SpringSecurity - Custom automatic authentication

Question

This is my scenario:

• a web-app perform a sort-of SSO for many applications
• logged-in user than click on a link and the app makes a post with user info

Answer 1

For sake of completeness, in Spring Security 4 things are slightly changed. For example, the Java configuration is highly recommended. In this way, it's easier to integrate with Spring Boot.

It follows the Java Configuration that is equivalent to the XML configuration given in the above answers.

@Configuration
@EnableWebSecurity
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.addFilterBefore(customAuthFilter(), AbstractPreAuthenticatedProcessingFilter.class)
            .authenticationProvider(preauthAuthProvider())
            .authorizeRequests()
            .anyRequest().authenticated();
    }

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth.authenticationProvider(preauthAuthProvider());
    }

    @Bean
    public PreAuthenticatedAuthenticationProvider preauthAuthProvider() {
        PreAuthenticatedAuthenticationProvider preauthAuthProvider =
            new PreAuthenticatedAuthenticationProvider();
                preauthAuthProvider.setPreAuthenticatedUserDetailsService(
                    userDetailsServiceWrapper());
        return preauthAuthProvider;
    }

    @Bean
    public OnlyRolesPreAuthenticatedUserDetailsService userDetailsServiceWrapper() {
        OnlyRolesPreAuthenticatedUserDetailsService service =
            new MyPreAuthenticatedUserDetailsService();
        return service;
    }

    @Bean
    public MyPreAuthenticatedProcessingFilter customAuthFilter() throws Exception {
        MyPreAuthenticatedProcessingFilter filter = new MyPreAuthenticatedProcessingFilter();
        filter.setAuthenticationManager(authenticationManager());
        return filter;
    }
}

I think that the above code is worth, because examples in internet are very basic and the Spring documentation lacks of such details.