I couldn’t find a simple, complete example of a spring social application online so I decided to post my own. The resulting app is available on google code and is an example of authenticating a user with Facebook, although a similar approach is applied to Twitter/Linkedin etc.
The app is a standard Spring Web MVC project but some additional configuration is needed to create the beans for interacting with Facebook.
The FacebookWebArgumentResolver is the bean that handles the facebook cookie that gets created when a user authenticates with Facebook.
Setting up javascript authentication with Facebook is very easy using spring social. A tag is provided that does all of the hard work for you. This means that there is no contact with the server for the authentication (the js communicates directly with Facebook which then stores a cookie on the client).
Connect to Facebook
Once the cookie is stored on the client then when they make a request to a page that requires authentication, spring can check the credentials against the facebook cookie.
@RequestMapping(value="auth.do")
public ModelAndView authenticate(@FacebookCookieValue(required=false, value="access_token") String cookie){
if(cookie == null){
return new ModelAndView("authfail");
}
FacebookApi facebook = new FacebookTemplate(cookie);