Added jwt token validation and api endpoint versioning

src/main/java/auth_service/configuration/security/JwtAuthenticationFilter.java

@@ -0,0 +1,64 @@
+package auth_service.configuration.security;
+
+import jakarta.servlet.FilterChain;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.jspecify.annotations.NonNull;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;
+import org.springframework.stereotype.Component;
+import org.springframework.web.filter.OncePerRequestFilter;
+
+import java.io.IOException;
+import java.util.Collections;
+
+@Component
+@RequiredArgsConstructor
+@Slf4j
+public class JwtAuthenticationFilter extends OncePerRequestFilter {
+
+    private final JwtService jwtService;
+
+    @Override
+    protected void doFilterInternal(
+            HttpServletRequest request,
+            @NonNull HttpServletResponse response,
+            @NonNull FilterChain filterChain
+    ) throws ServletException, IOException {
+
+        final String authHeader = request.getHeader("Authorization");
+
+        if (authHeader == null || !authHeader.startsWith("Bearer ")) {
+            filterChain.doFilter(request, response);
+            return;
+        }
+
+        final String jwt = authHeader.substring(7);
+        if (!jwtService.isTokenValid(jwt)) {
+            filterChain.doFilter(request, response);
+            return;
+        }
+
+        try {
+            final String userEmail = jwtService.extractEmail(jwt);
+
+            if (userEmail != null && SecurityContextHolder.getContext().getAuthentication() == null) {
+                UsernamePasswordAuthenticationToken authToken = new UsernamePasswordAuthenticationToken(
+                        userEmail,
+                        null,
+                        Collections.emptyList()
+                );
+                authToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
+                SecurityContextHolder.getContext().setAuthentication(authToken);
+            }
+        } catch (Exception e) {
+            log.error("JWT Validation failed: {}", e.getMessage());
+        }
+
+        filterChain.doFilter(request, response);
+    }
+}

src/main/java/auth_service/configuration/security/JwtConfig.java

@@ -0,0 +1,15 @@
+package auth_service.configuration.security;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+@Getter
+@Setter
+@Configuration
+@ConfigurationProperties(prefix = "security.jwt")
+public class JwtConfig {
+
+    private String secret;
+}

src/main/java/auth_service/configuration/security/JwtService.java

@@ -0,0 +1,70 @@
+package auth_service.configuration.security;
+
+import auth_service.domain.login.model.User;
+import io.jsonwebtoken.Jwts;
+import io.jsonwebtoken.security.Keys;
+import org.springframework.stereotype.Service;
+
+import javax.crypto.SecretKey;
+import java.nio.charset.StandardCharsets;
+import java.util.Date;
+
+/**
+ * Service responsible for generating and validating JSON Web Tokens (JWT).
+ */
+@Service
+public class JwtService {
+
+    // Token validity: 24 hours in milliseconds
+    private static final long JWT_EXPIRATION_MS = 86400000;
+    private final JwtConfig jwtConfig;
+
+    public JwtService(JwtConfig jwtConfig) {
+        this.jwtConfig = jwtConfig;
+    }
+
+    /**
+     * Generates a secure JWT for the authenticated user.
+     * * @param user The authenticated user entity
+     *
+     * @return A signed JWT string
+     */
+    public String generateToken(User user) {
+        return Jwts.builder()
+                .subject(user.getEmail())
+                .issuedAt(new Date(System.currentTimeMillis()))
+                .expiration(new Date(System.currentTimeMillis() + JWT_EXPIRATION_MS))
+                .signWith(getSigningKey())
+                .compact();
+    }
+
+    public String extractEmail(String token) {
+        return Jwts.parser()
+                .verifyWith(getSigningKey())
+                .build()
+                .parseSignedClaims(token)
+                .getPayload()
+                .getSubject();
+    }
+
+    public boolean isTokenValid(String token) {
+        try {
+            Jwts.parser()
+                    .verifyWith(getSigningKey())
+                    .build()
+                    .parseSignedClaims(token);
+            return true;
+        } catch (Exception _) {
+            return false;
+        }
+    }
+
+    /**
+     * Retrieves the cryptographic key used for signing the token.
+     */
+    private SecretKey getSigningKey() {
+        String secretKey = jwtConfig.getSecret();
+        byte[] keyBytes = secretKey.getBytes(StandardCharsets.UTF_8);
+        return Keys.hmacShaKeyFor(keyBytes);
+    }
+}

src/main/java/auth_service/configuration/security/SecurityConfig.java

@@ -1,5 +1,6 @@
-package auth_service.configuration;
+package auth_service.configuration.security;
 
+import lombok.RequiredArgsConstructor;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -10,6 +11,7 @@ import org.springframework.security.config.http.SessionCreationPolicy;
 import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.cors.CorsConfigurationSource;
 import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
@@ -23,6 +25,7 @@ import java.util.List;
  */
 @Configuration
 @EnableWebSecurity
+@RequiredArgsConstructor
 public class SecurityConfig {
 
     /**
@@ -34,6 +37,9 @@ public class SecurityConfig {
             "/actuator/prometheus",   // Allow Prometheus to scrape metrics
             "/error"                  // Default Spring Boot error page routing
     };
+
+    private final JwtAuthenticationFilter jwtAuthFilter;
+
     /**
      * Injects the allowed CORS origins from the active application.yml profile.
      */
@@ -78,7 +84,8 @@ public class SecurityConfig {
                 .authorizeHttpRequests(auth -> auth
                         .requestMatchers(WHITE_LIST_URLS).permitAll()
                         .anyRequest().authenticated()
-                );
+                )
+                .addFilterBefore(jwtAuthFilter, UsernamePasswordAuthenticationFilter.class);
 
         return http.build();
     }

src/main/java/auth_service/domain/login/controller/LoginController.java

@@ -33,7 +33,7 @@ public class LoginController {
     public ResponseEntity<LoginResponse> login(@RequestBody LoginRequest request) {
 
         var user = ApiMapper.toModel(request);
-        loginService.login(user);
-        return ResponseEntity.ok(new LoginResponse("Login successful", user.getEmail()));
+        var jwt = loginService.login(user);
+        return ResponseEntity.ok(new LoginResponse("Login successful", jwt));
     }
 }

src/main/java/auth_service/domain/login/service/LoginService.java

@@ -1,5 +1,6 @@
 package auth_service.domain.login.service;
 
+import auth_service.configuration.security.JwtService;
 import auth_service.domain.login.exception.InvalidCredentialsException;
 import auth_service.domain.login.exception.UserNotFoundException;
 import auth_service.domain.login.model.User;
@@ -15,14 +16,18 @@ import org.springframework.stereotype.Service;
 public class LoginService {
     private final UserRepository userRepository;
     private final PasswordEncoder passwordEncoder;
+    private final JwtService jwtService;
 
     public String login(User userToLogin) {
         var userEntity = userRepository.findByEmail(userToLogin.getEmail()).orElseThrow(() -> new UserNotFoundException("User not found with given email"));
+
+        log.info("Login attempt for user {}", passwordEncoder.encode(userToLogin.getEncryptedPassword()) + " " + userEntity.getEncryptedPassword());
+
         var loginSuccessful = passwordEncoder.matches(userToLogin.getEncryptedPassword(), userEntity.getEncryptedPassword());
         if (!loginSuccessful) {
             throw new InvalidCredentialsException("Invalid credentials");
         }
 
-        return "";
+        return jwtService.generateToken(userToLogin);
     }
 }

src/main/java/auth_service/domain/user/controller/UserController.java

@@ -0,0 +1,38 @@
+package auth_service.domain.user.controller;
+
+import io.micrometer.core.annotation.Timed;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.security.Principal;
+
+/**
+ * Controller handling user profile operations for the dashboard.
+ */
+@RestController
+@RequestMapping("/api/users")
+public class UserController {
+
+    /**
+     * Version 1 of the 'me' endpoint, accessed via /api/users/me?v=1
+     * * @return The user's dashboard data
+     */
+    @GetMapping(value = "/me", version = "1.0", produces = "application/json")
+    @Timed(value = "user.me.v1.requests.time", description = "Time taken to process v1 user profile requests")
+    public ResponseEntity<UserProfileResponse> getCurrentUserV1(Principal principal) {
+
+        // principal.getName() enthält die E-Mail, die der Türsteher aus dem Token gelesen hat!
+        String authenticatedEmail = principal.getName();
+
+        return ResponseEntity.ok(new UserProfileResponse(
+                authenticatedEmail,
+                "USER",
+                "Welcome to the v1 Dashboard, " + authenticatedEmail + "!"
+        ));
+    }
+
+    public record UserProfileResponse(String email, String role, String dashboardMessage) {
+    }
+}

src/main/resources/application-dev.yaml

@@ -11,4 +11,8 @@ app:
 # Optional: Make SQL logs visible for debugging
 spring:
   jpa:
-    show-sql: true
+    show-sql: true
+
+security:
+  jwt:
+    secret: "NzC9tQP1eTp496SxoVYslH1bqn81Tbfz74NjkFqdcVe7wayjcRN8IeZvJWd1s6NEWgwEXe9rdccvOn2HtJ4fdq"

src/main/resources/application.yaml

@@ -13,6 +13,13 @@ spring:
     baseline-on-migrate: true
     # Explicitly state where to look for scripts
     locations: classpath:db/migration
+  mvc:
+    apiversion:
+      use:
+        query-parameter: version
+      default: "1.0"
+      supported: 1.0, 2,0
+
 
 # Actuator & Micrometer Settings
 management:
@@ -29,6 +36,11 @@ management:
       export:
         enabled: true
 
+# Security stuff
+security:
+  jwt:
+    secret: ${JWT_SECRET}
+
 # Custom properties for CORS
 app:
   cors:

src/main/resources/db/migration/V1__init_schema.sql

@@ -10,4 +10,4 @@ CREATE TABLE users
 -- Insert a pragmatic test user for local development and testing
 -- The password hash corresponds to 'password123'
 INSERT INTO users (email, password, enabled)
-VALUES ('test@example.com', '$2a$10$8.UnVuG9HHgffUDAlk8qfOuVGkqRzgVymGe07xd00dmOn.jptTVyG', true);
+VALUES ('test@example.com', '$2a$10$3FApyf15qVEvFLEvl/d7aecSMZlslQdXiYlDgbOa4DfGWu4l0VCY.', true);