FEATURE: support for mandrill webhooks

app/controllers/webhooks_controller.rb

@@ -71,6 +71,23 @@ class WebhooksController < ActionController::Base
     render nothing: true, status: 200
   end
 
+  def mandrill
+    events = params["mandrill_events"]
+    events.each do |event|
+      message_id = event["msg"]["metadata"]["message_id"] rescue nil
+      next unless message_id
+
+      case event["event"]
+      when "hard_bounce"
+        process_bounce(message_id, Email::Receiver::HARD_BOUNCE_SCORE)
+      when "soft_bounce"
+        process_bounce(message_id, Email::Receiver::SOFT_BOUNCE_SCORE)
+      end
+    end
+
+    render nothing: true, status: 200
+  end
+
   private
 
     def mailgun_failure

config/routes.rb

@@ -19,6 +19,7 @@ Discourse::Application.routes.draw do
   post "webhooks/mailgun"  => "webhooks#mailgun"
   post "webhooks/sendgrid" => "webhooks#sendgrid"
   post "webhooks/mailjet"  => "webhooks#mailjet"
+  post "webhooks/mandrill" => "webhooks#mandrill"
 
   if Rails.env.development?
     mount Sidekiq::Web => "/sidekiq"

lib/email/sender.rb

@@ -133,9 +133,12 @@ module Email
       @message.header['X-Discourse-Post-Id']   = nil if post_id.present?
       @message.header['X-Discourse-Reply-Key'] = nil if reply_key.present?
 
-      # it's the only way to pass the original message_id when using mailjet
-      if ActionMailer::Base.smtp_settings[:address][".mailjet.com"]
+      # pass the original message_id when using mailjet/mandrill
+      case ActionMailer::Base.smtp_settings[:address]
+      when /\.mailjet\.com/
         @message.header['X-MJ-CustomID'] = @message.message_id
+      when "smtp.mandrillapp.com"
+        @message.header['X-MC-Metadata'] = { message_id: @message.message_id }.to_json
       end
 
       # Suppress images from short emails

spec/controllers/webhooks_controller_spec.rb

@@ -75,4 +75,28 @@ describe WebhooksController do
 
   end
 
+  context "mandrill" do
+
+    it "works" do
+      user = Fabricate(:user, email: email)
+      email_log = Fabricate(:email_log, user: user, message_id: message_id)
+
+      post :mandrill, mandrill_events: [{
+        "event" => "hard_bounce",
+        "msg" => {
+          "metadata" => {
+            "message_id" => message_id
+          }
+        }
+      }]
+
+      expect(response).to be_success
+
+      email_log.reload
+      expect(email_log.bounced).to eq(true)
+      expect(email_log.user.user_stat.bounce_score).to eq(2)
+    end
+
+  end
+
 end