Extra slashes in CORS requests causes rack/cors errors on Heroku as of 07/25

gistfile1.txt

Last night CORS requests stopped working for us on Heroku. We are using rack-cors (0.2.8) middleware.

It rurns out our request paths didn't match our rackup configuration. 
The real question might be: why were these  requests returning correct HTTP headers in the past?  
One hypothesis is that some other processes was cleaning up requests with redundant slashes.

The configuration:

#…
require 'rack/cors'
use Rack::Cors do
  allow do
    origins '*'
    resource '/shutterbug/*', :headers => :any, :methods => :any
  end
end
#…

# Requests that USED to work, but stopped working (note the dubble slash // ):
curl -H "Origin: http://example.com" --verbose \
  http://shutterbug.herokuapp.com//shutterbug/make_snapshot

# Requests that DO work now for us:
curl -H "Origin: http://example.com" --verbose \
  http://shutterbug.herokuapp.com/shutterbug/make_snapshot