How to send authentication request from client application to server application in rails?

How to send authentication request from client application to server application in rails? We are working on rails application where login is required.On opening of that login page & submitting that form parameters it should send that开发者_运维技巧 submit request to server application for authentication.Is there any mechanism in rails for this client to server communication? Please help us to solve this problem.

There is a simple model based ruby authentication solution called: authlogic

and here is a screencast