"Forbidden" message is shown when I access a Sinatra app on AppFog

Question

I uploaded a simple Sinatra app to AppFog. It worked well on my local machine. But after uploading the app to AppFog, a page with "Forbidden" message is shown when I access to AppFog domain.

These are appFog logs:

====> /logs/stderr.log <====
...
W, [2012-06-01T06:32:54.008426 #28933]  WARN -- : attack prevented by Rack::Protection::IPSpoofing
211.32.146.42 - - [01/Jun/2012 06:32:54] "GET / HTTP/1.1" 403 - 0.0002
10.0.64.157 - - [01/Jun/2012:06:32:54 UTC] "GET / HTTP/1.0" 403 9 - -> /
W, [2012-06-01T06:32:54.393022 #28933]  WARN -- : attack prevented by Rack::Protection::IPSpoofing
211.32.146.42 - - [01/Jun/2012 06:32:54] "GET /favicon.ico HTTP/1.1" 403 - 0.0002
10.0.64.157 - - [01/Jun/2012:06:32:54 UTC] "GET /favicon.ico HTTP/1.0" 403 9 - -> /favicon.ico

I did not use Rack::Protection::IPSpoofing in my code, but I get those errors. Rack::Utils is used in helpers block. Is that causing the problem?

The only Ruby code I wrote is following:

require 'sinatra'
require 'data_mapper'
require 'builder'
require 'sinatra/flash'
require 'sinatra/redirect_with_flash'
require 'haml'

enable :sessions

SITE_TITLE = "Recall"
SITE_DESCRIPTION = "'cause you're too busy to remember"

DataMapper::setup(:default, "sqlite3://#{Dir.pwd}/recall.db")

class Note
  include DataMapper::Resource
  property :id, Serial
  property :content, Text, :required => true
  property :complete, Boolean, :required => true, :default => false
  property :created_at, DateTime
  property :updated_at, DateTime
end

DataMapper.finalize.auto_upgrade!

helpers do
  include Rack::Utils
  alias_method :h, :escape_html
end

get '/' do
  @notes = Note.all :order => :id.desc
  @title = 'All Notes'
  if @notes.empty?
    flash[:error] = 'No notes found. Add your first below.'
  end
  haml :home
end

# ...

You can check out the whole source codes here.

How can I solve this problem? Thanks for any advices.

Answer 1

This is an easy fix, try adding this:

set :protection, :except => :ip_spoofing

We are patching our nginx soon to fix this issue, but this work around will help for now.