[FEAT] Notification 단건 조회 API 구현

src/main/java/org/websoso/WSSServer/controller/NotificationController.java

@@ -6,10 +6,12 @@
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.ResponseEntity;
 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;
 import org.websoso.WSSServer.domain.User;
+import org.websoso.WSSServer.dto.notification.NotificationGetResponse;
 import org.websoso.WSSServer.dto.notification.NotificationsGetResponse;
 import org.websoso.WSSServer.service.NotificationService;
 import org.websoso.WSSServer.service.UserService;
@@ -31,4 +33,14 @@ public ResponseEntity<NotificationsGetResponse> getNotifications(Principal princ
                 .status(OK)
                 .body(notificationService.getNotifications(lastNotificationId, size, user));
     }
+
+    @GetMapping("/{notificationId}")
+    public ResponseEntity<NotificationGetResponse> getNotification(Principal principal,
+                                                                   @PathVariable("notificationId") Long notificationId) {
+        User user = userService.getUserOrException(Long.valueOf(principal.getName()));
+
+        return ResponseEntity
+                .status(OK)
+                .body(notificationService.getNotification(user, notificationId));
+    }
 }

src/main/java/org/websoso/WSSServer/domain/Notification.java

@@ -28,9 +28,9 @@ public class Notification extends BaseEntity {
     private String notificationTitle;
 
     @Column(nullable = false)
-    private String notificationDescription;
+    private String notificationBody;
 
-    private String notificationContent;
+    private String notificationDetail;
 
     @Column(nullable = false)
     private Long userId;
@@ -41,20 +41,20 @@ public class Notification extends BaseEntity {
     @JoinColumn(name = "notification_type_id", nullable = false)
     private NotificationType notificationType;
 
-    private Notification(String notificationTitle, String notificationDescription, String notificationContent,
+    private Notification(String notificationTitle, String notificationBody, String notificationDetail,
                          Long userId, Long feedId, NotificationType notificationType) {
         this.notificationTitle = notificationTitle;
-        this.notificationDescription = notificationDescription;
-        this.notificationContent = notificationContent;
+        this.notificationBody = notificationBody;
+        this.notificationDetail = notificationDetail;
         this.userId = userId;
         this.feedId = feedId;
         this.notificationType = notificationType;
     }
 
-    public static Notification create(String notificationTitle, String notificationDescription,
-                                      String notificationContent, Long userId, Long feedId,
+    public static Notification create(String notificationTitle, String notificationBody,
+                                      String notificationDetail, Long userId, Long feedId,
                                       NotificationType notificationType) {
-        return new Notification(notificationTitle, notificationDescription, notificationContent, userId, feedId,
+        return new Notification(notificationTitle, notificationBody, notificationDetail, userId, feedId,
                 notificationType);
     }
 }

src/main/java/org/websoso/WSSServer/dto/notification/NotificationGetResponse.java

@@ -0,0 +1,20 @@
+package org.websoso.WSSServer.dto.notification;
+
+import java.time.format.DateTimeFormatter;
+import org.websoso.WSSServer.domain.Notification;
+
+public record NotificationGetResponse(
+        String notificationTitle,
+        String notificationCreatedDate,
+        String notificationDetail
+) {
+    private static final String DATE_PATTERN = "yyyy.MM.dd";
+
+    static public NotificationGetResponse of(Notification notification) {
+        return new NotificationGetResponse(
+                notification.getNotificationTitle(),
+                notification.getCreatedDate().format(DateTimeFormatter.ofPattern(DATE_PATTERN)),
+                notification.getNotificationDetail()
+        );
+    }
+}

src/main/java/org/websoso/WSSServer/dto/notification/NotificationInfo.java

@@ -9,7 +9,7 @@ public record NotificationInfo(
         Long notificationId,
         String notificationImage,
         String notificationTitle,
-        String notificationDescription,
+        String notificationBody,
         String createdDate,
         Boolean isRead,
         Boolean isNotice,
@@ -26,7 +26,7 @@ static public NotificationInfo of(Notification notification, Boolean isRead) {
                 notification.getNotificationId(),
                 notification.getNotificationType().getNotificationTypeImage(),
                 notification.getNotificationTitle(),
-                notification.getNotificationDescription(),
+                notification.getNotificationBody(),
                 formatCreatedDate(notification.getCreatedDate()),
                 isRead,
                 notification.getNotificationType().getNotificationTypeName().equals("공지"),

src/main/java/org/websoso/WSSServer/exception/error/CustomNotificationError.java

@@ -0,0 +1,23 @@
+package org.websoso.WSSServer.exception.error;
+
+import static org.springframework.http.HttpStatus.BAD_REQUEST;
+import static org.springframework.http.HttpStatus.FORBIDDEN;
+import static org.springframework.http.HttpStatus.NOT_FOUND;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.springframework.http.HttpStatus;
+import org.websoso.WSSServer.exception.common.ICustomError;
+
+@AllArgsConstructor
+@Getter
+public enum CustomNotificationError implements ICustomError {
+
+    NOTIFICATION_NOT_FOUND("NOTIFICATION-001", "해당 ID를 가진 공지사항을 찾을 수 없습니다.", NOT_FOUND),
+    NOTIFICATION_READ_FORBIDDEN("NOTIFICATION-002", "해당 알림의 대상 유저가 아닙니다.", FORBIDDEN),
+    NOTIFICATION_TYPE_INVALID("NOTIFICATION-003", "해당 알림은 공지사항에 적합한 타입이 아닙니다.", BAD_REQUEST);
+
+    private final String code;
+    private final String description;
+    private final HttpStatus statusCode;
+}

src/main/java/org/websoso/WSSServer/exception/exception/CustomNotificationException.java

@@ -0,0 +1,13 @@
+package org.websoso.WSSServer.exception.exception;
+
+import lombok.Getter;
+import org.websoso.WSSServer.exception.common.AbstractCustomException;
+import org.websoso.WSSServer.exception.error.CustomNotificationError;
+
+@Getter
+public class CustomNotificationException extends AbstractCustomException {
+
+    public CustomNotificationException(CustomNotificationError customNotificationError, String message) {
+        super(customNotificationError, message);
+    }
+}

src/main/java/org/websoso/WSSServer/repository/ReadNotificationRepository.java

@@ -3,11 +3,14 @@
 import java.util.List;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
+import org.websoso.WSSServer.domain.Notification;
 import org.websoso.WSSServer.domain.ReadNotification;
 import org.websoso.WSSServer.domain.User;
 
 @Repository
 public interface ReadNotificationRepository extends JpaRepository<ReadNotification, Long> {
 
     List<ReadNotification> findAllByUser(User user);
+
+    boolean existsByUserAndNotification(User user, Notification notification);
 }

src/main/java/org/websoso/WSSServer/service/NotificationService.java

@@ -1,5 +1,9 @@
 package org.websoso.WSSServer.service;
 
+import static org.websoso.WSSServer.exception.error.CustomNotificationError.NOTIFICATION_NOT_FOUND;
+import static org.websoso.WSSServer.exception.error.CustomNotificationError.NOTIFICATION_READ_FORBIDDEN;
+import static org.websoso.WSSServer.exception.error.CustomNotificationError.NOTIFICATION_TYPE_INVALID;
+
 import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -11,8 +15,10 @@
 import org.websoso.WSSServer.domain.Notification;
 import org.websoso.WSSServer.domain.ReadNotification;
 import org.websoso.WSSServer.domain.User;
+import org.websoso.WSSServer.dto.notification.NotificationGetResponse;
 import org.websoso.WSSServer.dto.notification.NotificationInfo;
 import org.websoso.WSSServer.dto.notification.NotificationsGetResponse;
+import org.websoso.WSSServer.exception.exception.CustomNotificationException;
 import org.websoso.WSSServer.repository.NotificationRepository;
 import org.websoso.WSSServer.repository.ReadNotificationRepository;
 
@@ -25,6 +31,13 @@ public class NotificationService {
     private final NotificationRepository notificationRepository;
     private final ReadNotificationRepository readNotificationRepository;
 
+    @Transactional(readOnly = true)
+    public Notification getNotificationOrException(Long notificationId) {
+        return notificationRepository.findById(notificationId)
+                .orElseThrow(() -> new CustomNotificationException(NOTIFICATION_NOT_FOUND,
+                        "notification with the given id is not found"));
+    }
+
     @Transactional(readOnly = true)
     public NotificationsGetResponse getNotifications(Long lastNotificationId, int size, User user) {
         Slice<Notification> notifications = notificationRepository.findNotifications(lastNotificationId,
@@ -40,4 +53,33 @@ public NotificationsGetResponse getNotifications(Long lastNotificationId, int si
 
         return NotificationsGetResponse.of(notifications.hasNext(), notificationInfos);
     }
+
+    public NotificationGetResponse getNotification(User user, Long notificationId) {
+        Notification notification = getNotificationOrException(notificationId);
+        verifyIsNotice(notification);
+        validateNotificationRecipient(user, notification);
+        if (!readNotificationRepository.existsByUserAndNotification(user, notification)) {
+            readNotificationRepository.save(ReadNotification.create(notification, user));
+        }
+        return NotificationGetResponse.of(notification);
+    }
+
+    private void verifyIsNotice(Notification notification) {
+        Set<String> noticeTypes = Set.of("공지", "이벤트");
+        if (noticeTypes.contains(notification.getNotificationType().getNotificationTypeName())) {
+            return;
+        }
+        throw new CustomNotificationException(NOTIFICATION_TYPE_INVALID,
+                "Notification does not have a type suitable for a notice.");
+    }
+
+    private void validateNotificationRecipient(User user, Notification notification) {
+        Long userId = user.getUserId();
+        Long notificationUserId = notification.getUserId();
+        if (notificationUserId == 0 || notificationUserId.equals(userId)) {
+            return;
+        }
+        throw new CustomNotificationException(NOTIFICATION_READ_FORBIDDEN,
+                "User does not have permission to access this notification.");
+    }
 }