FEAT: 구글 소셜 로그인 구현

api/build.gradle

@@ -20,6 +20,8 @@ dependencies {
     implementation 'io.jsonwebtoken:jjwt-impl:0.12.6'
     implementation 'io.jsonwebtoken:jjwt-jackson:0.12.6'
 
+    implementation 'org.springframework.boot:spring-boot-starter-webflux'
+
     runtimeOnly 'com.mysql:mysql-connector-j'
     runtimeOnly 'com.h2database:h2'
 

api/src/main/java/com/pinback/api/config/filter/JwtAuthenticationFilter.java

@@ -96,7 +96,11 @@ protected boolean shouldNotFilter(HttpServletRequest request) throws ServletExce
 				path.startsWith("/v3/api-docs") ||
 				path.startsWith("/docs") ||
 				path.startsWith("/api/v1/test/push") ||
-				path.startsWith("/api/v1/test/health")
+				path.startsWith("/api/v1/test/health") ||
+				path.startsWith("/api/v1/auth/google") ||
+				path.startsWith("/oauth/callback") ||
+				path.startsWith("/login/google") ||
+				path.startsWith("/login/oauth2/code/google")
 			;
 	}
 }

api/src/main/java/com/pinback/api/config/security/SecurityConfig.java

@@ -52,13 +52,20 @@ public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
 				).permitAll()
 
 				.requestMatchers(
-					"/api/v1/auth/token"
+					"/api/v1/auth/token",
+					"/api/v1/auth/google"
 				).permitAll()
 
 				.requestMatchers(
 					"/api/v1/test/*"
 				).permitAll()
 
+				.requestMatchers(
+					"/login/google",
+					"/oauth/callback",
+					"/login/oauth2/code/google"
+				).permitAll()
+
 				.anyRequest().authenticated()
 			)
 			.formLogin(AbstractHttpConfigurer::disable)

api/src/main/java/com/pinback/api/google/controller/GoogleLonginController.java

@@ -0,0 +1,44 @@
+package com.pinback.api.google.controller;
+
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.pinback.api.google.dto.request.GoogleLoginRequest;
+import com.pinback.application.auth.usecase.AuthUsecase;
+import com.pinback.application.google.dto.response.GoogleLoginResponse;
+import com.pinback.application.google.usecase.GoogleUsecase;
+import com.pinback.shared.dto.ResponseDto;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import reactor.core.publisher.Mono;
+
+@Slf4j
+@RestController
+@RequestMapping("/api/v1/auth/google")
+@RequiredArgsConstructor
+@Tag(name = "Google", description = "구글 소셜 로그인 API")
+public class GoogleLonginController {
+
+	private final GoogleUsecase googleUsecase;
+	private final AuthUsecase authUsecase;
+
+	@Operation(summary = "구글 소셜 로그인", description = "구글을 통한 소셜 로그인을 진행합니다")
+	@PostMapping()
+	public Mono<ResponseDto<GoogleLoginResponse>> googleLogin(
+		@Valid @RequestBody GoogleLoginRequest request
+	) {
+		return googleUsecase.getUserInfo(request.toCommand())
+			.flatMap(googleResponse -> {
+				return authUsecase.getInfoAndToken(googleResponse.email())
+					.map(loginResponse -> {
+						return ResponseDto.ok(loginResponse);
+					});
+			});
+	}
+}

api/src/main/java/com/pinback/api/google/dto/request/GoogleLoginRequest.java

@@ -0,0 +1,14 @@
+package com.pinback.api.google.dto.request;
+
+import com.pinback.application.google.dto.GoogleLoginCommand;
+
+import jakarta.validation.constraints.NotNull;
+
+public record GoogleLoginRequest(
+	@NotNull(message = "인가 코드(code)는 비어있을 수 없습니다.")
+	String code
+) {
+	public GoogleLoginCommand toCommand() {
+		return new GoogleLoginCommand(code);
+	}
+}

api/src/main/resources/application.yml

@@ -27,3 +27,10 @@ jwt:
   issuer: ${ISSUER}
 
 fcm: ${FCM_JSON}
+
+google:
+  client-id: ${CLIENT_ID}
+  client-secret: ${CLIENT_SECRET}
+  redirect-uri: ${REDIRECT_URI}
+  token-uri: ${TOKEN_URI}
+  user-info-uri: ${USER_INFO_URI}

application/build.gradle

@@ -4,13 +4,15 @@
 dependencies {
     // 도메인 모듈 (핵심 비즈니스 로직)
     api project(':domain')
-    
+
     // Spring Boot (애플리케이션 서비스를 위한 기본 스프링 기능)
     implementation 'org.springframework.boot:spring-boot-starter'
-    
+
     // 트랜잭션 관리와 페이징을 위한 JPA
     implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
-    
+
     // Test용 H2 데이터베이스
     testImplementation 'com.h2database:h2'
+
+    implementation 'org.springframework.boot:spring-boot-starter-webflux'
 }

application/src/main/java/com/pinback/application/auth/usecase/AuthUsecase.java

@@ -7,14 +7,18 @@
 import com.pinback.application.auth.dto.SignUpResponse;
 import com.pinback.application.auth.dto.TokenResponse;
 import com.pinback.application.auth.service.JwtProvider;
+import com.pinback.application.google.dto.response.GoogleLoginResponse;
 import com.pinback.application.notification.port.in.SavePushSubscriptionPort;
 import com.pinback.application.user.port.out.UserGetServicePort;
 import com.pinback.application.user.port.out.UserSaveServicePort;
 import com.pinback.application.user.port.out.UserValidateServicePort;
 import com.pinback.domain.user.entity.User;
 
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import reactor.core.publisher.Mono;
 
+@Slf4j
 @Service
 @RequiredArgsConstructor
 public class AuthUsecase {
@@ -46,4 +50,28 @@ public TokenResponse getToken(String email) {
 
 		return new TokenResponse(accessToken);
 	}
+
+	@Transactional(readOnly = true)
+	public Mono<GoogleLoginResponse> getInfoAndToken(String email) {
+		return userGetServicePort.findUserByEmail(email)
+			.flatMap(existingUser -> {
+				log.info("기존 사용자 로그인 성공: User ID {}", existingUser.getId());
+
+				//Access Token 발급
+				String accessToken = jwtProvider.createAccessToken(existingUser.getId());
+
+				return Mono.just(GoogleLoginResponse.loggedIn(
+					existingUser.getId(), existingUser.getEmail(), accessToken
+				));
+			})
+			.switchIfEmpty(Mono.defer(() -> {
+				log.info("신규 유저 - 임시 유저 생성");
+				User tempUser = User.createTempUser(email);
+
+				return userSaveServicePort.saveUser(tempUser)
+					.flatMap(savedUser -> {
+						return Mono.just(GoogleLoginResponse.tempLogin(savedUser.getId(), savedUser.getEmail()));
+					});
+			}));
+	}
 }

application/src/main/java/com/pinback/application/common/exception/GoogleApiException.java

@@ -0,0 +1,10 @@
+package com.pinback.application.common.exception;
+
+import com.pinback.shared.constant.ExceptionCode;
+import com.pinback.shared.exception.ApplicationException;
+
+public class GoogleApiException extends ApplicationException {
+	public GoogleApiException() {
+		super(ExceptionCode.GOOGLE_API_ERROR);
+	}
+}

application/src/main/java/com/pinback/application/common/exception/GoogleEmailMissingException.java

@@ -0,0 +1,10 @@
+package com.pinback.application.common.exception;
+
+import com.pinback.shared.constant.ExceptionCode;
+import com.pinback.shared.exception.ApplicationException;
+
+public class GoogleEmailMissingException extends ApplicationException {
+	public GoogleEmailMissingException() {
+		super(ExceptionCode.GOOGLE_EMAIL_MISSING);
+	}
+}

application/src/main/java/com/pinback/application/common/exception/GoogleTokenMissingException.java

@@ -0,0 +1,10 @@
+package com.pinback.application.common.exception;
+
+import com.pinback.shared.constant.ExceptionCode;
+import com.pinback.shared.exception.ApplicationException;
+
+public class GoogleTokenMissingException extends ApplicationException {
+	public GoogleTokenMissingException() {
+		super(ExceptionCode.GOOGLE_TOKEN_MISSING);
+	}
+}

application/src/main/java/com/pinback/application/google/dto/GoogleLoginCommand.java

@@ -0,0 +1,6 @@
+package com.pinback.application.google.dto;
+
+public record GoogleLoginCommand(
+	String code
+) {
+}

application/src/main/java/com/pinback/application/google/dto/response/GoogleApiResponse.java

@@ -0,0 +1,14 @@
+package com.pinback.application.google.dto.response;
+
+import org.springframework.lang.Nullable;
+
+public record GoogleApiResponse(
+	String id,
+	String email,
+	Boolean verifiedEmail,
+	String name,
+	@Nullable String givenName,
+	@Nullable String familyName,
+	String picture
+) {
+}

application/src/main/java/com/pinback/application/google/dto/response/GoogleLoginResponse.java

@@ -0,0 +1,18 @@
+package com.pinback.application.google.dto.response;
+
+import java.util.UUID;
+
+public record GoogleLoginResponse(
+	boolean isUser,
+	UUID userId,
+	String email,
+	String accessToken
+) {
+	public static GoogleLoginResponse loggedIn(UUID userId, String email, String accessToken) {
+		return new GoogleLoginResponse(true, userId, email, accessToken);
+	}
+
+	public static GoogleLoginResponse tempLogin(UUID userId, String email) {
+		return new GoogleLoginResponse(false, userId, email, null);
+	}
+}

application/src/main/java/com/pinback/application/google/dto/response/GoogleTokenResponse.java

@@ -0,0 +1,14 @@
+package com.pinback.application.google.dto.response;
+
+import com.fasterxml.jackson.databind.PropertyNamingStrategies;
+import com.fasterxml.jackson.databind.annotation.JsonNaming;
+
+@JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
+public record GoogleTokenResponse(
+	String accessToken,
+	String expiresIn,
+	String tokenType,
+	String scope,
+	String idToken
+) {
+}

application/src/main/java/com/pinback/application/google/dto/response/GoogleUserInfoResponse.java

@@ -0,0 +1,9 @@
+package com.pinback.application.google.dto.response;
+
+public record GoogleUserInfoResponse(
+	String email
+) {
+	public static GoogleUserInfoResponse from(String email) {
+		return new GoogleUserInfoResponse(email);
+	}
+}

application/src/main/java/com/pinback/application/google/port/out/GoogleOAuthPort.java

@@ -0,0 +1,9 @@
+package com.pinback.application.google.port.out;
+
+import com.pinback.application.google.dto.response.GoogleUserInfoResponse;
+
+import reactor.core.publisher.Mono;
+
+public interface GoogleOAuthPort {
+	Mono<GoogleUserInfoResponse> fetchUserInfo(String code);
+}