✨practice(#10) : OAuth2를 활용한 카카오 소셜 로그인 구현

spring/build.gradle

@@ -42,6 +42,9 @@ dependencies {
 	implementation 'org.springframework.boot:spring-boot-starter-security'
 	testImplementation 'org.springframework.security:spring-security-test'
 
+	// Spring Security OAuth2 클라이언트 의존성 추가
+	implementation 'org.springframework.boot:spring-boot-starter-oauth2-client'
+
 	//Thymeleaf
 	implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
 	implementation 'org.thymeleaf.extras:thymeleaf-extras-springsecurity6:3.1.1.RELEASE'

spring/src/main/java/umc/spring/config/security/CustomOAuth2UserService.java

@@ -0,0 +1,65 @@
+package umc.spring.config.security;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.oauth2.client.userinfo.DefaultOAuth2UserService;
+import org.springframework.security.oauth2.client.userinfo.OAuth2UserRequest;
+import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
+import org.springframework.security.oauth2.core.user.DefaultOAuth2User;
+import org.springframework.security.oauth2.core.user.OAuth2User;
+import org.springframework.stereotype.Service;
+import umc.spring.domain.Member;
+import umc.spring.domain.enums.Gender;
+import umc.spring.domain.enums.Role;
+import umc.spring.repository.MemberRepository.MemberRepository;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+
+@Service
+@RequiredArgsConstructor
+public class CustomOAuth2UserService extends DefaultOAuth2UserService {
+
+    private final MemberRepository memberRepository;
+    private final PasswordEncoder passwordEncoder;
+
+    @Override
+    public OAuth2User loadUser(OAuth2UserRequest userRequest) throws OAuth2AuthenticationException {
+        OAuth2User oAuth2User = super.loadUser(userRequest);
+
+        Map<String, Object> attributes = oAuth2User.getAttributes();
+        Map<String, Object> properties = (Map<String, Object>) attributes.get("properties");
+
+        String nickname = (String) properties.get("nickname");
+        String email = nickname + "@kakao.com"; // 임시 이메일 생성
+
+        // 사용자 정보 저장 또는 업데이트
+        Member member = saveOrUpdateUser(email, nickname);
+
+        // 이메일을 Principal로 사용하기 위해 attributes 수정
+        Map<String, Object> modifiedAttributes = new HashMap<>(attributes);
+        modifiedAttributes.put("email", email);
+
+        return new DefaultOAuth2User(
+                oAuth2User.getAuthorities(),
+                modifiedAttributes,
+                "email"  // email Principal로 설정
+        );
+    }
+
+    private Member saveOrUpdateUser(String email, String nickname) {
+        Member member = memberRepository.findByEmail(email)
+                .orElse(Member.builder()
+                        .email(email)
+                        .name(nickname)
+                        .password(passwordEncoder.encode("OAUTH_USER_" + UUID.randomUUID()))
+                        .gender(Gender.NONE)  // 기본값 설정
+                        .address("소셜로그인")  // 기본값 설정
+                        .specAddress("소셜로그인")  // 기본값 설정
+                        .role(Role.USER)
+                        .build());
+
+        return memberRepository.save(member);
+    }
+}

spring/src/main/java/umc/spring/config/security/SecurityConfig.java

@@ -25,6 +25,11 @@ public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Excepti
                         .defaultSuccessUrl("/home", true)
                         .permitAll()
                 )
+                .oauth2Login(oauth2 -> oauth2
+                        .loginPage("/login")
+                        .defaultSuccessUrl("/home", true)
+                        .permitAll()
+                )
                 .logout((logout) -> logout
                         .logoutUrl("/logout")
                         .logoutSuccessUrl("/login?logout")

spring/src/main/resources/application.yml

@@ -16,4 +16,22 @@ spring:
         use_sql_comments: true
         hbm2ddl:
           auto: update
-        default_batch_fetch_size: 1000
+        default_batch_fetch_size: 1000
+  security:
+    oauth2:
+      client:
+        registration:
+          kakao:
+            client-authentication-method: client_secret_post
+            client-id: b520cf6225bb08837856b4bcee2232be
+            client-secret: 5lBI2OF2hvUBAUHbG2QSUuFeyDCGb6Yn
+            redirect-uri: http://localhost:8080/login/oauth2/code/kakao
+            authorization-grant-type: authorization_code
+            scope: profile_nickname
+            client-name: Kakao
+        provider:
+          kakao:
+            authorization-uri: https://kauth.kakao.com/oauth/authorize
+            token-uri: https://kauth.kakao.com/oauth/token
+            user-info-uri: https://kapi.kakao.com/v2/user/me
+            user-name-attribute: id

spring/src/main/resources/templates/login.html

@@ -20,5 +20,6 @@ <h2>Login</h2>
 <p th:if="${param.logout}">로그아웃되었습니다.</p>
 <!-- 회원가입 링크 수정 -->
 <p>계정이 없나요? <a th:href="@{/signup}">Sign up</a></p>
+<a th:href="@{/oauth2/authorization/kakao}">카카오로 로그인</a>
 </body>
 </html>