✨ Feat/#315 채팅 내용 저장 기능 구현

backend/src/main/java/org/example/backend/domain/question/controller/QuestionController.java

@@ -9,10 +9,7 @@
 import org.example.backend.global.security.auth.CustomUserDetails;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.context.SecurityContextHolder;
-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.RestController;
+import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
 import java.util.UUID;
@@ -45,4 +42,11 @@ public ApiResponse<List<QuestionResponseDTO.beforeChatting>> getBeforeChatting(@
         List<QuestionResponseDTO.beforeChatting> result = questionService.getBeforeChatting(lectureId);
         return ApiResponse.onSuccess(result);
     }
+
+    // 채팅 내용 저장하기
+    @PostMapping("/chatting/after/{lectureId}")
+    public ApiResponse<String> afterChatting(@PathVariable("lectureId") UUID lectureId) {
+        questionService.saveChatting(lectureId);
+        return ApiResponse.onSuccess(null);
+    }
 }

backend/src/main/java/org/example/backend/domain/question/converter/QuestionConverter.java

@@ -1,9 +1,12 @@
 package org.example.backend.domain.question.converter;
 
 import lombok.RequiredArgsConstructor;
+import org.example.backend.domain.lecture.entity.Lecture;
 import org.example.backend.domain.question.dto.response.QuestionResponseDTO;
 import org.example.backend.domain.question.entity.Question;
+import org.example.backend.domain.user.entity.Role;
 import org.example.backend.domain.user.entity.SocialType;
+import org.example.backend.domain.user.entity.User;
 import org.example.backend.global.S3.service.S3Service;
 import org.springframework.stereotype.Component;
 
@@ -32,4 +35,13 @@ public QuestionResponseDTO.student toStudentQuestions(Question question) {
                 .timestamp(question.getTimestamp())
                 .build();
     }
+
+    public Question toQuestion(QuestionResponseDTO.afterChatting dto, Lecture lecture, User user) {
+        return Question.builder()
+                .lecture(lecture)
+                .timestamp(dto.getTimestamp())
+                .content(dto.getContent())
+                .user(user)
+                .build();
+    }
 }

backend/src/main/java/org/example/backend/domain/question/dto/response/QuestionResponseDTO.java

@@ -44,4 +44,15 @@ public static class beforeChatting {
         private Role role;
     }
 
+    @Builder
+    @Getter
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class afterChatting {
+        private String content;
+        private LocalDateTime timestamp;
+        private UUID senderId;
+        private Role role;
+    }
+
 }

backend/src/main/java/org/example/backend/domain/question/exception/QuestionErrorCode.java

@@ -11,7 +11,8 @@
 public enum QuestionErrorCode implements BaseErrorCode {
     _FORBIDDEN_LECTURE_ACCESS(HttpStatus.FORBIDDEN,"QUESTION403_1","해당 강의를 수강중인 학생만 조회가능합니다."),
     _CHAT_MESSAGE_SEND_FAIL(HttpStatus.INTERNAL_SERVER_ERROR, "QUESTION500_1", "채팅 메시지 전송에 실패했습니다."),
-    _INVALID_JSON_FORMAT(HttpStatus.BAD_REQUEST,"QUESTION400_1","저장된 채팅 데이터를 읽는 데 실패했습니다.");
+    _INVALID_JSON_FORMAT(HttpStatus.BAD_REQUEST,"QUESTION400_1","저장된 채팅 데이터를 읽는 데 실패했습니다."),
+    _FORBIDDEN_CHATTING_ACCESS(HttpStatus.FORBIDDEN,"QUESTION403_2","채팅 저장 권한은 강사에게만 있습니다.");
 
     private final HttpStatus httpStatus;
     private final String code;

backend/src/main/java/org/example/backend/domain/question/service/QuestionService.java

@@ -13,4 +13,6 @@ public interface QuestionService {
     List<QuestionResponseDTO.student> getStudentQuestions(UUID lectureId, User user);
     // 이전 채팅 내용 불러오개
     List<QuestionResponseDTO.beforeChatting> getBeforeChatting(UUID lectureId);
+    // 채팅 내용 저장
+    void saveChatting(UUID lectureId);
 }

backend/src/main/java/org/example/backend/domain/question/service/QuestionServiceImpl.java

@@ -3,13 +3,23 @@
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import lombok.RequiredArgsConstructor;
+import org.example.backend.domain.lecture.entity.Lecture;
+import org.example.backend.domain.lecture.exception.LectureErrorCode;
+import org.example.backend.domain.lecture.exception.LectureException;
+import org.example.backend.domain.lecture.repository.LectureRepository;
 import org.example.backend.domain.question.converter.QuestionConverter;
 import org.example.backend.domain.question.dto.response.QuestionResponseDTO;
+import org.example.backend.domain.question.entity.Question;
 import org.example.backend.domain.question.exception.QuestionErrorCode;
 import org.example.backend.domain.question.exception.QuestionException;
 import org.example.backend.domain.question.repository.QuestionRepository;
 import org.example.backend.domain.studentClass.repository.StudentClassRepository;
+import org.example.backend.domain.user.entity.Role;
 import org.example.backend.domain.user.entity.User;
+import org.example.backend.domain.user.exception.UserErrorCode;
+import org.example.backend.domain.user.exception.UserException;
+import org.example.backend.domain.user.repository.UserRepository;
+import org.example.backend.global.security.auth.CustomSecurityUtil;
 import org.springframework.data.redis.core.RedisTemplate;
 import org.springframework.stereotype.Service;
 
@@ -24,9 +34,12 @@ public class QuestionServiceImpl implements QuestionService {
 
     private final QuestionRepository questionRepository;
     private final StudentClassRepository studentClassRepository;
+    private final LectureRepository lectureRepository;
+    private final UserRepository userRepository;
     private final QuestionConverter questionConverter;
     private final RedisTemplate<String,String> redisTemplate;
     private final ObjectMapper objectMapper;
+    private final CustomSecurityUtil customSecurityUtil;
 
     @Override
     public List<QuestionResponseDTO.teacher> getTeacherQuestions(UUID lectureId, User user ) {
@@ -78,4 +91,59 @@ public List<QuestionResponseDTO.beforeChatting> getBeforeChatting(UUID lectureId
         }
         return chatList;
     }
+
+    @Override
+    public void saveChatting(UUID lectureId) {
+        // 1. 접근 권한 확인
+        Role role = customSecurityUtil.getUserRole();
+        if(role != Role.TEACHER){
+            throw new QuestionException(QuestionErrorCode._FORBIDDEN_CHATTING_ACCESS);
+        }
+
+        // 2. 강의 존재 확인
+        Lecture lecture = lectureRepository.findById(lectureId)
+                .orElseThrow(() -> new LectureException(LectureErrorCode.LECTURE_NOT_FOUND));
+
+        // 3. redis key 정의
+        String redisKey = "chat:lecture:" + lectureId;
+
+        // 4. redis에서 채팅 내역 가져오기
+        List<String> rawMessages = redisTemplate.opsForList().range(redisKey, 0, -1);
+
+        if(rawMessages == null || rawMessages.isEmpty()){
+            // 이전 내용이 없다면 저장 X
+            return;
+        }
+
+        // 5. JSON -> Entity 변환
+        List<Question> questionEntities = new ArrayList<>();
+        for(String raw: rawMessages){
+            try{
+                // JSON -> DTO
+                QuestionResponseDTO.afterChatting dto = objectMapper.readValue(raw, QuestionResponseDTO.afterChatting.class);
+
+                // 강사 메시지 저장 X
+                if(dto.getRole() == Role.TEACHER){
+                    continue;
+                }
+                // DTO -> Entity
+                User user = userRepository.findById(dto.getSenderId())
+                        .orElseThrow(() -> new UserException(UserErrorCode._USER_NOT_FOUND));
+
+                Question question = questionConverter.toQuestion(dto,lecture,user);
+
+                // Entity -> list에 넣기
+                questionEntities.add(question);
+            }
+            catch (JsonProcessingException e){
+                throw new QuestionException(QuestionErrorCode._INVALID_JSON_FORMAT);
+            }
+        }
+
+        // 6. DB 저장
+        questionRepository.saveAll(questionEntities);
+
+        // 7. Redis 비우기
+        redisTemplate.delete(redisKey);
+    }
 }