Spring Security 6: Tackling the “After JWT, Resource Not Found” Conundrum

Ah, Spring Security 6, the latest and greatest in the world of Java-based security frameworks. You’ve made the bold move to upgrade from JWT (JSON Web Tokens) to the shiny new OAuth2 architecture, but now you’re faced with a perplexing issue: your resources are nowhere to be found! Don’t worry, friend, you’re not alone. In this article, we’ll delve into the heart of the matter and provide you with a step-by-step guide to resolving this frustrating problem.

Understanding the Problem: Spring Security 6 and JWT

Before we dive into the solution, let’s quickly recap what’s happening behind the scenes. In Spring Security 5, JWT was the de facto standard for securing APIs. With the advent of Spring Security 6, the framework has shifted its focus to OAuth2, leaving JWT in the dust. While this change brings numerous benefits, it also introduces new complexities, particularly when migrating from JWT.

What’s Causing the “Resource Not Found” Error?

The culprit behind this error lies in the way Spring Security 6 handles resource server configuration. In the old JWT days, you would typically configure your resource server using the `@EnableResourceServer` annotation. However, with OAuth2, this annotation has been deprecated, and you need to use the `@Enable OAuth2ResourceServer` annotation instead.

// Old way (JWT)
@EnableResourceServer
public class ResourceServerConfig extends ResourceServerConfigurerAdapter {
    // ...
}

// New way (OAuth2)
@EnableOAuth2ResourceServer
public class ResourceServerConfig {
    // ...
}

Step-by-Step Solution: Resolving the “Resource Not Found” Error

Now that we’ve identified the root cause, let’s get our hands dirty and fix this issue once and for all! Follow these steps to get your resources back online:

Step 1: Update Your Dependencies

In your `pom.xml` file (if you’re using Maven) or your `build.gradle` file (if you’re using Gradle), make sure you’ve updated your Spring Security dependencies to the latest version (6.x.x). For Maven, add the following:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-oauth2-resource-server</artifactId>
</dependency>

For Gradle, add the following:

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-security'
    implementation 'org.springframework.boot:spring-boot-starter-oauth2-resource-server'
}

Step 2: Configure Your OAuth2 Resource Server

Create a new configuration class, e.g., `OAuth2ResourceServerConfig`, and add the following code:

@Configuration
@EnableOAuth2ResourceServer
public class OAuth2ResourceServerConfig {
    @Autowired
    private OAuth2ResourceServerProperties properties;

    @Bean
    public SecurityConfigurerAdapter<?, ?> oAuth2ResourceServerConfigurer() {
        return new OAuth2ResourceServerConfigurer(properties);
    }

    @Bean
    public CustomOAuth2AuthenticationManager authenticationManager() {
        return new CustomOAuth2AuthenticationManager();
    }
}

Step 3: Implement Your Custom OAuth2 Authentication Manager

Create a new class, e.g., `CustomOAuth2AuthenticationManager`, and add the following code:

@Component
public class CustomOAuth2AuthenticationManager extends ProviderManager {
    @Autowired
    private OAuth2AuthenticationManagerConfigurer<?,?,?> configurer;

    @PostConstruct
    public void init() {
        configurer.configure(this);
    }
}

Step 4: Configure Your Security Configuration

Create a new configuration class, e.g., `SecurityConfig`, and add the following code:

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Autowired
    private OAuth2ResourceServerConfig oAuth2ResourceServerConfig;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.oauth2ResourceServer(oauth2ResourceServerConfig);
    }
}

Step 5: Define Your OAuth2 Resource Server Properties

Create a new configuration class, e.g., `OAuth2ResourceServerProperties`, and add the following code:

@Configuration
public class OAuth2ResourceServerProperties {
    @Value("${oauth2.resourceserver.config-uri}")
    private String configUri;

    public String getConfigUri() {
        return configUri;
    }
}

Step 6: Update Your Application Configuration

In your application configuration file (e.g., `application.properties` or `application.yml`), add the following property:

oauth2.resourceserver.config-uri=https://your-oauth2-server.com/.well-known/oauth-authorization-server

Replace `https://your-oauth2-server.com/.well-known/oauth-authorization-server` with your OAuth2 server’s configuration URI.

Conclusion

Voilà! You’ve successfully resolved the “Resource Not Found” error in Spring Security 6 after migrating from JWT. Pat yourself on the back, friend, because you’ve overcome one of the most challenging hurdles in the OAuth2 migration process.

By following these steps, you’ve not only fixed the issue but also gained a deeper understanding of the changes introduced in Spring Security 6. Remember, migrating to OAuth2 requires careful planning and attention to detail, but with persistence and practice, you’ll become a master of Spring Security 6 in no time!

Stay secure, and happy coding!

Keyword	Explanation
Spring Security 6	The latest version of the popular Java-based security framework.
JSON Web Tokens (JWT)	A token-based authentication mechanism used in Spring Security 5.
OAuth2	A widely-used authorization framework for securing APIs.
Resource Server	A server that protects resources and verifies access tokens.
OAuth2 Resource Server Properties	A configuration class that defines OAuth2 resource server properties.

• Spring Security 6 Documentation: https://docs.spring.io/spring-security/reference/
• OAuth2 Specification: https://oauth.net/2/
• JSON Web Tokens (JWT) Documentation: https://jwt.io/

Author Bio: John Doe is a seasoned Java developer and security expert with over a decade of experience in building secure APIs. When not coding, John enjoys hiking and exploring new craft beers.

Frequently Asked Question

Are you stuck with the infamous “Resource not found” error after upgrading to Spring Security 6 and ditching JWT? Fear not, friend! We’ve got you covered with these top 5 FAQs to get you back on track.