Add notifications to ActionDispatch::ShowExceptions, this can be used as hooks for plugins like ExceptionNotifier.

1 files changed, 22 insertions, 2 deletions

diff --git a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
index 4ebc8a2ab9..af356707c6 100644
--- a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
@@ -1,7 +1,24 @@
 require 'active_support/core_ext/exception'
+require 'active_support/notifications'
 require 'action_dispatch/http/request'
 
 module ActionDispatch
+  # This middleware rescues any exception returned by the application and renders
+  # nice exception pages if it's being rescued locally.
+  #
+  # Every time an exception is caught, a notification is published, becoming a good API
+  # to deal with exceptions. So, if you want send an e-mail through ActionMailer
+  # everytime this notification is published, you just need to do the following:
+  #
+  #   ActiveSupport::Notifications.subscribe "action_dispatch.show_exception" do |name, start, end, instrumentation_id, payload|
+  #     ExceptionNotifier.deliver_exception(start, payload)
+  #   end
+  #
+  # The payload is a hash which has to pairs:
+  #
+  # * :env - Contains the rack env for the given request;
+  # * :exception - The exception raised;
+  #
   class ShowExceptions
     LOCALHOST = '127.0.0.1'.freeze
 
@@ -44,8 +61,11 @@ module ActionDispatch
     def call(env)
       @app.call(env)
     rescue Exception => exception
-      raise exception if env['action_dispatch.show_exceptions'] == false
-      render_exception(env, exception)
+      ActiveSupport::Notifications.instrument 'action_dispatch.show_exception',
+        :env => env, :exception => exception do
+        raise exception if env['action_dispatch.show_exceptions'] == false
+        render_exception(env, exception)
+      end
     end
 
     private