Add basic, unauthenticated inbound emails controller

app/controllers/action_mailroom/inbound_emails_controller.rb

@@ -0,0 +1,14 @@
+class ActionMailroom::InboundEmailsController < ActionController::Base
+  skip_forgery_protection
+  before_action :require_rfc822_message
+
+  def create
+    ActionMailroom::InboundEmail.create!(raw_email: params[:message])
+    head :created
+  end
+
+  private
+    def require_rfc822_message
+      head :unsupported_media_type unless params.require(:message).content_type == 'message/rfc822'
+    end
+end

config/routes.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+Rails.application.routes.draw do
+  scope :action_mailroom do
+    post "/inbound_emails" => "action_mailroom/inbound_emails#create", as: :rails_inbound_emails
+  end
+end

test/unit/controller_test.rb

@@ -0,0 +1,19 @@
+require_relative '../test_helper'
+
+class ActionMailroom::InboundEmailsControllerTest < ActionDispatch::IntegrationTest
+  test "receiving a valid RFC 822 message" do
+    assert_difference -> { ActionMailroom::InboundEmail.count }, +1 do
+      post_inbound_email "welcome.eml"
+    end
+
+    assert_response :created
+
+    inbound_email = ActionMailroom::InboundEmail.last
+    assert_equal file_fixture('../files/welcome.eml').read, inbound_email.raw_email.download
+  end
+
+  private
+    def post_inbound_email(fixture_name)
+      post rails_inbound_emails_url, params: { message: fixture_file_upload("files/#{fixture_name}", 'message/rfc822') }
+    end
+end