feat: add JWT authentication primitives

src/main/java/com/slotline/security/AuthenticatedUser.java

@@ -0,0 +1,6 @@
+package com.slotline.security;
+
+import com.slotline.user.Role;
+
+public record AuthenticatedUser(Long id, String username, Role role, Long organizationId) {
+}

src/main/java/com/slotline/security/JwtAuthenticationFilter.java

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+package com.slotline.security;
+
+import io.jsonwebtoken.JwtException;
+import jakarta.servlet.FilterChain;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.springframework.http.HttpHeaders;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+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.List;
+
+@Component
+public class JwtAuthenticationFilter extends OncePerRequestFilter {
+
+    private static final String BEARER_PREFIX = "Bearer ";
+
+    private final JwtService jwtService;
+
+    public JwtAuthenticationFilter(JwtService jwtService) {
+        this.jwtService = jwtService;
+    }
+
+    @Override
+    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
+            throws ServletException, IOException {
+        String header = request.getHeader(HttpHeaders.AUTHORIZATION);
+        boolean bearer = header != null && header.startsWith(BEARER_PREFIX);
+        if (bearer && SecurityContextHolder.getContext().getAuthentication() == null) {
+            try {
+                AuthenticatedUser principal = jwtService.parse(header.substring(BEARER_PREFIX.length()));
+                List<SimpleGrantedAuthority> authorities =
+                        List.of(new SimpleGrantedAuthority("ROLE_" + principal.role().name()));
+                UsernamePasswordAuthenticationToken authentication =
+                        new UsernamePasswordAuthenticationToken(principal, null, authorities);
+                authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
+                SecurityContextHolder.getContext().setAuthentication(authentication);
+            } catch (JwtException invalidToken) {
+                SecurityContextHolder.clearContext();
+            }
+        }
+        chain.doFilter(request, response);
+    }
+}

src/main/java/com/slotline/security/JwtService.java

@@ -0,0 +1,55 @@
+package com.slotline.security;
+
+import com.slotline.config.SlotlineProperties;
+import com.slotline.user.Role;
+import io.jsonwebtoken.Claims;
+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.time.Duration;
+import java.time.Instant;
+import java.util.Date;
+
+@Service
+public class JwtService {
+
+    private final SecretKey signingKey;
+    private final Duration expiration;
+    private final String issuer;
+
+    public JwtService(SlotlineProperties properties) {
+        this.signingKey = Keys.hmacShaKeyFor(properties.getJwt().getSecret().getBytes(StandardCharsets.UTF_8));
+        this.expiration = properties.getJwt().getExpiration();
+        this.issuer = properties.getJwt().getIssuer();
+    }
+
+    public String issue(Long userId, String username, Role role, Long organizationId) {
+        Instant now = Instant.now();
+        return Jwts.builder()
+                .issuer(issuer)
+                .subject(username)
+                .claim("uid", userId)
+                .claim("role", role.name())
+                .claim("org", organizationId)
+                .issuedAt(Date.from(now))
+                .expiration(Date.from(now.plus(expiration)))
+                .signWith(signingKey)
+                .compact();
+    }
+
+    public AuthenticatedUser parse(String token) {
+        Claims claims = Jwts.parser()
+                .verifyWith(signingKey)
+                .requireIssuer(issuer)
+                .build()
+                .parseSignedClaims(token)
+                .getPayload();
+        Long userId = ((Number) claims.get("uid")).longValue();
+        Role role = Role.valueOf(claims.get("role", String.class));
+        Long organizationId = ((Number) claims.get("org")).longValue();
+        return new AuthenticatedUser(userId, claims.getSubject(), role, organizationId);
+    }
+}

src/main/java/com/slotline/security/RestAuthenticationHandlers.java

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+package com.slotline.security;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import jakarta.servlet.http.HttpServletResponse;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ProblemDetail;
+import org.springframework.security.web.AuthenticationEntryPoint;
+import org.springframework.security.web.access.AccessDeniedHandler;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+@Component
+public class RestAuthenticationHandlers {
+
+    private final ObjectMapper objectMapper;
+
+    public RestAuthenticationHandlers(ObjectMapper objectMapper) {
+        this.objectMapper = objectMapper;
+    }
+
+    public AuthenticationEntryPoint authenticationEntryPoint() {
+        return (request, response, exception) ->
+                write(response, HttpStatus.UNAUTHORIZED, "Authentication required", request.getRequestURI());
+    }
+
+    public AccessDeniedHandler accessDeniedHandler() {
+        return (request, response, exception) ->
+                write(response, HttpStatus.FORBIDDEN, "Access denied", request.getRequestURI());
+    }
+
+    private void write(HttpServletResponse response, HttpStatus status, String detail, String path) throws IOException {
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(status, detail);
+        problem.setTitle(status.getReasonPhrase());
+        problem.setProperty("path", path);
+        response.setStatus(status.value());
+        response.setContentType(MediaType.APPLICATION_PROBLEM_JSON_VALUE);
+        objectMapper.writeValue(response.getOutputStream(), problem);
+    }
+}