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 API key in the MAILGUN_INGRESS_API_KEY environment variable.
mailgun_api_key: …
action_mailbox:
action_mailbox.mailgun_api_key, where Action Mailbox will automatically find it:
Use rails credentials:edit to add your API key to your application’s encrypted credentials under
so it can authenticate requests to the Mailgun ingress.
1. 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-]

== Usage
the Active Storage service, or the Active Job backend is misconfigured or unavailable
- 500 Server Error if the Mailgun API 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 API 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 API key. Set action_mailbox.mailgun_api_key in your application's
      encrypted credentials or provide the MAILGUN_INGRESS_API_KEY environment variable.
    MESSAGE
  end
end

def create 

def create
  ActionMailbox::InboundEmail.create_and_extract_message_id! params.require("body-mime")
end

def key 

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