JarCastingjava-webapp-authentication
https://github.com/achatain/java-webapp-authentication
#What is it? JWA (Java Webapp Authentication) assists in leveraging Google Sign-In for backend server applications built with Java. Despite being in its early days, JWA provides you with a bunch of robust and easy to use features:
- authentication filter
- sign-in and sign-out servlets
- session management service
- etc.
#How do I integrate it in my backend app?
- Add the dependency in your pom file
<dependency>
<groupId>com.github.achatain</groupId>
<artifactId>java-webapp-authentication</artifactId>
<version>1.1.0</version>
</dependency>
- Install the AuthenticationModule to enable the dependency injection (suggested to use Google Guice)
class AppConfig extends GuiceServletContextListener {
@Override
protected Injector getInjector() {
return Guice.createInjector(
new AuthenticationModule()
);
}
}
- Filter your restricted API through the SessionFilter and serve the sign-in and sign-out servlets
class AppServletModule extends ServletModule {
@Override
protected void configureServlets() {
Map<String, String> initParams = new HashMap<>();
initParams.put(SessionFilter.LOGIN_URL_REDIRECT, "https://myapp.com/google-sign-in/");
filter("/api/*").through(SessionFilter.class, initParams);
serve("/google-auth").with(GoogleSigninServlet.class);
serve("/signout").with(SignOutServlet.class);
}
}
#How do I know who is logged-in? From any servlet filtered through the SessionFilter, you can get the current user thanks to the SessionService
public class MyServlet extends HttpServlet {
private final transient SessionService sessionService;
@Inject
private MyServlet(final SessionService sessionService) {
this.sessionService = sessionService;
}
@Override
protected void doGet(final HttpServletRequest req, final HttpServletResponse resp) throws ServletException, IOException {
AuthenticatedUser user = sessionService.getUserFromSession(req.getSession());
System.out.println("The logged-in user is " + user);
}
}