Allow configuration of callback host from Rails controller

lib/mandrill-rails/web_hook_processor.rb

@@ -31,6 +31,8 @@
 #   end
 #
 module Mandrill::Rails::WebHookProcessor
+  Undefined = Object.new.freeze
+
   extend ActiveSupport::Concern
 
   included do
@@ -71,6 +73,15 @@ def on_unhandled_mandrill_events!(new_setting=nil)
       @on_unhandled_mandrill_events
     end
 
+    # Sets or gets the callback host
+    def callback_host(callback_host = Undefined)
+      if Undefined === callback_host
+        @callback_host
+      else
+        @callback_host = callback_host
+      end
+    end
+
     def ignore_unhandled_events!
       on_unhandled_mandrill_events! :ignore
     end
@@ -90,7 +101,10 @@ def show
 
   # Handles controller :create action (corresponds to a POST from Mandrill).
   def create
-    processor = Mandrill::WebHook::Processor.new(params, self)
+    processor = Mandrill::WebHook::Processor.new(
+      params,
+      self.class.callback_host || self
+    )
     processor.on_unhandled_mandrill_events = self.class.on_unhandled_mandrill_events!
     processor.run!
     head(:ok)

spec/mandrill-rails/web_hook_processor_spec.rb

@@ -98,6 +98,34 @@ def head(*args) ; end
       processor_instance.create
     end
 
+    context "with a custom callback host" do
+      let(:custom_callback_host) { double('CallbackHost') }
+      let(:params) do
+        {
+          "mandrill_events" => JSON.dump([
+            {
+              "event" => "hard_bounce"
+            }
+          ])
+        }
+      end
+      before do
+        WebHookProcessorTestHarness.callback_host(custom_callback_host)
+        processor_instance.params = params
+      end
+      after do
+        WebHookProcessorTestHarness.callback_host(nil)
+      end
+      it "returns head(:ok) and dispatces the event to callback host" do
+        expect(processor_instance).to receive(:head).with(:ok)
+        expect_any_instance_of(Mandrill::WebHook::Processor).to receive(:on_unhandled_mandrill_events=).with(:log)
+        expect(custom_callback_host).to receive(:handle_hard_bounce).with(
+          Mandrill::WebHook::EventDecorator["event" => "hard_bounce"]
+        )
+        processor_instance.create
+      end
+    end
+
     context "when unhandled events set to raise exceptions" do
       it "delegates the setting to the processor" do
         processor_instance.class.unhandled_events_raise_exceptions!