feat: 채팅 이미지 전송 구현

src/main/java/com/example/solidconnection/chat/controller/ChatMessageController.java

@@ -1,5 +1,6 @@
 package com.example.solidconnection.chat.controller;
 
+import com.example.solidconnection.chat.dto.ChatImageSendRequest;
 import com.example.solidconnection.chat.dto.ChatMessageSendRequest;
 import com.example.solidconnection.chat.service.ChatService;
 import com.example.solidconnection.security.authentication.TokenAuthentication;
@@ -29,4 +30,16 @@ public void sendChatMessage(
 
         chatService.sendChatMessage(chatMessageSendRequest, siteUserDetails.getSiteUser().getId(), roomId);
     }
+
+    @MessageMapping("/chat/{roomId}/image")
+    public void sendChatImage(
+            @DestinationVariable Long roomId,
+            @Valid @Payload ChatImageSendRequest chatImageSendRequest,
+            Principal principal
+    ) {
+        TokenAuthentication tokenAuthentication = (TokenAuthentication) principal;
+        SiteUserDetails siteUserDetails = (SiteUserDetails) tokenAuthentication.getPrincipal();
+
+        chatService.sendChatImage(chatImageSendRequest, siteUserDetails.getSiteUser().getId(), roomId);
+    }
 }

src/main/java/com/example/solidconnection/chat/domain/ChatAttachment.java

@@ -7,6 +7,7 @@
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
 import jakarta.persistence.ManyToOne;
 import lombok.AccessLevel;
 import lombok.Getter;
@@ -30,7 +31,7 @@ public class ChatAttachment extends BaseEntity {
     @Column(length = 500)
     private String thumbnailUrl;
 
-    @ManyToOne(fetch = FetchType.LAZY)
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
     private ChatMessage chatMessage;
 
     public ChatAttachment(boolean isImage, String url, String thumbnailUrl, ChatMessage chatMessage) {
@@ -42,4 +43,17 @@ public ChatAttachment(boolean isImage, String url, String thumbnailUrl, ChatMess
             chatMessage.getChatAttachments().add(this);
         }
     }
+
+    protected void setChatMessage(ChatMessage chatMessage) {
+        if (this.chatMessage == chatMessage) return;
+
+        if (this.chatMessage != null) {
+            this.chatMessage.getChatAttachments().remove(this);
+        }
+
+        this.chatMessage = chatMessage;
+        if (chatMessage != null && !chatMessage.getChatAttachments().contains(this)) {
+            chatMessage.getChatAttachments().add(this);
+        }
+    }
 }

src/main/java/com/example/solidconnection/chat/domain/ChatMessage.java

@@ -33,7 +33,7 @@ public class ChatMessage extends BaseEntity {
     @ManyToOne(fetch = FetchType.LAZY)
     private ChatRoom chatRoom;
 
-    @OneToMany(mappedBy = "chatMessage", cascade = CascadeType.ALL)
+    @OneToMany(mappedBy = "chatMessage", cascade = CascadeType.ALL, orphanRemoval = true)
     private final List<ChatAttachment> chatAttachments = new ArrayList<>();
 
     public ChatMessage(String content, long senderId, ChatRoom chatRoom) {
@@ -44,4 +44,9 @@ public ChatMessage(String content, long senderId, ChatRoom chatRoom) {
             chatRoom.getChatMessages().add(this);
         }
     }
+
+    public void addAttachment(ChatAttachment attachment) {
+        this.chatAttachments.add(attachment);
+        attachment.setChatMessage(this);
+    }
 }

src/main/java/com/example/solidconnection/chat/domain/MessageType.java

@@ -0,0 +1,6 @@
+package com.example.solidconnection.chat.domain;
+
+public enum MessageType {
+    TEXT,
+    IMAGE,
+}

src/main/java/com/example/solidconnection/chat/dto/ChatImageSendRequest.java

@@ -0,0 +1,14 @@
+package com.example.solidconnection.chat.dto;
+
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+import java.util.List;
+
+public record ChatImageSendRequest(
+        @NotNull(message = "이미지 URL 목록은 필수입니다")
+        @Size(min = 1, max = 10, message = "이미지는 1~10개까지 가능합니다")
+        List<@NotBlank(message = "이미지 URL은 필수입니다") String> imageUrls
+) {
+
+}

src/main/java/com/example/solidconnection/chat/dto/ChatMessageSendResponse.java

@@ -1,19 +1,38 @@
 package com.example.solidconnection.chat.dto;
 
 import com.example.solidconnection.chat.domain.ChatMessage;
+import com.example.solidconnection.chat.domain.MessageType;
+import java.util.List;
 
 public record ChatMessageSendResponse(
         long messageId,
         String content,
-        long senderId
+        long senderId,
+        MessageType messageType,
+        List<ChatAttachmentResponse> attachments
 ) {
 
     public static ChatMessageSendResponse from(ChatMessage chatMessage) {
+        MessageType messageType = chatMessage.getChatAttachments().isEmpty()
+                ? MessageType.TEXT
+                : MessageType.IMAGE;
+
+        List<ChatAttachmentResponse> attachments = chatMessage.getChatAttachments().stream()
+                .map(attachment -> ChatAttachmentResponse.of(
+                        attachment.getId(),
+                        attachment.getIsImage(),
+                        attachment.getUrl(),
+                        attachment.getThumbnailUrl(),
+                        attachment.getCreatedAt()
+                ))
+                .toList();
+
         return new ChatMessageSendResponse(
                 chatMessage.getId(),
                 chatMessage.getContent(),
-                chatMessage.getSenderId()
+                chatMessage.getSenderId(),
+                messageType,
+                attachments
         );
     }
-
 }

src/main/java/com/example/solidconnection/chat/service/ChatService.java

@@ -5,10 +5,12 @@
 import static com.example.solidconnection.common.exception.ErrorCode.INVALID_CHAT_ROOM_STATE;
 import static com.example.solidconnection.common.exception.ErrorCode.USER_NOT_FOUND;
 
+import com.example.solidconnection.chat.domain.ChatAttachment;
 import com.example.solidconnection.chat.domain.ChatMessage;
 import com.example.solidconnection.chat.domain.ChatParticipant;
 import com.example.solidconnection.chat.domain.ChatRoom;
 import com.example.solidconnection.chat.dto.ChatAttachmentResponse;
+import com.example.solidconnection.chat.dto.ChatImageSendRequest;
 import com.example.solidconnection.chat.dto.ChatMessageResponse;
 import com.example.solidconnection.chat.dto.ChatMessageSendRequest;
 import com.example.solidconnection.chat.dto.ChatMessageSendResponse;
@@ -195,6 +197,53 @@ public void sendChatMessage(ChatMessageSendRequest chatMessageSendRequest, long
         simpMessageSendingOperations.convertAndSend("/topic/chat/" + roomId, chatMessageResponse);
     }
 
+    @Transactional
+    public void sendChatImage(ChatImageSendRequest chatImageSendRequest, long siteUserId, long roomId) {
+        long senderId = chatParticipantRepository.findByChatRoomIdAndSiteUserId(roomId, siteUserId)
+                .orElseThrow(() -> new CustomException(CHAT_PARTICIPANT_NOT_FOUND))
+                .getId();
+
+        ChatRoom chatRoom = chatRoomRepository.findById(roomId)
+                .orElseThrow(() -> new CustomException(INVALID_CHAT_ROOM_STATE));
+
+        ChatMessage chatMessage = new ChatMessage(
+                "",
+                senderId,
+                chatRoom
+        );
+
+        for (String imageUrl : chatImageSendRequest.imageUrls()) {
+            String thumbnailUrl = generateThumbnailUrl(imageUrl);
+
+            ChatAttachment attachment = new ChatAttachment(true, imageUrl, thumbnailUrl, null);
+            chatMessage.addAttachment(attachment);
+        }
+
+        chatMessageRepository.save(chatMessage);
+
+        ChatMessageSendResponse chatMessageResponse = ChatMessageSendResponse.from(chatMessage);
+        simpMessageSendingOperations.convertAndSend("/topic/chat/" + roomId, chatMessageResponse);
+    }
+
+    private String generateThumbnailUrl(String originalUrl) {
+        try {
+            String fileName = originalUrl.substring(originalUrl.lastIndexOf('/') + 1);
+
+            String nameWithoutExt = fileName.substring(0, fileName.lastIndexOf('.'));
+            String extension = fileName.substring(fileName.lastIndexOf('.'));
+
+            String thumbnailFileName = nameWithoutExt + "_thumb" + extension;
+
+            String thumbnailUrl = originalUrl.replace("chat/images/", "chat/thumbnails/")
+                    .replace(fileName, thumbnailFileName);
+
+            return thumbnailUrl;
+
+        } catch (Exception e) {
+            return originalUrl;
+        }
+    }
+
     @Transactional
     public Long createMentoringChatRoom(Long mentoringId, Long mentorId, Long menteeId) {
         ChatRoom existingChatRoom = chatRoomRepository.findByMentoringId(mentoringId);

src/main/java/com/example/solidconnection/s3/controller/S3Controller.java

@@ -5,6 +5,7 @@
 import com.example.solidconnection.s3.dto.UploadedFileUrlResponse;
 import com.example.solidconnection.s3.dto.urlPrefixResponse;
 import com.example.solidconnection.s3.service.S3Service;
+import java.util.List;
 import lombok.RequiredArgsConstructor;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.http.ResponseEntity;
@@ -68,6 +69,14 @@ public ResponseEntity<UploadedFileUrlResponse> uploadLanguageImage(
         return ResponseEntity.ok(profileImageUrl);
     }
 
+    @PostMapping("/chat")
+    public ResponseEntity<List<UploadedFileUrlResponse>> uploadChatImage(
+            @RequestParam("files") List<MultipartFile> imageFiles
+    ) {
+        List<UploadedFileUrlResponse> chatImageUrls = s3Service.uploadFiles(imageFiles, ImgType.CHAT);
+        return ResponseEntity.ok(chatImageUrls);
+    }
+
     @GetMapping("/s3-url-prefix")
     public ResponseEntity<urlPrefixResponse> getS3UrlPrefix() {
         return ResponseEntity.ok(new urlPrefixResponse(s3Default, s3Uploaded, cloudFrontDefault, cloudFrontUploaded));

src/main/java/com/example/solidconnection/s3/domain/ImgType.java

@@ -4,7 +4,7 @@
 
 @Getter
 public enum ImgType {
-    PROFILE("profile"), GPA("gpa"), LANGUAGE_TEST("language"), COMMUNITY("community"), NEWS("news");
+    PROFILE("profile"), GPA("gpa"), LANGUAGE_TEST("language"), COMMUNITY("community"), NEWS("news"), CHAT("chat");
 
     private final String type;
 

src/main/java/com/example/solidconnection/s3/service/S3Service.java

@@ -35,7 +35,7 @@
 public class S3Service {
 
     private static final Logger log = LoggerFactory.getLogger(S3Service.class);
-    private static final long MAX_FILE_SIZE_MB = 1024 * 1024 * 3;
+    private static final long MAX_FILE_SIZE_MB = 1024 * 1024 * 5;
 
     private final AmazonS3Client amazonS3;
     private final SiteUserRepository siteUserRepository;
@@ -52,8 +52,8 @@ public class S3Service {
      * - 파일에 대한 메타 데이터를 생성한다.
      * - 임의의 랜덤한 문자열로 파일 이름을 생성한다.
      * - S3에 파일을 업로드한다.
-     * - 3mb 이상의 파일은 /origin/ 경로로 업로드하여 lambda 함수로 리사이징 진행한다.
-     * - 3mb 미만의 파일은 바로 업로드한다.
+     * - 5mb 이상의 파일은 /origin/ 경로로 업로드하여 lambda 함수로 리사이징 진행한다.
+     * - 5mb 미만의 파일은 바로 업로드한다.
      * */
     public UploadedFileUrlResponse uploadFile(MultipartFile multipartFile, ImgType imageFile) {
         // 파일 검증