So44836531Application.java

package com.stackoverflow.so44836531;

import java.io.IOException;

import javax.servlet.*;
import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.*;
import org.springframework.context.annotation.Bean;
import org.springframework.context.event.EventListener;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.SimpleDriverDataSource;
import org.springframework.jdbc.datasource.UserCredentialsDataSourceAdapter;
import org.springframework.security.authentication.event.AuthenticationSuccessEvent;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.User;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.filter.GenericFilterBean;

/**
 * Application properties:
 *
 * spring.datasource.driver-class-name=org.postgresql.Driver
 * spring.datasource.url=jdbc:postgresql://localhost:5432/postgres
 * spring.datasource.username=none
 * spring.datasource.password=none
 *
 * Test with: curl -i -u postgres:postgres1 'localhost:8080/home'
 */

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
public class So44836531Application {

	public static void main(String[] args) {
		SpringApplication.run(So44836531Application.class, args);
	}

	@EnableWebSecurity
	public static class Security extends WebSecurityConfigurerAdapter {
		@Override
		protected void configure(AuthenticationManagerBuilder auth) throws Exception {
			auth.eraseCredentials(false).inMemoryAuthentication().withUser("postgres").password("postgres1").roles("USER");
		}

		@Override
		protected void configure(HttpSecurity http) throws Exception {
			http.httpBasic().and().authorizeRequests().mvcMatchers("/").fullyAuthenticated();
		}
	}

	@Bean
	public UserCredentialsDataSourceAdapter dataSource(DataSourceProperties properties) {
		final UserCredentialsDataSourceAdapter dataSourceAdapter = new UserCredentialsDataSourceAdapter();
		dataSourceAdapter.setTargetDataSource(DataSourceBuilder.create()
				.driverClassName(properties.getDriverClassName())
				.url(properties.getUrl())
				.username(properties.getUsername())
				.password(properties.getPassword())
				.type(SimpleDriverDataSource.class)	// disable pooling
				.build());

		((SimpleDriverDataSource) dataSourceAdapter.getTargetDataSource()).setDriverClass(org.postgresql.Driver.class);	//binder won't set it automatically
		return dataSourceAdapter;
	}

	@Bean
	JdbcTemplate jdbcTemplate(DataSource dataSource) {
		return new JdbcTemplate(dataSource);
	}

	@Component
	public static class DataSourceCredentialsFilter extends GenericFilterBean {
		private final UserCredentialsDataSourceAdapter dataSourceAdapter;

		@Autowired
		public DataSourceCredentialsFilter(UserCredentialsDataSourceAdapter dataSourceAdapter) {
			this.dataSourceAdapter = dataSourceAdapter;
		}

		@Override
		public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
				throws IOException, ServletException {
			final Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
			final User user = (User) authentication.getPrincipal();
			dataSourceAdapter.setCredentialsForCurrentThread(user.getUsername(), user.getPassword());
			chain.doFilter(request, response);
			dataSourceAdapter.removeCredentialsFromCurrentThread();
		}
	}

	@Component
	public static class AuthenticationHandler  {
		private final UserCredentialsDataSourceAdapter dataSourceAdapter;

		@Autowired
		public AuthenticationHandler(UserCredentialsDataSourceAdapter dataSourceAdapter) {
			this.dataSourceAdapter = dataSourceAdapter;
		}

		@EventListener(classes = AuthenticationSuccessEvent.class)
		public void authenticationSuccess(AuthenticationSuccessEvent event) {
			final Authentication authentication = event.getAuthentication();
			final User user = (User) authentication.getPrincipal();
			dataSourceAdapter.setCredentialsForCurrentThread(user.getUsername(), user.getPassword()); // <- the most important part
		}
	}

	@RestController
	public static class Api {
		private final JdbcTemplate jdbcTemplate;

		@Autowired
		public Api(JdbcTemplate jdbcTemplate) { this.jdbcTemplate = jdbcTemplate; }

		@GetMapping("/home")
		public String home() { return jdbcTemplate.queryForObject("select CURRENT_TIMESTAMP", String.class); }
	}
}