Add Mailgun endpoint for receiving email tasks via Mailgun

app/controllers/mailgun_controller.rb

@@ -0,0 +1,38 @@
+require 'openssl'
+
+class MailgunController < ApplicationController
+
+  skip_before_filter :login_required, :only => [:mailgun]
+  before_filter :verify, :only => [:mailgun]
+  protect_from_forgery with: :null_session
+
+  def mailgun
+    unless params.include? 'body-mime'
+      Rails.logger.info "Cannot process Mailgun request, no body-mime sent"
+      render_failure "Unacceptable body-mime", 406
+      return
+    end
+
+    todo = MessageGateway.receive(params['body-mime'])
+    if todo
+      render :xml => todo.to_xml( *todo_xml_params )
+    else
+      render_failure "Todo not saved", 406
+    end
+  end
+
+  private
+
+  def verify
+    unless params['signature'] == OpenSSL::HMAC.hexdigest(
+            OpenSSL::Digest::Digest.new('sha256'),
+            SITE_CONFIG['mailgun_api_key'],
+            '%s%s' % [params['timestamp'], params['token']]
+         )
+      Rails.logger.info "Cannot verify Mailgun signature"
+      render_failure "Access denied", 406
+      return
+    end
+  end
+
+end