[Feat] Q&A 페이지 SSE 실시간 갱신 적용

backend/src/main/java/com/example/Piroin/project/domain/question/controller/QuestionController.java

@@ -35,8 +35,12 @@ public ResponseEntity<ApiResponse<QuestionResDTO.QuestionRoomResponse>> getQuest
     // text/event-stream으로 연결을 유지하며, 댓글 생성 같은 목록 갱신 이벤트를 받는다.
     // 인증 헤더가 필요하므로 프론트에서는 기본 EventSource 대신 fetch 기반 SSE 클라이언트로 구독한다.
     @GetMapping(value = "/api/sessions/{sessionId}/questions/events", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
-    public SseEmitter subscribeQuestionEvents(@PathVariable Long sessionId) {
-        return questionService.subscribeQuestionEvents(sessionId);
+    public ResponseEntity<SseEmitter> subscribeQuestionEvents(@PathVariable Long sessionId) {
+        return ResponseEntity.ok()
+                .contentType(MediaType.TEXT_EVENT_STREAM)
+                .header("Cache-Control", "no-cache")
+                .header("X-Accel-Buffering", "no")
+                .body(questionService.subscribeQuestionEvents(sessionId));
     }
 
     // 질문 상세 조회

backend/src/main/java/com/example/Piroin/project/domain/question/dto/QuestionResDTO.java

@@ -197,6 +197,17 @@ public record CommentCreatedEvent(
     ) {
     }
 
+    // 댓글 수정/삭제 시 SSE로 내려가는 목록 갱신 이벤트 응답
+    public record CommentUpdatedEvent(
+            String type,
+            Long sessionId,
+            Long questionId,
+            Boolean isResolved,
+            Integer commentCount,
+            List<PreviewCommentResponse> previewComments
+    ) {
+    }
+
     // O/X 클릭 직후 응답. selectedChoice가 null이면 같은 선택지를 다시 눌러 취소된 상태다.
     public record UnderstandingResponseResult(
             Long checkId,
@@ -243,6 +254,19 @@ public record QuestionCreatedEvent(
     ) {
     }
 
+    // 좋아요, 해결 상태, 본문 수정, 삭제처럼 기존 질문의 상태가 바뀔 때 내려가는 SSE 이벤트
+    public record QuestionUpdatedEvent(
+            String type,
+            Long sessionId,
+            Long questionId,
+            String content,
+            Boolean isResolved,
+            Integer likeCount,
+            Boolean isDeleted,
+            LocalDateTime updatedAt
+    ) {
+    }
+
     // 운영진이 이해도 체크를 생성했을 때 SSE로 내려가는 이벤트.
     // 같은 세션 질문방을 보고 있는 모든 클라이언트에게 전파된다.
     public record UnderstandingCheckCreatedEvent(

backend/src/main/java/com/example/Piroin/project/domain/question/service/QuestionEventService.java

@@ -45,11 +45,21 @@ public void publishCommentCreated(Long sessionId, QuestionResDTO.CommentCreatedE
         broadcast(sessionId, "comment-created", event);
     }
 
+    // 댓글 수정/삭제 이벤트를 같은 세션 질문방을 구독 중인 모든 클라이언트에게 전파한다.
+    public void publishCommentUpdated(Long sessionId, QuestionResDTO.CommentUpdatedEvent event) {
+        broadcast(sessionId, "comment-updated", event);
+    }
+
     // 질문 등록 이벤트를 같은 세션 질문방을 구독 중인 모든 클라이언트에게 전파한다.
     public void publishQuestionCreated(Long sessionId, QuestionResDTO.QuestionCreatedEvent event) {
         broadcast(sessionId, "question-created", event);
     }
 
+    // 질문 상태 변경 이벤트를 같은 세션 질문방을 구독 중인 모든 클라이언트에게 전파한다.
+    public void publishQuestionUpdated(Long sessionId, QuestionResDTO.QuestionUpdatedEvent event) {
+        broadcast(sessionId, "question-updated", event);
+    }
+
     // 이해도 체크 생성 이벤트를 같은 세션 질문방을 구독 중인 모든 클라이언트에게 전파한다.
     public void publishUnderstandingCheckCreated(Long sessionId, QuestionResDTO.UnderstandingCheckCreatedEvent event) {
         broadcast(sessionId, "understanding-check-created", event);

backend/src/main/java/com/example/Piroin/project/domain/question/service/QuestionService.java

@@ -281,7 +281,7 @@ public QuestionResDTO.LikeRes toggleLike(Long questionId, Long userId) {
         Question question = findQuestion(questionId);
 
         // 이미 좋아요를 눌렀는지 확인
-        return questionLikeRepository.findByQuestionAndUser(question, loginUser)
+        QuestionResDTO.LikeRes result = questionLikeRepository.findByQuestionAndUser(question, loginUser)
                 .map(existingLike -> {
                     // 이미 눌렀으면 → 취소 (삭제 + likeCount -1)
                     questionLikeRepository.delete(existingLike);
@@ -298,6 +298,9 @@ public QuestionResDTO.LikeRes toggleLike(Long questionId, Long userId) {
                     question.increaseLikeCount();
                     return new QuestionResDTO.LikeRes(question.getId(), question.getLikeCount(), true);
                 });
+
+        publishQuestionUpdatedEventAfterCommit(question, false);
+        return result;
     }
 
     // 질문 수정
@@ -313,6 +316,8 @@ public QuestionResDTO.UpdateDeleteRes updateQuestion(
 
         question.updateContent(request.getContent());
 
+        publishQuestionUpdatedEventAfterCommit(question, false);
+
         return new QuestionResDTO.UpdateDeleteRes(
                 question.getId(), question.getContent(),
                 question.getUpdatedAt(), question.getDeletedAt()
@@ -328,6 +333,8 @@ public QuestionResDTO.UpdateDeleteRes deleteQuestion(Long questionId, Long userI
 
         question.softDelete();
 
+        publishQuestionUpdatedEventAfterCommit(question, true);
+
         return new QuestionResDTO.UpdateDeleteRes(
                 question.getId(), question.getContent(),
                 question.getUpdatedAt(), question.getDeletedAt()
@@ -347,6 +354,8 @@ public QuestionResDTO.CommentUpdateDeleteRes updateComment(
 
         comment.updateContent(request.getContent());
 
+        publishCommentUpdatedEventAfterCommit(comment.getQuestion());
+
         return new QuestionResDTO.CommentUpdateDeleteRes(
                 comment.getId(), comment.getContent(),
                 comment.getUpdatedAt(), comment.getDeletedAt()
@@ -362,6 +371,8 @@ public QuestionResDTO.CommentUpdateDeleteRes deleteComment(Long commentId, Long
 
         comment.softDelete();
 
+        publishCommentUpdatedEventAfterCommit(comment.getQuestion());
+
         return new QuestionResDTO.CommentUpdateDeleteRes(
                 comment.getId(), comment.getContent(),
                 comment.getUpdatedAt(), comment.getDeletedAt()
@@ -379,6 +390,8 @@ public QuestionResDTO.StatusUpdateRes updateQuestionStatus(Long questionId, Long
         Question question = findQuestion(questionId);
         question.markResolved();
 
+        publishQuestionUpdatedEventAfterCommit(question, false);
+
         return new QuestionResDTO.StatusUpdateRes(
                 question.getId(), question.getIsResolved(), question.getUpdatedAt()
         );
@@ -742,6 +755,32 @@ private void publishCommentCreatedEventAfterCommit(Question question) {
         publishAfterCommit(() -> questionEventService.publishCommentCreated(sessionId, event));
     }
 
+    private void publishCommentUpdatedEventAfterCommit(Question question) {
+        Long sessionId = question.getSession().getId();
+        Long questionId = question.getId();
+        List<Long> questionIds = List.of(questionId);
+
+        Map<Long, Integer> commentCounts = new HashMap<>();
+        questionCommentRepository.countByQuestionIds(questionIds)
+                .forEach(row -> commentCounts.put(row.getQuestionId(), Math.toIntExact(row.getCommentCount())));
+
+        Map<Long, List<QuestionResDTO.PreviewCommentResponse>> previewComments = new HashMap<>();
+        questionCommentRepository.findPreviewCommentsByQuestionIds(questionIds)
+                .forEach(row -> previewComments.computeIfAbsent(row.getQuestionId(), key -> new ArrayList<>())
+                        .add(toPreviewCommentResponse(question, row)));
+
+        QuestionResDTO.CommentUpdatedEvent event = new QuestionResDTO.CommentUpdatedEvent(
+                "COMMENT_UPDATED",
+                sessionId,
+                questionId,
+                question.getIsResolved(),
+                commentCounts.getOrDefault(questionId, 0),
+                previewComments.getOrDefault(questionId, List.of())
+        );
+
+        publishAfterCommit(() -> questionEventService.publishCommentUpdated(sessionId, event));
+    }
+
     private void publishQuestionCreatedEventAfterCommit(Question question) {
         Long sessionId = question.getSession().getId();
 
@@ -759,6 +798,23 @@ private void publishQuestionCreatedEventAfterCommit(Question question) {
         publishAfterCommit(() -> questionEventService.publishQuestionCreated(sessionId, event));
     }
 
+    private void publishQuestionUpdatedEventAfterCommit(Question question, boolean isDeleted) {
+        Long sessionId = question.getSession().getId();
+
+        QuestionResDTO.QuestionUpdatedEvent event = new QuestionResDTO.QuestionUpdatedEvent(
+                "QUESTION_UPDATED",
+                sessionId,
+                question.getId(),
+                question.getContent(),
+                question.getIsResolved(),
+                question.getLikeCount(),
+                isDeleted,
+                question.getUpdatedAt()
+        );
+
+        publishAfterCommit(() -> questionEventService.publishQuestionUpdated(sessionId, event));
+    }
+
     private void publishUnderstandingCheckCreatedEventAfterCommit(
             Long sessionId, UnderstandingCheck check, int attendanceCount
     ) {