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diff --git a/guides/source/action_mailbox_basics.md b/guides/source/action_mailbox_basics.md new file mode 100644 index 0000000000..eb8a14b4d2 --- /dev/null +++ b/guides/source/action_mailbox_basics.md @@ -0,0 +1,302 @@ +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON https://guides.rubyonrails.org.** + +Action Mailbox Basics +===================== + +This guide provides you with all you need to get started in receiving +emails to your application. + +After reading this guide, you will know: + +* How to receive email within a Rails application. +* How to configure Action Mailbox. +* How to generate and route emails to a mailbox. +* How to test incoming emails. + +-------------------------------------------------------------------------------- + +Introduction +------------ + +Action Mailbox routes incoming emails to controller-like mailboxes for +processing in Rails. It ships with ingresses for Amazon SES, Mailgun, Mandrill, +and SendGrid. You can also handle inbound mails directly via the built-in +Postfix ingress. + +The inbound emails are turned into `InboundEmail` records using Active Record +and feature lifecycle tracking, storage of the original email on cloud storage +via Active Storage, and responsible data handling with +on-by-default incineration. + +These inbound emails are routed asynchronously using Active Job to one or +several dedicated mailboxes, which are capable of interacting directly +with the rest of your domain model. + +## Setup + +Install migrations needed for `InboundEmail` and ensure Active Storage is set up: + +```bash +$ rails action_mailbox:install +$ rails db:migrate +``` + +## Configuration + +### Amazon SES + +Install the [`aws-sdk-sns`](https://rubygems.org/gems/aws-sdk-sns) gem: + +```ruby +# Gemfile +gem "aws-sdk-sns", ">= 1.9.0", require: false +``` + +Tell Action Mailbox to accept emails from SES: + +```ruby +# config/environments/production.rb +config.action_mailbox.ingress = :amazon +``` + +[Configure SES](https://docs.aws.amazon.com/ses/latest/DeveloperGuide/receiving-email-notifications.html) +to deliver emails to your application via POST requests to +`/rails/action_mailbox/amazon/inbound_emails`. If your application lived at +`https://example.com`, you would specify the fully-qualified URL +`https://example.com/rails/action_mailbox/amazon/inbound_emails`. + +### Mailgun + +Give Action Mailbox your +[Mailgun API key](https://help.mailgun.com/hc/en-us/articles/203380100-Where-can-I-find-my-API-key-and-SMTP-credentials) +so it can authenticate requests to the Mailgun ingress. + +Use `rails credentials:edit` to add your API key to your application's +encrypted credentials under `action_mailbox.mailgun_api_key`, +where Action Mailbox will automatically find it: + +```yaml +action_mailbox: + mailgun_api_key: ... +``` + +Alternatively, provide your API key in the `MAILGUN_INGRESS_API_KEY` environment +variable. + +Tell Action Mailbox to accept emails from Mailgun: + +```ruby +# config/environments/production.rb +config.action_mailbox.ingress = :mailgun +``` + +[Configure Mailgun](https://documentation.mailgun.com/en/latest/user_manual.html#receiving-forwarding-and-storing-messages) +to forward inbound emails to `/rails/action_mailbox/mailgun/inbound_emails/mime`. +If your application lived at `https://example.com`, you would specify the +fully-qualified URL `https://example.com/rails/action_mailbox/mailgun/inbound_emails/mime`. + +### Mandrill + +Give Action Mailbox your Mandrill API key so it can authenticate requests to +the Mandrill ingress. + +Use `rails credentials:edit` to add your API key to your application's +encrypted credentials under `action_mailbox.mandrill_api_key`, +where Action Mailbox will automatically find it: + +```yaml +action_mailbox: + mandrill_api_key: ... +``` + +Alternatively, provide your API key in the `MANDRILL_INGRESS_API_KEY` +environment variable. + +Tell Action Mailbox to accept emails from Mandrill: + +```ruby +# config/environments/production.rb +config.action_mailbox.ingress = :mandrill +``` + +[Configure Mandrill](https://mandrill.zendesk.com/hc/en-us/articles/205583197-Inbound-Email-Processing-Overview) +to route inbound emails to `/rails/action_mailbox/mandrill/inbound_emails`. +If your application lived at `https://example.com`, you would specify +the fully-qualified URL `https://example.com/rails/action_mailbox/mandrill/inbound_emails`. + +### Postfix + +Tell Action Mailbox to accept emails from Postfix: + +```ruby +# config/environments/production.rb +config.action_mailbox.ingress = :postfix +``` + +Generate a strong password that Action Mailbox can use to authenticate requests to the Postfix 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: + +```yaml +action_mailbox: + ingress_password: ... +``` + +Alternatively, provide the password in the `RAILS_INBOUND_EMAIL_PASSWORD` environment variable. + +[Configure Postfix](https://serverfault.com/questions/258469/how-to-configure-postfix-to-pipe-all-incoming-email-to-a-script) +to pipe inbound emails to `bin/rails action_mailbox:ingress:postfix`, providing +the `URL` of the Postfix ingress and the `INGRESS_PASSWORD` you previously +generated. If your application lived at `https://example.com`, the full command +would look like this: + +```bash +$ URL=https://example.com/rails/action_mailbox/postfix/inbound_emails INGRESS_PASSWORD=... rails action_mailbox:ingress:postfix +``` + +### SendGrid + +Tell Action Mailbox to accept emails from SendGrid: + +```ruby +# config/environments/production.rb +config.action_mailbox.ingress = :sendgrid +``` + +Generate a strong password that Action Mailbox can use to authenticate +requests to the SendGrid 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: + +```yaml +action_mailbox: + ingress_password: ... +``` + +Alternatively, provide the password in the `RAILS_INBOUND_EMAIL_PASSWORD` +environment variable. + +[Configure SendGrid Inbound Parse](https://sendgrid.com/docs/for-developers/parsing-email/setting-up-the-inbound-parse-webhook/) +to forward inbound emails to +`/rails/action_mailbox/sendgrid/inbound_emails` with the username `actionmailbox` +and the password you previously generated. If your application lived at `https://example.com`, +you would configure SendGrid with the following URL: + +``` +https://actionmailbox:PASSWORD@example.com/rails/action_mailbox/sendgrid/inbound_emails +``` + +NOTE: When configuring your SendGrid Inbound Parse webhook, be sure to check the box labeled **“Post the raw, full MIME message.”** Action Mailbox needs the raw MIME message to work. + +## Examples + +Configure basic routing: + +```ruby +# app/mailboxes/application_mailbox.rb +class ApplicationMailbox < ActionMailbox::Base + routing /^save@/i => :forwards + routing /@replies\./i => :replies +end +``` + +Then set up a mailbox: + +```ruby +# Generate new mailbox +$ bin/rails generate mailbox forwards +``` + +```ruby +# app/mailboxes/forwards_mailbox.rb +class ForwardsMailbox < ApplicationMailbox + # Callbacks specify prerequisites to processing + before_processing :require_forward + + def process + if forwarder.buckets.one? + record_forward + else + stage_forward_and_request_more_details + end + end + + private + def require_forward + unless message.forward? + # Use Action Mailers to bounce incoming emails back to sender – this halts processing + bounce_with Forwards::BounceMailer.missing_forward( + inbound_email, forwarder: forwarder + ) + end + end + + def forwarder + @forwarder ||= Person.where(email_address: mail.from) + end + + def record_forward + forwarder.buckets.first.record \ + Forward.new forwarder: forwarder, subject: message.subject, content: mail.content + end + + def stage_forward_and_request_more_details + Forwards::RoutingMailer.choose_project(mail).deliver_now + end +end +``` + +## Incineration of InboundEmails + +By default, an InboundEmail that has been successfully processed will be +incinerated after 30 days. This ensures you're not holding on to people's data +willy-nilly after they may have canceled their accounts or deleted their +content. The intention is that after you've processed an email, you should have +extracted all the data you needed and turned it into domain models and content +on your side of the application. The InboundEmail simply stays in the system +for the extra time to provide debugging and forensics options. + +The actual incineration is done via the `IncinerationJob` that's scheduled +to run after `config.action_mailbox.incinerate_after` time. This value is +by default set to `30.days`, but you can change it in your production.rb +configuration. (Note that this far-future incineration scheduling relies on +your job queue being able to hold jobs for that long.) + +## Working with Action Mailbox in development + +It's helpful to be able to test incoming emails in development without actually +sending and receiving real emails. To accomplish this, there's a conductor +controller mounted at `/rails/conductor/action_mailbox/inbound_emails`, +which gives you an index of all the InboundEmails in the system, their +state of processing, and a form to create a new InboundEmail as well. + +## Testing mailboxes + +Example: + +```ruby +class ForwardsMailboxTest < ActionMailbox::TestCase + test "directly recording a client forward for a forwarder and forwardee corresponding to one project" do + assert_difference -> { people(:david).buckets.first.recordings.count } do + receive_inbound_email_from_mail \ + to: 'save@example.com', + from: people(:david).email_address, + subject: "Fwd: Status update?", + body: <<~BODY + --- Begin forwarded message --- + From: Frank Holland <frank@microsoft.com> + + What's the status? + BODY + end + + recording = people(:david).buckets.first.recordings.last + assert_equal people(:david), recording.creator + assert_equal "Status update?", recording.forward.subject + assert_match "What's the status?", recording.forward.content.to_s + end +end +``` |