Role-based Authentication Not Working with Keycloak and Java Spring? Here’s the Fix!

Are you tearing your hair out trying to get role-based authentication working with Keycloak and Java Spring? You’re not alone! In this article, we’ll dive into the common pitfalls and provide a step-by-step guide to help you get it working in no time.

The Problem: Keycloak and Java Spring Not Playing Nice

Keycloak is a fantastic Identity and Access Management (IAM) solution, and Java Spring is a popular framework for building robust applications. However, when you try to integrate the two, things can get messy. Specifically, role-based authentication seems to be the Achilles’ heel for many developers.

What’s Going Wrong?

Before we dive into the solution, let’s identify the common issues that might be causing the problem:

• Incorrect configuration of Keycloak realm and clients
• Missing or incorrect dependencies in the Java Spring project
• Misconfigured security settings in the application.properties file
• Incorrect usage of annotations and authorization settings in the Java code

Setting Up Keycloak and Java Spring for Role-Based Authentication

Let’s start from scratch and set up a new Keycloak realm and client, along with a Java Spring project.

Step 1: Create a Keycloak Realm and Client

Log in to your Keycloak instance and create a new realm:

Realm Name: MyRealm
Realm URL: http://localhost:8080/auth

Next, create a new client:

Client ID: myclient
Client Protocol: openid-connect
Root URL: http://localhost:8080/

Step 2: Set Up the Java Spring Project

Create a new Java Spring project using your preferred IDE or by using the Spring Initializr tool.

Add the following dependencies to your pom.xml file:

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

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

Configuring Keycloak and Java Spring for Role-Based Authentication

Now that we have our Keycloak realm and client set up, along with our Java Spring project, let’s configure them for role-based authentication.

Step 1: Configure the application.properties File

Add the following properties to your application.properties file:

keycloak.realm=MyRealm
keycloak.auth-server-url=http://localhost:8080/auth
keycloak.resource=myclient
keycloak.public-client=true
keycloak.principal-attribute=preferred_username

Step 2: Configure the Security Configuration

Create a new configuration class that extends the WebSecurityConfigurerAdapter:

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private KeycloakConfigurerAdapter keycloakConfigurerAdapter;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.oauth2Login()
                .oauth2AuthorizedGrantTypes("openid", "profile", "email")
                .userInfoEndpointUrl("/userinfo")
                .userNameAttribute("sub")
                .and()
                .oauth2AuthorizedGrantTypes("password", "authorization_code", "refresh_token")
                .userInfoEndpointUrl("/userinfo")
                .userNameAttribute("sub")
                .and()
                .authorizeRequests()
                .antMatchers("/api/admin/**").hasRole("ADMIN")
                .antMatchers("/api/user/**").hasRole("USER")
                .anyRequest().authenticated();
    }
}

Step 3: Secure Your API Endpoints

Use the @Secured annotation to secure your API endpoints:

@RestController
@RequestMapping("/api/admin")
public class AdminController {

    @GetMapping("/users")
    @Secured("ROLE_ADMIN")
    public List<User> getUsers() {
        // Return a list of users
    }
}

@RestController
@RequestMapping("/api/user")
public class UserController {

    @GetMapping("/profile")
    @Secured("ROLE_USER")
    public Profile getUserProfile() {
        // Return the user's profile
    }
}

Troubleshooting Common Issues

Despite following the above steps, you might still encounter issues. Here are some common problems and their solutions:

Issue 1: Keycloak Realm Not Found

If you’re getting a “Realm not found” error, check that:

• The realm name matches the one configured in the application.properties file
• The Keycloak instance is running and accessible

Issue 2: User Roles Not Being Resolved

If the user roles are not being resolved, check that:

• The Keycloak client is configured to use the correct realm
• The user has the correct roles assigned in the Keycloak realm
• The security configuration is correctly set up to use the Keycloak adapter

Conclusion

Role-based authentication with Keycloak and Java Spring can be a complex topic, but by following the steps outlined in this article, you should be able to get it working in no time. Remember to double-check your configuration, dependencies, and security settings to ensure everything is set up correctly.

Still stuck? Try checking the Keycloak and Java Spring documentation, or seek help from online communities and forums.

Additional Resources

For further reading and troubleshooting, refer to the following resources:

• Keycloak Documentation: https://www.keycloak.org/documentation
• Java Spring Documentation: https://spring.io/docs
• Keycloak and Java Spring Tutorials: https://github.com/keycloak/keycloak-quickstarts/tree/latest/spring-boot-2

Keycloak Version	Java Spring Version
12.0.0	2.4.3

Tested Environment:

This article was written and tested using Keycloak version 12.0.0 and Java Spring version 2.4.3. Your mileage may vary with different versions, so be sure to check the documentation for your specific versions.

Final Thoughts

Implementing role-based authentication with Keycloak and Java Spring requires attention to detail and a solid understanding of both technologies. By following this guide, you should be able to overcome the common pitfalls and get your application up and running with secure role-based access control.

Happy coding!

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