Adding a Login Screen to a Vaadin Application Using Spring Security

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>

package com.example.application.security;

import com.example.application.views.LoginView;
import com.vaadin.flow.spring.security.VaadinWebSecurityConfigurerAdapter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.builders.WebSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.provisioning.InMemoryUserDetailsManager;

@EnableWebSecurity 1
@Configuration
public class SecurityConfig extends VaadinWebSecurityConfigurerAdapter { 2

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        super.configure(http);

        setLoginView(http, LoginView.class); 3
    }

    /**
     * Allows access to static resources, bypassing Spring security.
     */
    @Override
    public void configure(WebSecurity web) throws Exception {
        web.ignoring().antMatchers("/images/**"); 4
        super.configure(web);
    }

    /**
     * Demo UserDetailService, which only provides two hardcoded
     * in-memory users and their roles.
     * NOTE: This should not be used in real-world applications.
     */
    @Bean
    @Override
    public UserDetailsService userDetailsService() {
        return new InMemoryUserDetailsManager(User.withUsername("user") 5
            .password("{noop}userpass")
            .roles("USER")
            .build());
    }
}

package com.example.application.security;

import com.vaadin.flow.component.UI;
import com.vaadin.flow.server.VaadinServletRequest;
import org.springframework.security.core.context.SecurityContext;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.web.authentication.logout.SecurityContextLogoutHandler;
import org.springframework.stereotype.Component;

@Component
public class SecurityService {

    private static final String LOGOUT_SUCCESS_URL = "/";

    public UserDetails getAuthenticatedUser() {
        SecurityContext context = SecurityContextHolder.getContext();
        Object principal = context.getAuthentication().getPrincipal();
        if (principal instanceof UserDetails) {
            return (UserDetails) principal;
        }
        // Anonymous or no authentication.
        return null;
    }

    public void logout() {
        UI.getCurrent().getPage().setLocation(LOGOUT_SUCCESS_URL);
        SecurityContextLogoutHandler logoutHandler = new SecurityContextLogoutHandler();
        logoutHandler.logout(
                VaadinServletRequest.getCurrent().getHttpServletRequest(), null,
                null);
    }
}

@PermitAll
@Route(value="", layout = MainLayout.class)
@PageTitle("Contacts | Vaadin CRM")
public class ListView extends VerticalLayout {
    // omitted
}

@PermitAll
@Route(value = "dashboard", layout = MainLayout.class)
@PageTitle("Dashboard | Vaadin CRM")
public class DashboardView extends VerticalLayout {
    // omitted
}