Un guide rapide sur l'utilisation de Keycloak avec Spring Boot

1. Vue d'ensemble

Dans cet article, nous aborderons les bases de la configuration d'un serveur Keycloak, comment y connecter une application Spring Boot et comment l'utiliser avec Spring Security .

2. Qu'est-ce que Keycloak?

Keycloak est une solution open source de gestion des identités et des accès destinée aux applications et services modernes.

Keycloak offre des fonctionnalités telles que l'authentification unique (SSO), le courtage d'identité et la connexion sociale, la fédération d'utilisateurs, les adaptateurs client, une console d'administration et une console de gestion de compte. Pour en savoir plus sur Keycloak, veuillez visiter la page officielle.

Dans notre didacticiel, nous utiliserons la console d'administration de Keycloak pour configurer, puis nous connecter à Spring Boot à l'aide de l'adaptateur client Keycloak.

3. Configuration d'un serveur Keycloak

3.1. Téléchargement et installation de Keycloak

Vous avez le choix entre plusieurs distributions.

Cependant, dans ce didacticiel, nous utiliserons la version autonome.

Téléchargeons la distribution de serveur autonome Keycloak-11.0.2 à partir de la source officielle.

Une fois que nous avons téléchargé la distribution de serveur autonome, nous pouvons décompresser et démarrer Keycloak à partir du terminal:

unzip keycloak-11.0.2.zip cd keycloak-11.0.2/bin ./standalone.sh -Djboss.socket.binding.port-offset=100

Après avoir exécuté ./standalone.sh , Keycloak démarrera ses services. Une fois que nous verrons une ligne contenant Keycloak 11.0.2 (WildFly Core 12.0.3.Final) démarrée , nous saurons que son démarrage est terminé.

Maintenant, ouvrons un navigateur et visitons // localhost: 8180. Nous serons redirigés vers // localhost: 8180 / auth pour créer une connexion administrative:

Créons un utilisateur administrateur initial nommé initial1 avec le mot de passe zaq1! QAZ . En cliquant sur Créer , nous verrons un message créé par l'utilisateur .

Nous pouvons maintenant passer à la console d'administration. Sur la page de connexion, nous entrerons les informations d'identification de l'utilisateur administrateur initial:

3.2. Créer un royaume

Une connexion réussie nous mènera à la console et ouvrira le royaume maître par défaut pour nous.

Ici, nous allons nous concentrer sur la création d'un royaume personnalisé.

Naviguons vers le coin supérieur gauche pour découvrir le bouton Ajouter un royaume :

Sur l'écran suivant, ajoutons un nouveau domaine appelé SpringBootKeycloak :

Après avoir cliqué sur le bouton Créer , un nouveau royaume sera créé et nous y serons redirigés. Toutes les opérations des sections suivantes seront effectuées dans ce nouveau royaume SpringBootKeycloak .

3.3. Créer un client

Nous allons maintenant accéder à la page Clients. Comme nous pouvons le voir dans l'image ci-dessous, Keycloak est livré avec des clients déjà intégrés :

Mais nous devons ajouter un nouveau client à notre application, nous allons donc cliquer sur Créer . Nous appellerons la nouvelle application de connexion client :

In the next screen, for this tutorial, we'll be leaving all the defaults except the Valid Redirect URIs field. This field should contain the application URL(s) that will use this client for authentication:

Later on, we'll be creating a Spring Boot Application running at the port 8081 that'll use this client. Hence we've used a redirect URL of //localhost:8081/* above.

3.4. Creating a Role and a User

Keycloak uses Role-Based Access. Therefore, each user must have a role.

To do that, we need to navigate to the Roles page:

Then, we'll add the user role:

Now we've got a role that can be assigned to users, but there are no users yet. So let's go the Users page and add one:

We'll add a user named user1:

Once the user is created, a page with its details will be displayed:

We can now go to the Credentials tab. We'll be setting the initial password to [email protected]:

Finally, we'll navigate to the Role Mappings tab. We'll be assigning the user role to our user1:

4. Generating Access Tokens with Keycloak's API

Keycloak provides a REST API for generating and refreshing access tokens. We can easily use this API to create our own login page.

First, we need to acquire an access token from Keycloak by sending a POST request to this URL:

//localhost:8180/auth/realms/master/protocol/openid-connect/token

The request should have this JSON body:

{     'client_id': 'your_client_id', 'username': 'your_username', 'password': 'your_password', 'grant_type': 'password' }

In response, we'll get an access_token and a refresh_token.

The access token should be used in every request to a Keycloak-protected resource by simply placing it in the Authorization header:

headers: {     'Authorization': 'Bearer' + access_token }

Once the access token has expired, we can refresh it by sending a POST request to the same URL as above, but containing the refresh token instead of username and password:

{     'client_id': 'your_client_id', 'refresh_token': refresh_token_from_previous_request, 'grant_type': 'refresh_token' }

Keycloak will respond to this with a new access_token and refresh_token.

5. Creating a Spring Boot Application

5.1. Dependencies

The latest Spring Boot Keycloak Starter dependencies can be found on Maven Central.

The Keycloak Spring Boot adaptercapitalizes on Spring Boot’s auto-configuration, so all we need to do is add the Keycloak Spring Boot starter to our project.

Within the dependencies XML element, we need the following to run Keycloak with Spring Boot:

 org.keycloak keycloak-spring-boot-starter  

After the dependencies XML element, we need to specify dependencyManagement for Keycloak:

   org.keycloak.bom keycloak-adapter-bom 11.0.2 pom import   

The following embedded containers are supported now and don't require any extra dependencies if using Spring Boot Keycloak Starter:

  • Tomcat
  • Undertow
  • Jetty

5.2. Thymeleaf Web Pages

We're using Thymeleaf for our web pages.

We've got three pages:

  • external.html – an externally facing web page for the public
  • customers.html – an internally facing page that will have its access restricted to only authenticated users with the role user.
  • layout.html – a simple layout, consisting of two fragments, that is used for both the externally facing page and the internally facing page

The code for the Thymeleaf templates is available on Github.

5.3. Controller

The web controller maps the internal and external URLs to the appropriate Thymeleaf templates:

@GetMapping(path = "/") public String index() { return "external"; } @GetMapping(path = "/customers") public String customers(Principal principal, Model model) { addCustomers(); model.addAttribute("customers", customerDAO.findAll()); model.addAttribute("username", principal.getName()); return "customers"; }

For the path /customers, we're retrieving all customers from a repository and adding the result as an attribute to the Model. Later on, we iterate through the results in Thymeleaf.

To be able to display a username, we're injecting the Principal as well.

Note that we're using customer here just as raw data to display, and nothing more.

5.4. Keycloak Configuration

Here's the basic, mandatory configuration:

keycloak.auth-server-url=//localhost:8180/auth keycloak.realm=SpringBootKeycloak keycloak.resource=login-app keycloak.public-client=true 

As we recall, we started Keycloak on port 8180, hence the path specified in keycloak.auth-server-url. We enter the realm name we created in the Keycloak admin console.

The value we specify in keycloak.resource matches the client we named in the admin console.

Here are the security constraints we'll be using:

keycloak.security-constraints[0].authRoles[0]=user keycloak.security-constraints[0].securityCollections[0].patterns[0]=/customers/*

These constraints ensure that every request to /customers/* will only be authorized if the one requesting it is an authenticated user with the role user.

Additionally, we can define keycloak.principal-attribute as preferred_username so as to populate our controller's Principal with a proper user:

keycloak.principal-attribute=preferred_username

5.5. Demonstration

Now, we're ready to test our application. To run a Spring Boot application, we can start it easily through an IDE like Spring Tool Suite (STS) or run this command in the terminal:

mvn clean spring-boot:run

On visiting //localhost:8081 we see:

Now we click customers to enter the intranet, which is the location of sensitive information.

We can see that we've been redirected to authenticate through Keycloak to see if we're authorized to view this content:

Once we log in as user1, Keycloak will verify our authorization – that we have the user role – and we'll be redirected to the restricted customers page:

Now we've finished the set up of connecting Spring Boot with Keycloak and demonstrating how it works.

As we can see, the entire process of calling the Keycloak Authorization Server was handled seamlessly by Spring Boot for us. We did not have to call the Keycloak API to generate the Access Token ourselves, or even send the Authorization header explicitly in our request for protected resources.

Next, we'll be reviewing how to use Spring Security in conjunction with our existing application.

6. Spring Security

There is a Keycloak Spring Security Adapter, and it’s already included in our Spring Boot Keycloak Starter dependency. We'll now see how to integrate Spring Security with Keycloak.

6.1. Dependency

To use Spring Security with Spring Boot, we must add this dependency:

 org.springframework.boot spring-boot-starter-security 2.2.6.RELEASE 

The latest Spring Boot Starter Security release can be found on Maven Central.

6.2. Configuration Class

Keycloak provides a KeycloakWebSecurityConfigurerAdapter as a convenient base class for creating a WebSecurityConfigurer instance.

This is helpful because any application secured by Spring Security requires a configuration class that extends WebSecurityConfigurerAdapter:

@Configuration @EnableWebSecurity @ComponentScan(basePackageClasses = KeycloakSecurityComponents.class) class SecurityConfig extends KeycloakWebSecurityConfigurerAdapter { @Autowired public void configureGlobal( AuthenticationManagerBuilder auth) throws Exception { KeycloakAuthenticationProvider keycloakAuthenticationProvider = keycloakAuthenticationProvider(); keycloakAuthenticationProvider.setGrantedAuthoritiesMapper( new SimpleAuthorityMapper()); auth.authenticationProvider(keycloakAuthenticationProvider); } @Bean public KeycloakSpringBootConfigResolver KeycloakConfigResolver() { return new KeycloakSpringBootConfigResolver(); } @Bean @Override protected SessionAuthenticationStrategy sessionAuthenticationStrategy() { return new RegisterSessionAuthenticationStrategy( new SessionRegistryImpl()); } @Override protected void configure(HttpSecurity http) throws Exception { super.configure(http); http.authorizeRequests() .antMatchers("/customers*") .hasRole("user") .anyRequest() .permitAll(); } }

In the code above, the method configureGlobal() tasks the SimpleAuthorityMapper to make sure roles are not prefixed with ROLE_.

Another method, keycloakConfigResolver defines that we want to use the Spring Boot properties file support instead of the default keycloak.json.

Because we've set up the security constraints with Spring Security, we can remove or comment these security constraints we'd placed earlier in the properties file:

#keycloak.security-constraints[0].authRoles[0]=user #keycloak.security-constraints[0].securityCollections[0].patterns[0]=/customers/*

Now, after we authenticate, we'll be able to access the internal customers' page, same as we saw before.

7. Conclusion

In this tutorial, we’ve configured a Keycloak server and used it with a Spring Boot Application.

Nous avons également vu comment configurer Spring Security et l'utiliser en conjonction avec Keycloak. Une version fonctionnelle du code présenté dans cet article est disponible à l'adresse over sur Github.