Handling the response sent from a ruby on rails application in wordpress

I am using my rails application to send data to a wordpress site. Basically if a user has wrong password, I am going to end the reverse proxy and redirect the user back to the wordpress site but I want to pass data along. In Rails, I use Net::HTTP to send data to another server:

http://ruby-doc.org/stdlib-1.9.3/libdoc/net/http/rdoc/Net/HTTP.html

Now in WordPress I’m not sure how to receive it.

thanks for response