Rails 3.0.10和Heroku的Paypal IPN 503错误

Question

I'm trying to integrate Paypal IPN notifications in a Rails 3.0.10 application which is deployed to Heroku (bamboo-mri-1.9.2). It's not the first time I integrate IPN on a Rails application, but I'm having a problem that is driving me mad and I'm clueless at this moment.

I have defined a special route for IPN at config/routes.rb:

match "/paypal_ipn" => "registrations#paypal_ipn", :as => :paypal_ipn

And I have the corresponding action in RegistrationController:

class RegistrationsController < ApplicationController
  include ActiveMerchant::Billing::Integrations
  ...
  def paypal_ipn
    // Notification management stuff...
  end
end

The problem is that I'm unable to send an IPN notification to this URL once the application is deployed to Heroku, as the server always responds to the IPN simulator with a 503 Error. The curious thing is that I can send any POST or GET requests to this URL successfully using CURL or any browser.

I've even replaced the paypal_ipn method's content by a raise "It exploded!" without any exception raised to the log, and skipped all the before filters I've seen around with same results.

All I can see on heroku logs is this, but it doesn't helps me much...

2012-05-20T17:32:47+00:00 heroku[router]: Error H13 (Connection closed without response) -
> POST reddeportiva-sta.heroku.com/paypal_ipn dyno=web.1 queue= wait= service= status=503 
bytes=2012-05-20T17:32:47+00:00 app[web.1]: !! Unexpected error while processing request: 
undefined method `include?' for nil:NilClass
2012-05-20T17:32:47+00:00 heroku[nginx]: 173.0.82.126 - - [20/May/2012:17:32:47 +0000] 
"POST /paypal_ipn HTTP/1.0" 503 607 "-" "-" reddeportiva-sta.heroku.com

Anybody knows if Paypal IPN notification messages have anything in particular which is different from a simple CURL POST request which could be causing this nightmare?

EDIT Well, I've discovered the source of the problem, but I'm still investigating for a solution.

I'm using rack-iframe ( http://rubygems.org/gems/rack-iframe ) to let my users login and maintain sessions inside an iframe on their webpages.

It seems there is something on the Paypal IPN message that is making rack-iframe crash. I'll investigate it further and share my discoverings.

That was a really weird bug...

---

EDIT 2 I've sent a pull request with a little fix for this issue to rack-iframe creator, so I think this problem is solved :-) https://github.com/merchii/rack-iframe/pull/1

Answer 1

The "undefined method `include?' for nil:NilClass" is curious, I would jack up the logging level to DEBUG and see what else is going on:

https://devcenter.heroku.com/articles/logging#logging_in_rails