feat: oauth 로그인 구현

src/main/java/com/example/oauthspringsecurity/domain/OAuthAttributes.java

@@ -0,0 +1,49 @@
+package com.example.oauthspringsecurity.domain;
+
+import java.util.Arrays;
+import java.util.Map;
+import java.util.function.Function;
+
+public enum OAuthAttributes {
+    GITHUB("github", (attributes) -> {
+        return new UserProfile(
+                String.valueOf(attributes.get("id")),
+                (String) attributes.get("name"),
+                (String) attributes.get("email"),
+                (String) attributes.get("avatar_url")
+        );
+    }),
+    GOOGLE("google", (attributes) -> {
+        return new UserProfile(
+                String.valueOf(attributes.get("sub")),
+                (String) attributes.get("name"),
+                (String) attributes.get("email"),
+                (String) attributes.get("picture")
+        );
+    }),
+    NAVER("naver", (attributes) -> {
+        Map<String, Object> response = (Map<String, Object>) attributes.get("response");
+        return new UserProfile(
+                (String) response.get("id"),
+                (String) response.get("name"),
+                (String) response.get("email"),
+                (String) response.get("profile_image")
+        );
+    });
+
+    private final String registrationId;
+    private final Function<Map<String, Object>, UserProfile> of;
+
+    OAuthAttributes(String registrationId, Function<Map<String, Object>, UserProfile> of) {
+        this.registrationId = registrationId;
+        this.of = of;
+    }
+
+    public static UserProfile extract(String registrationId, Map<String, Object> attributes) {
+        return Arrays.stream(values())
+                     .filter(provider -> registrationId.equals(provider.registrationId))
+                     .findFirst()
+                     .orElseThrow(IllegalArgumentException::new)
+                .of.apply(attributes);
+    }
+}

src/main/java/com/example/oauthspringsecurity/domain/UserProfile.java

@@ -0,0 +1,35 @@
+package com.example.oauthspringsecurity.domain;
+
+public class UserProfile {
+    private final String oauthId;
+    private final String name;
+    private final String email;
+    private final String imageUrl;
+
+    public UserProfile(String oauthId, String name, String email, String imageUrl) {
+        this.oauthId = oauthId;
+        this.name = name;
+        this.email = email;
+        this.imageUrl = imageUrl;
+    }
+
+    public Member toMember() {
+        return new Member(oauthId, name, email, imageUrl, Role.USER);
+    }
+
+    public String getOauthId() {
+        return oauthId;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public String getImageUrl() {
+        return imageUrl;
+    }
+}

src/main/java/com/example/oauthspringsecurity/repository/MemberRepository.java

@@ -0,0 +1,11 @@
+package com.example.oauthspringsecurity.repository;
+
+import java.util.Optional;
+
+import com.example.oauthspringsecurity.domain.Member;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface MemberRepository extends JpaRepository<Member, Long> {
+    Optional<Member> findByOauthId(String id);
+}

src/main/java/com/example/oauthspringsecurity/service/OAuthService.java

@@ -1,15 +1,55 @@
 package com.example.oauthspringsecurity.service;
 
+import java.util.Collections;
+import java.util.Map;
+
+import com.example.oauthspringsecurity.domain.Member;
+import com.example.oauthspringsecurity.domain.OAuthAttributes;
+import com.example.oauthspringsecurity.domain.UserProfile;
+import com.example.oauthspringsecurity.repository.MemberRepository;
+
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.oauth2.client.userinfo.DefaultOAuth2UserService;
 import org.springframework.security.oauth2.client.userinfo.OAuth2UserRequest;
 import org.springframework.security.oauth2.client.userinfo.OAuth2UserService;
 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;
 
 @Service
 public class OAuthService implements OAuth2UserService<OAuth2UserRequest, OAuth2User> {
+    private final MemberRepository memberRepository;
+
+    public OAuthService(MemberRepository memberRepository) {
+        this.memberRepository = memberRepository;
+    }
+
     @Override
     public OAuth2User loadUser(OAuth2UserRequest userRequest) throws OAuth2AuthenticationException {
-        return null;
+        OAuth2UserService delegate = new DefaultOAuth2UserService();
+        OAuth2User oAuth2User = delegate.loadUser(userRequest); // OAuth 서비스(github, google, naver)에서 가져온 유저 정보를 담고있음
+
+        String registrationId = userRequest.getClientRegistration()
+                                           .getRegistrationId(); // OAuth 서비스 이름(github, naver, google)
+        String userNameAttributeName = userRequest.getClientRegistration().getProviderDetails()
+                                                  .getUserInfoEndpoint().getUserNameAttributeName();
+        Map<String, Object> attributes = oAuth2User.getAttributes();
+
+        UserProfile userProfile = OAuthAttributes.extract(registrationId, attributes);
+
+        Member member = saveOrUpdate(userProfile);
+
+        return new DefaultOAuth2User(
+                Collections.singleton(new SimpleGrantedAuthority(member.getRoleKey())),
+                attributes,
+                userNameAttributeName);
+    }
+
+    private Member saveOrUpdate(UserProfile userProfile) {
+        Member member = memberRepository.findByOauthId(userProfile.getOauthId())
+                                        .map(m -> m.update(userProfile.getName(), userProfile.getEmail(), userProfile.getImageUrl()))
+                                        .orElse(userProfile.toMember());
+        return memberRepository.save(member);
     }
 }