class ActionMailbox::Ingresses::Mailgun::InboundEmailsController

https://example.com/rails/action_mailbox/mailgun/inbound_emails/mime.
If your application lived at https://example.com, you would specify the fully-qualified URL
to forward inbound emails to /rails/action_mailbox/mailgun/inbound_emails/mime.
3. {Configure Mailgun}[https://documentation.mailgun.com/en/latest/user_manual.html#receiving-forwarding-and-storing-messages]

config.action_mailbox.ingress = :mailgun
# config/environments/production.rb
2. Tell Action Mailbox to accept emails from Mailgun:
Alternatively, provide your Signing key in the MAILGUN_INGRESS_SIGNING_KEY environment variable.
mailgun_signing_key: …
action_mailbox:
action_mailbox.mailgun_signing_key, where Action Mailbox will automatically find it:
Use bin/rails credentials:edit to add your Signing key to your application’s encrypted credentials under
so it can authenticate requests to the Mailgun ingress.
1. Give Action Mailbox your Mailgun Signing key (which you can find under Settings -> Security & Users -> API security in Mailgun)
== Usage
the Active Storage service, or the Active Job backend is misconfigured or unavailable
- 500 Server Error if the Mailgun Signing key is missing, or one of the Active Record database,
- 422 Unprocessable Entity if the request is missing required parameters
- 404 Not Found if Action Mailbox is not configured to accept inbound emails from Mailgun
- 401 Unauthorized if the request’s signature could not be validated, or if its timestamp is more than 2 minutes old
- 204 No Content if an inbound email is successfully recorded and enqueued for routing to the appropriate mailbox
Returns:
Authenticates requests by validating their signatures.
- signature: A hexadecimal HMAC-SHA256 of the timestamp concatenated with the token, generated using the Mailgun Signing key
- token: A randomly-generated, 50-character string
- timestamp: The current time according to Mailgun as the number of seconds passed since the UNIX epoch
- body-mime: The full RFC 822 message
Ingests inbound emails from Mailgun. Requires the following parameters:

def authenticate 

def authenticate
  head :unauthorized unless authenticated?
end

def authenticated? 

def authenticated?
  if key.present?
    Authenticator.new(
      key:       key,
      timestamp: params.require(:timestamp),
      token:     params.require(:token),
      signature: params.require(:signature)
    ).authenticated?
  else
    raise ArgumentError, <<~MESSAGE.squish
      Missing required Mailgun Signing key. Set action_mailbox.mailgun_signing_key in your application's
      encrypted credentials or provide the MAILGUN_INGRESS_SIGNING_KEY environment variable.
    MESSAGE
  end
end

def create 

def create
  ActionMailbox::InboundEmail.create_and_extract_message_id! mail
end

def key 

def key
  Rails.application.credentials.dig(:action_mailbox, :mailgun_signing_key) || ENV["MAILGUN_INGRESS_SIGNING_KEY"]
end

def mail 

def mail
  params.require("body-mime").tap do |raw_email|
    raw_email.prepend("X-Original-To: ", params.require(:recipient), "\n") if params.key?(:recipient)
  end
end