes/forwards_mailbox.rb class ForwardsMailbox < ApplicationMailbox def process byebug end end
You should make sure that email in from input box matches the email domain configured. Now when you click
Deliver inbound email, the execution of the server process should stop at the
process method since we have a breakpoint at there. This means action mailbox is correctly forwarding incoming emails and our configurations are correct. You can perform further process as required in your app now.
That’s it, we have now successfully setup action mailbox and tested in development it is working.
In the second part, we will configure postfix in production server to pipe emails to our rails app where action mailbox will further process it. You can read it here.
If you have any confusions or suggestions, please let me know in comment section below.
References: Action Mailbox