[260412] release: 사용자 언어 설정 API 추가 및 관리자 API 접근 제한

src/main/java/com/example/konnect_backend/domain/auth/service/DataMergeServiceImpl.java

@@ -40,11 +40,12 @@ public void mergeGuestToUser(String deviceUuid, Long userId) {
         User targetUser = userRepository.findById(userId)
                 .orElseThrow(() -> new GeneralException(ErrorStatus.USER_NOT_FOUND));
 
-        if (device.getLanguage() != null) {
+        // 게스트에서 선택한 언어를 최초 1회만 회원에게 승계
+        if (targetUser.getLanguage() == null && device.getLanguage() != null) {
             targetUser.updateLanguage(device.getLanguage());
         }
 
-        // 무조건 최신 유저로 업데이트
+        // 현재 디바이스는 최신 로그인 유저에 연결
         device.updateUser(targetUser);
 
         // 데이터 이전

src/main/java/com/example/konnect_backend/domain/user/controller/UserController.java

@@ -1,9 +1,8 @@
 // src/main/java/com/example/konnect_backend/domain/user/controller/UserController.java
 package com.example.konnect_backend.domain.user.controller;
 
-import com.example.konnect_backend.domain.user.dto.ChildDto;
-import com.example.konnect_backend.domain.user.dto.ChildUpdateDto;
-import com.example.konnect_backend.domain.user.dto.UserInfoDto;
+import com.example.konnect_backend.domain.user.dto.*;
+import com.example.konnect_backend.domain.user.service.LanguagePreferenceService;
 import com.example.konnect_backend.domain.user.service.UserService;
 import com.example.konnect_backend.global.ApiResponse;
 import io.swagger.v3.oas.annotations.Operation;
@@ -21,6 +20,7 @@
 public class UserController {
 
     private final UserService userService;
+    private final LanguagePreferenceService languagePreferenceService;
 
     @PostMapping("/children")
     @Operation(summary = "자녀 추가", description = "현재 로그인한 사용자에게 자녀를 추가합니다.")
@@ -53,4 +53,37 @@ public ApiResponse<UserInfoDto> getUserInfo() {
         return ApiResponse.onSuccess(userService.getUserInfo());
     }
 
+    @PatchMapping("/language")
+    @Operation(
+            summary = "사용자 언어 변경",
+            description = """
+                    로그인 상태면 User.language를 변경합니다.
+                    비로그인 상태면 X-Device-Id를 기준으로 Device.language를 변경합니다.
+                    로그인 상태에서 X-Device-Id를 함께 보내면 Device.language도 함께 동기화합니다.
+                    """
+    )
+    public ApiResponse<LanguageResponse> updateLanguage(
+            @RequestHeader(value = "X-Device-Id", required = false) String deviceUuid,
+            @Valid @RequestBody UpdateLanguageRequest request
+    ) {
+        return ApiResponse.onSuccess(
+                languagePreferenceService.updateLanguage(deviceUuid, request.getLanguage())
+        );
+    }
+
+    @GetMapping("/language")
+    @Operation(
+            summary = "사용자 언어 조회",
+            description = """
+                    로그인 상태면 User.language를 조회합니다.
+                    비로그인 상태면 X-Device-Id를 기준으로 Device.language를 조회합니다.
+                    """
+    )
+    public ApiResponse<LanguageResponse> getLanguage(
+            @RequestHeader(value = "X-Device-Id", required = false) String deviceUuid
+    ) {
+        return ApiResponse.onSuccess(
+                languagePreferenceService.getLanguage(deviceUuid)
+        );
+    }
 }

src/main/java/com/example/konnect_backend/domain/user/dto/LanguageResponse.java

@@ -0,0 +1,15 @@
+package com.example.konnect_backend.domain.user.dto;
+
+import com.example.konnect_backend.domain.user.entity.status.Language;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+@AllArgsConstructor
+public class LanguageResponse {
+
+    private Language language;
+    private boolean loggedIn;
+}

src/main/java/com/example/konnect_backend/domain/user/dto/UpdateLanguageRequest.java

@@ -0,0 +1,14 @@
+package com.example.konnect_backend.domain.user.dto;
+
+import com.example.konnect_backend.domain.user.entity.status.Language;
+import jakarta.validation.constraints.NotNull;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class UpdateLanguageRequest {
+
+    @NotNull
+    private Language language;
+}

src/main/java/com/example/konnect_backend/domain/user/service/DeviceService.java

@@ -7,10 +7,11 @@
 import com.example.konnect_backend.global.code.status.ErrorStatus;
 import com.example.konnect_backend.global.exception.GeneralException;
 import lombok.RequiredArgsConstructor;
-
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
+import java.time.LocalDateTime;
+
 @Service
 @RequiredArgsConstructor
 public class DeviceService {
@@ -20,14 +21,11 @@ public class DeviceService {
 
     @Transactional
     public void registerDevice(String deviceUuid, Language language) {
-        if (deviceUuid == null || deviceUuid.isBlank()) {
-            throw new GeneralException(ErrorStatus.INVALID_DEVICE);
-        }
+        validateDeviceUuid(deviceUuid);
 
         deviceRepository.findById(deviceUuid)
                 .map(device -> {
-                    // 이미 존재하면 language 업데이트
-                    if ( language != null) {
+                    if (language != null) {
                         device.updateLanguage(language);
                     }
                     return device;
@@ -36,24 +34,50 @@ public void registerDevice(String deviceUuid, Language language) {
                         deviceRepository.save(
                                 Device.builder()
                                         .deviceUuid(deviceUuid)
-                                        .language(language) // 추가
+                                        .language(language)
+                                        .createdAt(LocalDateTime.now())
+                                        .lastUsedAt(LocalDateTime.now())
                                         .build()
                         )
                 );
     }
 
-
     @Transactional
     public Device findOrCreateDevice(String deviceUuid) {
+        validateDeviceUuid(deviceUuid);
 
         return deviceRepository.findById(deviceUuid)
                 .orElseGet(() ->
                         deviceRepository.save(
                                 Device.builder()
                                         .deviceUuid(deviceUuid)
+                                        .createdAt(LocalDateTime.now())
+                                        .lastUsedAt(LocalDateTime.now())
                                         .build()
                         )
                 );
     }
 
+    @Transactional
+    public void updateLanguage(String deviceUuid, Language language) {
+        validateDeviceUuid(deviceUuid);
+
+        Device device = findOrCreateDevice(deviceUuid);
+        device.updateLanguage(language);
+    }
+
+    @Transactional(readOnly = true)
+    public Language getLanguage(String deviceUuid) {
+        validateDeviceUuid(deviceUuid);
+
+        return deviceRepository.findById(deviceUuid)
+                .map(Device::getLanguage)
+                .orElse(null);
+    }
+
+    private void validateDeviceUuid(String deviceUuid) {
+        if (deviceUuid == null || deviceUuid.isBlank()) {
+            throw new GeneralException(ErrorStatus.INVALID_DEVICE);
+        }
+    }
 }

src/main/java/com/example/konnect_backend/domain/user/service/LanguagePreferenceService.java

@@ -0,0 +1,78 @@
+package com.example.konnect_backend.domain.user.service;
+
+import com.example.konnect_backend.domain.user.dto.LanguageResponse;
+import com.example.konnect_backend.domain.user.entity.status.Language;
+import com.example.konnect_backend.global.code.status.ErrorStatus;
+import com.example.konnect_backend.global.exception.GeneralException;
+import com.example.konnect_backend.global.security.SecurityUtil;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+public class LanguagePreferenceService {
+
+    private final UserService userService;
+    private final DeviceService deviceService;
+
+    @Transactional
+    public LanguageResponse updateLanguage(String deviceUuid, Language language) {
+        Long userId = SecurityUtil.getCurrentUserIdOrNull();
+
+        if (language == null) {
+            throw new GeneralException(ErrorStatus._BAD_REQUEST);
+        }
+
+        // 로그인 사용자
+        if (userId != null) {
+            userService.updateLanguage(userId, language);
+
+            // 선택적으로 디바이스 언어도 동기화
+            if (deviceUuid != null && !deviceUuid.isBlank()) {
+                deviceService.updateLanguage(deviceUuid, language);
+            }
+
+            return LanguageResponse.builder()
+                    .language(language)
+                    .loggedIn(true)
+                    .build();
+        }
+
+        // 비로그인 사용자
+        if (deviceUuid == null || deviceUuid.isBlank()) {
+            throw new GeneralException(ErrorStatus.INVALID_DEVICE);
+        }
+
+        deviceService.updateLanguage(deviceUuid, language);
+
+        return LanguageResponse.builder()
+                .language(language)
+                .loggedIn(false)
+                .build();
+    }
+
+    public LanguageResponse getLanguage(String deviceUuid) {
+        Long userId = SecurityUtil.getCurrentUserIdOrNull();
+
+        // 로그인 상태면 무조건 User.language 우선
+        if (userId != null) {
+            Language language = userService.getLanguage(userId);
+            return LanguageResponse.builder()
+                    .language(language)
+                    .loggedIn(true)
+                    .build();
+        }
+
+        if (deviceUuid == null || deviceUuid.isBlank()) {
+            throw new GeneralException(ErrorStatus.INVALID_DEVICE);
+        }
+
+        Language language = deviceService.getLanguage(deviceUuid);
+        return LanguageResponse.builder()
+                .language(language)
+                .loggedIn(false)
+                .build();
+    }
+}

src/main/java/com/example/konnect_backend/domain/user/service/UserService.java

@@ -6,6 +6,7 @@
 import com.example.konnect_backend.domain.user.dto.UserInfoDto;
 import com.example.konnect_backend.domain.user.entity.Child;
 import com.example.konnect_backend.domain.user.entity.User;
+import com.example.konnect_backend.domain.user.entity.status.Language;
 import com.example.konnect_backend.domain.user.repository.ChildRepository;
 import com.example.konnect_backend.domain.user.repository.UserRepository;
 import com.example.konnect_backend.global.code.status.ErrorStatus;
@@ -127,4 +128,20 @@ public UserInfoDto getUserInfo(){
                 .language(user.getLanguage())
                 .build();
     }
+
+    @Transactional
+    public void updateLanguage(Long userId, Language language) {
+        User user = userRepository.findById(userId)
+                .orElseThrow(() -> new GeneralException(ErrorStatus.USER_NOT_FOUND));
+
+        user.updateLanguage(language);
+    }
+
+    @Transactional(readOnly = true)
+    public Language getLanguage(Long userId) {
+        User user = userRepository.findById(userId)
+                .orElseThrow(() -> new GeneralException(ErrorStatus.USER_NOT_FOUND));
+
+        return user.getLanguage();
+    }
 }

src/main/java/com/example/konnect_backend/global/config/WebSecurityConfig.java

@@ -57,8 +57,8 @@ public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Excepti
                                 "/swagger-resources/**",
                                 "/webjars/**"
                         ).permitAll()
-                        .requestMatchers("/api/auth/**", "/api/schools/**", "/api/device/**", "/api/ai/**", "/api/usage/**", "/api/message/**").permitAll()
-                        .requestMatchers("/api/admin/**").permitAll() // Todo 관리자만 허용해야 함, 테스트 위해 모두 허용
+                        .requestMatchers("/api/auth/**", "/api/schools/**", "/api/device/**", "/api/ai/**", "/api/usage/**", "/api/message/**", "/api/users/language").permitAll()
+                        .requestMatchers("/api/admin/**").denyAll() // Todo 관리자만 허용 필요
                         .requestMatchers("/api/ws/**", "/ws/**").permitAll()
                         .requestMatchers("/login/oauth2/**", "/oauth2/**").permitAll()
                         .requestMatchers("/public/**").permitAll()