Spring boot, oAuth2 sign up with facebook

Question

I have been following @Dave Syers' excellent tutorial on Spring boot and oAuth2

I have been able to create a log in function, so that protected resources need a login to facebook before they can be accessed.

But now I am trying to create a "sign up" page. On stackoverflow, for example, there is an option to sign up with facebook, so your details are sent to Stackoverflow.com from facebook. How can this be performed with oAuth2? I was able to do this with spring-social, but I cannot wrap my head around how to do this with a direct oauth2 approach.

Please help?

Answer 1

The answer was simpler than I expected. All I needed to do was add my custom AuthenticationSuccessHandler to the filter:

All I had to do was add an AuthenticationSuccessHandler handle to the method that returns a Filter ssoFilter()

@Autowired
private CustomAuthenticationSuccessHandler customAuthenticationSuccessHandler;


private Filter ssoFilter() {
    OAuth2ClientAuthenticationProcessingFilter facebookFilter = new OAuth2ClientAuthenticationProcessingFilter("/login/facebook");
    OAuth2RestTemplate facebookTemplate = new OAuth2RestTemplate(facebook(), oauth2ClientContext);
    facebookFilter.setRestTemplate(facebookTemplate);
    facebookFilter.setTokenServices(new UserInfoTokenServices(facebookResource().getUserInfoUri(), facebook().getClientId()));
    facebookFilter.setAuthenticationSuccessHandler(customAuthenticationSuccessHandler);
    return facebookFilter;
} 

And my CustomAuthenticationSuccessHandler was just a component that extended AuthenticationSuccessHandler

@Component
public class CustomAuthenticationSuccessHandler implements AuthenticationSuccessHandler {

@Override
public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response,
                                    Authentication authentication) throws IOException, ServletException {
    //implementation
}

}

So in my sign up page, I could simply use the same login action, but in the success handler I created the User and stored her in the DB