SPRING JWT 구현

목표

@Controller 페이지를 개설 후 JWT 토큰이 발급된 사용자만이 접근할 수 있도록
기능을 구성하여 접근 권한 관리하도록 한다.

구현

1. 멤버등록(회원가입) 구현

웹페이지 접근 이전에 사용자가 가입된 상태인지 확인하도록 한다.

구현은 CRUD 구현괴 유사하지만 보한 특성을 강화하기 위해 Password는 PasswordEncoder.encode 메소드를 통해 함수화 한다.

@RestController
@RequiredArgsConstructor
public class MemberController {

    final MemberRepository memberRepository;
    final PasswordEncoder encode;

    @PostMapping("/api/member")
    public String saveMember(@RequestBody MemberDto memberDto) {
        memberRepository.save(Member.createMember(memberDto.getEmail(), encode.encode(memberDto.getPassword())));
        return "success";
    }

}

@Data
class MemberDto {
    private String email;
    private String password;
}

• Request

  POST : http://localhost:8080/api/member

  {
    "email" : "user",
    "password" : "user"
  }

• Response

  {
    "timestamp": "2021-07-02T15:36:46.098+0000",
    "status": 401,
    "error": "Unauthorized",
    "message": "UnAuthorized",
    "path": "/hello"
  }

---

2. JWT 토큰 발급

웹 관점에서 본다면 등록된 사용자가 로그인할 경우 토큰을 부여하여 토큰 유효시간 동안 추가 로그인 없이 서비스를 이용할 수 있도록
구성하야한다. 웹을 빠져나가도 토큰 유효시간 동안 사용자는 로그인 상태를 유지하고 있어 해당 페이지에 재접속해도 사용자 정보를 유지할 수 있게 된다.

@RestController
@CrossOrigin
public class JwtAuthenticationController {

    @Autowired
    private JwtTokenUtil jwtTokenUtil;

    @Autowired
    private JwtUserDetailsService userDetailService;

    @PostMapping("/authenticate")
    public ResponseEntity<?> createAuthenticationToken(@RequestBody JwtRequest authenticationRequest) throws Exception {
        final Member member = userDetailService.authenticateByEmailAndPassword
                (authenticationRequest.getEmail(), authenticationRequest.getPassword());
        final String token = jwtTokenUtil.generateToken(member.getEmail());
        return ResponseEntity.ok(new JwtResponse(token));
    }

}

@Data
class JwtRequest {

    private String email;
    private String password;

}

@Data
@AllArgsConstructor
class JwtResponse {

    private String token;

}

@Component
public class JwtTokenUtil {

    private static final String secret = "jwtpassword";

    // 토큰 유효시간
    public static final long JWT_TOKEN_VALIDITY = 5 * 60 * 60;

    public String getUsernameFromToken(String token) {
        return getClaimFromToken(token, Claims::getId);
    }

    public <T> T getClaimFromToken(String token, Function<Claims, T> claimsResolver) {
        final Claims claims = getAllClaimsFromToken(token);
        return claimsResolver.apply(claims);
    }

    private Claims getAllClaimsFromToken(String token) {
        return Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody();
    }

    private Boolean isTokenExpired(String token) {
        final Date expiration = getExpirationDateFromToken(token);
        return expiration.before(new Date());
    }

    public Date getExpirationDateFromToken(String token) {
        return getClaimFromToken(token, Claims::getExpiration);
    }

    public String generateToken(String id) {
        return generateToken(id, new HashMap<>());
    }

    public String generateToken(String id, Map<String, Object> claims) {
        return doGenerateToken(id, claims);
    }

    // 암호 구현의 만료시간, 암호화 방식을 설정하고 반환
    private String doGenerateToken(String id, Map<String, Object> claims) {
        return Jwts.builder()
                .setClaims(claims)
                .setId(id)
                .setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(new Date(System.currentTimeMillis() + JWT_TOKEN_VALIDITY * 1000))
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }

    public Boolean validateToken(String token, UserDetails userDetails) {
        final String username = getUsernameFromToken(token);
        return (username.equals(userDetails.getUsername())) && !isTokenExpired(token);
    }

}

@Service
public class JwtUserDetailsService implements UserDetailsService {

    @Autowired
    private PasswordEncoder passwordEncoder;

    @Bean
    public BCryptPasswordEncoder passwordEncoder() {
        BCryptPasswordEncoder bCryptPasswordEncoder = new BCryptPasswordEncoder();
        return bCryptPasswordEncoder;
    }

    @Autowired
    private MemberRepository memberRepository;

    @Override
    public UserDetails loadUserByUsername(String email) throws UsernameNotFoundException {
        Member member = memberRepository.findByEmail(email)
                .orElseThrow(() -> new UsernameNotFoundException(email));
        Set<GrantedAuthority> grantedAuthorities = new HashSet<>();
        grantedAuthorities.add(new SimpleGrantedAuthority(Role.USER.getValue()));
        if (email.equals("whatever you want a email")) {
            grantedAuthorities.add(new SimpleGrantedAuthority(Role.ADMIN.getValue()));
        }

        return new User(member.getEmail(), member.getPassword(), grantedAuthorities);
    }

    public Member authenticateByEmailAndPassword(String email, String password) {
        Member member = memberRepository.findByEmail(email)
                .orElseThrow(() -> new UsernameNotFoundException(email));

        if(!passwordEncoder.matches(password, member.getPassword())) {
            throw new BadCredentialsException("Password not matched");
        }

        return member;
    }

}

1. @RequestBody 에서 데이터(email, password)를 가져온다.
2. 데이터(email, password)를 확인한여 등록된 사용자인지 확인한다.
3. 데이터를 DB에서 조회후 등록된 사용자라면 구현한 jwtTokenUtil.generateToken 메소드를 통해 토큰을 생성하여 반환한다.

---

3. Authorized Check

토큰은 헤더에 포함되어 서버에 전송되게 되는데 Authorized 에 해당하는 Bearer "your Token" 의 형태로 전송되게 된다.
서버에서는 토큰은 유효성을 분석하여 상태를 반환하고 유효한 토큰일 경우에는 jwtTokenUtil.validateToken 메소드를 통해 페이지 http에 대한 request / response를
반환한다.

Bearer ??

Authentication API의 인증 방법중 하나이며 RFC 6750에 표준명세서에 따라 고안된 인증 방식이다.

사용법

GET /resource HTTP/1.1 Host: server.example.com Authorization: Bearer mF_9.B5f-4.1JqM

@Component
public class JwtRequestFilter extends OncePerRequestFilter {

    @Autowired
    private JwtUserDetailsService jwtUserDetailService;

    @Autowired
    private JwtTokenUtil jwtTokenUtil;

    private static final List<String> EXCLUDE_URL =
            Collections.unmodifiableList(
                    Arrays.asList(
                        "/api/member",
                        "/authenticate"
                    ));

    @Override
    protected void doFilterInternal(HttpServletRequest request,
                                    HttpServletResponse response,
                                    FilterChain filterChain) throws ServletException, IOException {

        final String requestTokenHeader = request.getHeader("Authorization");

        String username = null;
        String jwtToken = null;

        if (requestTokenHeader != null && requestTokenHeader.startsWith("Bearer ")) {
            jwtToken = requestTokenHeader.substring(7);
            try {
                username = jwtTokenUtil.getUsernameFromToken(jwtToken);
            } catch (IllegalArgumentException e) {
                System.out.println("Unable to get JWT Token");
            } catch (ExpiredJwtException e) {
                System.out.println("JWT Token has expired");
            }
        } else {
            logger.warn("JWT Token does not begin with Bearer String");
        }

        if(username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
            UserDetails userDetails = this.jwtUserDetailService.loadUserByUsername(username);

            if(jwtTokenUtil.validateToken(jwtToken, userDetails)) {
                UsernamePasswordAuthenticationToken authenticationToken =
                        new UsernamePasswordAuthenticationToken(userDetails, null ,userDetails.getAuthorities());

                authenticationToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
                SecurityContextHolder.getContext().setAuthentication(authenticationToken);
            }
        }
        filterChain.doFilter(request,response);
    }

    @Override
    protected boolean shouldNotFilter(HttpServletRequest request) throws ServletException {
        return EXCLUDE_URL.stream().anyMatch(exclude -> exclude.equalsIgnoreCase(request.getServletPath()));
    }

}

• Request

  POST : http://localhost:8080/authenticate

  {
    "email" : "user",
    "password" : "user"
  }

• Response(성공 / 실패)

  {
  "token": "eyJhbGciOiJIUzUxMiJ9.eyJleHAiOjE2MjUyNjMyNDksImlhdCI6MTYyNTI0NTI0OSwianRpIjoic3VwMmlzQGdtYWlsLmNvbSJ9.aC_kRlQrSDALt2gtwl2AXRWJRPMkGERDmvWRsAYZlx0FFBb_UGurlHSYPf7Z7RS_BvAn_mq9rgd6GHBi7UXIpA"
  }

{
  "timestamp": "2021-07-02T17:05:10.510+0000",
  "status": 401,
  "error": "Unauthorized",
  "message": "UnAuthorized",
  "path": "/authenticate"
}

---

4. UnAuthorized 처리

1. WebSecurityConfig를 구현하여 개발자가 원하는 웹 보안 수준을 설정한다.

@Configuration
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private AuthenticationEntryPoint jwtAuthenticationEntryPoint;

    @Autowired
    private UserDetailsService jwtUserDetailsService;

    @Autowired
    private JwtRequestFilter jwtRequestFilter;

    @Autowired
    private DataSource dataSource;

    @Autowired
    private PasswordEncoder passwordEncoder;

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {

        auth.jdbcAuthentication().dataSource(dataSource);
        auth
                .userDetailsService(jwtUserDetailsService)
                .passwordEncoder(passwordEncoder);
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
                .csrf().disable()
                .authorizeRequests().antMatchers("/authenticate", "/api/member").permitAll()
                .anyRequest().authenticated()
                .and()
                .exceptionHandling()
                .authenticationEntryPoint(jwtAuthenticationEntryPoint)
                .and()
                .sessionManagement()
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS);

        http.addFilterBefore(jwtRequestFilter, UsernamePasswordAuthenticationFilter.class);
    }
}

@Component
public class JwtAuthenticationEntryPoint implements AuthenticationEntryPoint {

    @Override
    public void commence(HttpServletRequest request,
                         HttpServletResponse response,
                         AuthenticationException e) throws IOException, ServletException {

        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "UnAuthorized");
    }

}

인증이 실패한 사용자일 경우 Web에서 "UnAuthorized"를 반환 한다.

{
    "timestamp": "2021-07-02T17:05:10.510+0000",
    "status": 401,
    "error": "Unauthorized",
    "message": "UnAuthorized",
    "path": "/authenticate"
}

---

접속

인가된 사용자가 접속하여 TOKEN은 가지고 있는 상태라면 원하는 페이지에 접속을 허가해야한다.

• Request

  GET : http://localhost:8080/hello

• Return

  Hello World

Gradle Setting

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.7.0'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.7.0'
    implementation 'io.jsonwebtoken:jjwt:0.9.1'

    implementation 'org.springframework.boot:spring-boot-starter-web'
    compile('com.h2database:h2')

    compile("org.springframework.boot:spring-boot-starter-data-jpa")
    compileOnly 'org.projectlombok:lombok'
    annotationProcessor 'org.projectlombok:lombok'
    testCompile('org.springframework.boot:spring-boot-starter-test')

    implementation 'org.springframework.boot:spring-boot-starter-security'
}

MyCode

JWT Token Repo

🧾Reference

1. JSON 웹 토큰
2. JWT 구조
3. spring-boot JWT 예제
4. Bearer Authentication