feat: Google OAuth 로그인/회원가입 구현

build.gradle

@@ -27,6 +27,7 @@ dependencies {
 	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
 	implementation 'org.springframework.boot:spring-boot-starter-security'
 	implementation 'org.springframework.boot:spring-boot-starter-web'
+	implementation 'org.springframework.boot:spring-boot-starter-oauth2-client'
 	implementation 'org.springdoc:springdoc-openapi-starter-webmvc-ui:2.2.0'
 	compileOnly 'org.projectlombok:lombok'
 	runtimeOnly 'com.h2database:h2'

src/main/java/com/j9/bestmoments/auth/AuthController.java

@@ -0,0 +1,36 @@
+package com.j9.bestmoments.auth;
+
+import com.j9.bestmoments.auth.oauth.dto.request.OAuthUserInfoDto;
+import com.j9.bestmoments.auth.oauth.service.GoogleAuthService;
+import com.j9.bestmoments.auth.oauth.service.OAuthService;
+import io.swagger.v3.oas.annotations.Operation;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("auth")
+@RequiredArgsConstructor
+@Slf4j
+public class AuthController {
+
+    private final GoogleAuthService googleAuthService;
+
+    @GetMapping("/login/{oAuthProvider}")
+    @Operation(summary = "OAuth 인증코드로 로그인/회원가입", description = "oAuthProvider: google")
+    public String login(@PathVariable String oAuthProvider, @RequestParam String code) {
+        OAuthService oAuthService = switch (oAuthProvider) {
+            case "google" -> googleAuthService;
+            default -> throw new OAuth2AuthenticationException("존재하지 않는 OAuth 인증 방식입니다.");
+        };
+        OAuthUserInfoDto oAuthUserInfo = oAuthService.getUserInfo(code);
+        log.info(oAuthUserInfo.toString());
+        return "토큰 발급";
+    }
+
+}

src/main/java/com/j9/bestmoments/auth/oauth/dto/request/OAuthUserInfoDto.java

@@ -0,0 +1,14 @@
+package com.j9.bestmoments.auth.oauth.dto.request;
+
+import lombok.Builder;
+
+@Builder
+public record OAuthUserInfoDto(
+        String provider,
+        String id,
+        String name,
+        String email,
+        String profileImageUrl
+) {
+
+}

src/main/java/com/j9/bestmoments/auth/oauth/service/GoogleAuthService.java

@@ -0,0 +1,77 @@
+package com.j9.bestmoments.auth.oauth.service;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.j9.bestmoments.auth.oauth.dto.request.OAuthUserInfoDto;
+import java.util.Collections;
+import java.util.Map;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Service;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RestTemplate;
+
+@Service
+public class GoogleAuthService implements OAuthService {
+
+    @Value("${spring.security.oauth2.client.registration.google.client-id}")
+    private String clientId;
+
+    @Value("${spring.security.oauth2.client.registration.google.client-secret}")
+    private String clientSecret;
+
+    @Value("${spring.security.oauth2.client.registration.google.redirect-uri}")
+    private String redirectUri;
+
+    @Value("${spring.security.oauth2.client.registration.google.token-uri}")
+    private String tokenUri;
+
+    @Value("${spring.security.oauth2.client.registration.google.userinfo-uri}")
+    private String userinfoUrl;
+
+    @Override
+    public OAuthUserInfoDto getUserInfo(String code) {
+        String accessToken = getAccessToken(code);
+        Map attributes = getUserInfoAttributes(accessToken);
+        return OAuthUserInfoDto.builder()
+                .provider("google")
+                .id(attributes.get("id").toString())
+                .name(attributes.get("name").toString())
+                .email(attributes.get("email").toString())
+                .profileImageUrl(attributes.get("picture").toString())
+                .build();
+    }
+
+    private String getAccessToken(String code) {
+        MultiValueMap<String, String> params = new LinkedMultiValueMap<>();
+        params.put("code", Collections.singletonList(code));
+        params.put("client_id", Collections.singletonList(clientId));
+        params.put("client_secret", Collections.singletonList(clientSecret));
+        params.put("redirect_uri", Collections.singletonList(redirectUri));
+        params.put("grant_type", Collections.singletonList("authorization_code"));
+
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
+
+        HttpEntity entity = new HttpEntity(params, headers);
+
+        RestTemplate restTemplate = new RestTemplate();
+        ResponseEntity<JsonNode> responseNode = restTemplate.exchange(tokenUri, HttpMethod.POST, entity, JsonNode.class);
+        JsonNode accessTokenNode = responseNode.getBody();
+
+        return accessTokenNode.get("access_token").asText();
+    }
+
+    private Map getUserInfoAttributes(String accessToken) {
+        HttpHeaders headers = new HttpHeaders();
+        headers.setBearerAuth(accessToken);
+        HttpEntity<String> entity = new HttpEntity<>(headers);
+        RestTemplate restTemplate = new RestTemplate();
+        return restTemplate.exchange(userinfoUrl, HttpMethod.GET, entity, Map.class).getBody();
+    }
+
+}

src/main/java/com/j9/bestmoments/auth/oauth/service/OAuthService.java

@@ -0,0 +1,9 @@
+package com.j9.bestmoments.auth.oauth.service;
+
+import com.j9.bestmoments.auth.oauth.dto.request.OAuthUserInfoDto;
+
+public interface OAuthService {
+
+    OAuthUserInfoDto getUserInfo(String code);
+
+}

src/main/java/com/j9/bestmoments/member/MemberRepository.java

@@ -0,0 +1,12 @@
+package com.j9.bestmoments.member;
+
+import java.util.Optional;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface MemberRepository extends JpaRepository<Member, String> {
+
+    Optional<Member> findByOauthProviderAndOauthId(String oauthProvider, String oauthId);
+
+}

src/main/java/com/j9/bestmoments/member/MemberService.java

@@ -0,0 +1,34 @@
+package com.j9.bestmoments.member;
+
+import com.j9.bestmoments.auth.oauth.dto.request.OAuthUserInfoDto;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+public class MemberService {
+
+    private final MemberRepository memberRepository;
+
+    @Transactional
+    public Member findOrSaveByOAuthInfo(OAuthUserInfoDto oAuth2UserInfo) {
+        Member member = memberRepository.findByOauthProviderAndOauthId(oAuth2UserInfo.provider(), oAuth2UserInfo.id())
+                .orElse(this.create(oAuth2UserInfo));
+        return memberRepository.save(member);
+    }
+
+    private Member create(OAuthUserInfoDto oAuthUserInfoDto) {
+        Member member = Member.builder()
+                .oauthId(oAuthUserInfoDto.id())
+                .oauthProvider(oAuthUserInfoDto.provider())
+                .name(oAuthUserInfoDto.name())
+                .email(oAuthUserInfoDto.email())
+                .profileImageUrl(oAuthUserInfoDto.profileImageUrl())
+                .role(MemberRole.USER)
+                .build();
+
+        return memberRepository.save(member);
+    }
+
+}