[Chat] Redis Stream 기반 채팅 메세지 저장&조회

src/main/java/com/back/web7_9_codecrete_be/domain/chats/controller/ChatMessageController.java

@@ -5,7 +5,7 @@
 import org.springframework.messaging.handler.annotation.MessageMapping;
 import org.springframework.stereotype.Controller;
 
-import com.back.web7_9_codecrete_be.domain.chats.dto.ChatMessageRequest;
+import com.back.web7_9_codecrete_be.domain.chats.dto.request.ChatMessageRequest;
 import com.back.web7_9_codecrete_be.domain.chats.service.ChatMessageService;
 
 import lombok.RequiredArgsConstructor;

src/main/java/com/back/web7_9_codecrete_be/domain/chats/controller/ChatMessageReadController.java

@@ -0,0 +1,67 @@
+package com.back.web7_9_codecrete_be.domain.chats.controller;
+
+import java.util.List;
+
+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 com.back.web7_9_codecrete_be.domain.chats.dto.response.ChatReadResponse;
+import com.back.web7_9_codecrete_be.domain.chats.service.ChatMessageReadService;
+import com.back.web7_9_codecrete_be.global.rsData.RsData;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import lombok.RequiredArgsConstructor;
+
+@Tag(name = "Chat", description = "채팅 메시지 조회 API")
+@RestController
+@RequestMapping("/api/v1/chats")
+@RequiredArgsConstructor
+public class ChatMessageReadController {
+
+	private final ChatMessageReadService chatMessageReadService;
+
+	@Operation(
+		summary = "채팅 메시지 조회 (cursor 기반 무한 스크롤)",
+		description = """
+			채팅 메시지를 cursor(before) 기준으로 조회합니다.
+
+			- before 미전달 시: 최신 메시지를 조회합니다.
+			- before 전달 시: 해당 cursor 이전의 메시지를 조회합니다.
+			"""
+	)
+	@GetMapping("/{concertId}/messages")
+	public RsData<List<ChatReadResponse>> getMessages(
+		@Parameter(
+			description = "공연 ID",
+			example = "1",
+			required = true
+		)
+		@PathVariable Long concertId,
+
+		@Parameter(
+			description = """
+				조회 기준 cursor (Redis Stream ID).
+				해당 값이 주어지면, 그 이전의 채팅 메시지를 조회합니다.
+				""",
+			example = "1734940012345-0",
+			required = false
+		)
+		@RequestParam(required = false) String before,
+
+		@Parameter(
+			description = "한 번에 조회할 메시지 개수 (기본값: 20)",
+			example = "20",
+			required = false
+		)
+		@RequestParam(required = false) Integer size
+	) {
+		return RsData.success(
+			chatMessageReadService.getMessages(concertId, before, size)
+		);
+	}
+}

src/main/java/com/back/web7_9_codecrete_be/domain/chats/controller/ChatRoomController.java

@@ -14,7 +14,7 @@
 import io.swagger.v3.oas.annotations.tags.Tag;
 import lombok.RequiredArgsConstructor;
 
-@Tag(name = "Chat Room", description = "공연 채팅방 입장 및 퇴장 API")
+@Tag(name = "Chat", description = "공연 채팅방 입장 API")
 @RestController
 @RequestMapping("/api/v1/chat-room")
 @RequiredArgsConstructor
@@ -34,8 +34,13 @@ public class ChatRoomController {
 			Redis Stream 기반 과거 채팅과 실시간 채팅을 수신합니다.
 			""" )
 	@ApiResponse( responseCode = "200", description = "채팅방 입장에 성공하였습니다." )
-	@ApiResponse( responseCode = "403", description = "로그인이 필요합니다." )
-	@ApiResponse( responseCode = "403", description = "채팅 가능한 기간이 아닙니다." )
+	@ApiResponse(
+		responseCode = "403",
+		description = """
+			- 로그인이 필요합니다.
+			- 채팅 가능한 기간이 아닙니다.
+		"""
+	)
 	@ApiResponse( responseCode = "404", description = "콘서트가 존재하지 않습니다." )
 	@PostMapping("/concert/{concertId}/join")
 	public RsData<Void> joinChatRoom(@PathVariable Long concertId) {

src/main/java/com/back/web7_9_codecrete_be/domain/chats/controller/ChatStompDocsController.java

@@ -4,8 +4,8 @@
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
-import com.back.web7_9_codecrete_be.domain.chats.dto.ChatMessageRequest;
-import com.back.web7_9_codecrete_be.domain.chats.dto.ChatMessageResponse;
+import com.back.web7_9_codecrete_be.domain.chats.dto.request.ChatMessageRequest;
+import com.back.web7_9_codecrete_be.domain.chats.dto.response.ChatMessageResponse;
 
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.media.Content;
@@ -27,7 +27,7 @@ public class ChatStompDocsController {
         ```
         ws://localhost:8080/ws-chat
         or
-        wss://www.naeconcertbutakhae.shop/ws-chat
+        wss://api.naeconcertbutakhae.shop/ws-chat
         ```
 
         #### 2️⃣ SEND Destination

src/main/java/com/back/web7_9_codecrete_be/domain/chats/dto/ChatMessageRequest.java → src/main/java/com/back/web7_9_codecrete_be/domain/chats/dto/request/ChatMessageRequest.java

@@ -1,4 +1,4 @@
-package com.back.web7_9_codecrete_be.domain.chats.dto;
+package com.back.web7_9_codecrete_be.domain.chats.dto.request;
 
 import io.swagger.v3.oas.annotations.media.Schema;
 import lombok.AllArgsConstructor;

src/main/java/com/back/web7_9_codecrete_be/domain/chats/dto/ChatMessageResponse.java → src/main/java/com/back/web7_9_codecrete_be/domain/chats/dto/response/ChatMessageResponse.java

@@ -1,4 +1,4 @@
-package com.back.web7_9_codecrete_be.domain.chats.dto;
+package com.back.web7_9_codecrete_be.domain.chats.dto.response;
 
 import java.time.LocalDateTime;
 

src/main/java/com/back/web7_9_codecrete_be/domain/chats/dto/response/ChatReadResponse.java

@@ -0,0 +1,35 @@
+package com.back.web7_9_codecrete_be.domain.chats.dto.response;
+
+import java.time.LocalDateTime;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Schema(description = "채팅 메시지 조회 응답")
+public class ChatReadResponse {
+
+	@Schema(description = "Redis Stream 메시지 ID (before로 전달하면, 해당 메시지 이전 메시지를 조회할 수 있습니다)", example = "1700000123456-0")
+	private String messageId;
+
+	@Schema(description = "공연 ID", example = "1")
+	private Long concertId;
+
+	@Schema(description = "발신자 ID", example = "2")
+	private Long senderId;
+
+	@Schema(description = "발신자 닉네임", example = "테스트 유저")
+	private String senderName;
+
+	@Schema(description = "메시지 내용", example = "안녕하세요")
+	private String content;
+
+	@Schema(description = "전송 시각")
+	private LocalDateTime sentDate;
+}

src/main/java/com/back/web7_9_codecrete_be/domain/chats/dto/response/ChatUserCache.java

@@ -0,0 +1,14 @@
+package com.back.web7_9_codecrete_be.domain.chats.dto.response;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+@AllArgsConstructor
+public class ChatUserCache {
+
+	private Long userId;
+	private String nickname;
+}

src/main/java/com/back/web7_9_codecrete_be/domain/chats/repository/ChatStreamRepository.java

@@ -0,0 +1,128 @@
+package com.back.web7_9_codecrete_be.domain.chats.repository;
+
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+import org.springframework.data.domain.Range;
+import org.springframework.data.redis.connection.Limit;
+import org.springframework.data.redis.connection.stream.MapRecord;
+import org.springframework.data.redis.connection.stream.StreamRecords;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.stereotype.Repository;
+
+import com.back.web7_9_codecrete_be.domain.chats.dto.response.ChatMessageResponse;
+import com.back.web7_9_codecrete_be.domain.chats.dto.response.ChatReadResponse;
+
+import lombok.RequiredArgsConstructor;
+
+@Repository
+@RequiredArgsConstructor
+public class ChatStreamRepository {
+
+	private final RedisTemplate<String, Object> redisTemplate;
+
+	private String streamKey(Long concertId) {
+		return "chat:stream:" + concertId;
+	}
+
+	/** 저장 */
+	public void save(ChatMessageResponse message) {
+		String key = streamKey(message.getConcertId());
+
+		Map<String, String> fields = new HashMap<>();
+		fields.put("concertId", message.getConcertId().toString());
+		fields.put("senderId", message.getSenderId().toString());
+		fields.put("senderName", message.getSenderName());
+		fields.put("content", message.getContent());
+		fields.put("sentDate", message.getSentDate().toString());
+
+		redisTemplate.opsForStream().add(
+			StreamRecords.newRecord()
+				.in(key)
+				.ofMap(fields)
+		);
+	}
+
+	public boolean hasTtl(Long concertId) {
+		Long ttl = redisTemplate.getExpire(streamKey(concertId));
+		return ttl != null && ttl >= 0;
+	}
+
+	public void setTtl(Long concertId, Duration ttl) {
+		redisTemplate.expire(streamKey(concertId), ttl);
+	}
+
+	/** 조회 */
+	// 채팅방 진입시 가장 최신 메시지 size개 조회
+	public List<ChatReadResponse> findLatest(Long concertId, int size) {
+
+		List<MapRecord<String, Object, Object>> records =
+			redisTemplate.opsForStream().reverseRange(
+				streamKey(concertId),
+				Range.unbounded(),
+				Limit.limit().count(size)
+			);
+
+		return toResponses(records);
+	}
+
+	// cursor(before) 기반 과거 메시지 조회
+	// beforeMessageId보다 이전에 있던 메시지들 중 최신 size개 조회
+	public List<ChatReadResponse> findBefore(
+		Long concertId,
+		String beforeMessageId,
+		int size
+	) {
+		String exclusiveBeforeId = exclusiveBefore(beforeMessageId);
+
+		List<MapRecord<String, Object, Object>> records =
+			redisTemplate.opsForStream().reverseRange(
+				streamKey(concertId),
+				Range.leftOpen("0-0", exclusiveBeforeId),
+				Limit.limit().count(size)
+			);
+
+		return toResponses(records);
+	}
+
+	private List<ChatReadResponse> toResponses(
+		List<MapRecord<String, Object, Object>> records
+	) {
+		if (records == null || records.isEmpty()) {
+			return List.of();
+		}
+
+		return records.stream()
+			.map(record -> {
+				Map<Object, Object> v = record.getValue();
+
+				return new ChatReadResponse(
+					record.getId().getValue(),
+					Long.valueOf(v.get("concertId").toString()),
+					Long.valueOf(v.get("senderId").toString()),
+					v.get("senderName").toString(),
+					v.get("content").toString(),
+					LocalDateTime.parse(v.get("sentDate").toString())
+				);
+			})
+			.filter(Objects::nonNull)
+			.toList();
+	}
+
+	private String exclusiveBefore(String messageId) {
+		String[] parts = messageId.split("-");
+		long time = Long.parseLong(parts[0]); // 밀리초 타임스탬프
+		long seq = Long.parseLong(parts[1]); // 같은 밀리초 내 순번
+
+		if (seq > 0) {
+			return time + "-" + (seq - 1);
+		}
+
+		// seq == 0 인 경우, timestamp를 1 감소
+		return (time - 1) + "-0";
+	}
+}

src/main/java/com/back/web7_9_codecrete_be/domain/chats/service/ChatMessageReadService.java

@@ -0,0 +1,39 @@
+package com.back.web7_9_codecrete_be.domain.chats.service;
+
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+
+import com.back.web7_9_codecrete_be.domain.chats.dto.response.ChatReadResponse;
+import com.back.web7_9_codecrete_be.domain.chats.repository.ChatStreamRepository;
+
+import lombok.RequiredArgsConstructor;
+
+@Service
+@RequiredArgsConstructor
+public class ChatMessageReadService {
+
+	private static final int DEFAULT_SIZE = 20;
+	private static final int MAX_SIZE = 50;
+
+	private final ChatStreamRepository chatStreamRepository;
+
+	public List<ChatReadResponse> getMessages(
+		Long concertId,
+		String before,
+		Integer size
+	) {
+		int limit = Math.min(
+			size != null ? size : DEFAULT_SIZE,
+			MAX_SIZE
+		);
+
+		// 최초 진입
+		if (before == null || before.isBlank()) {
+			return chatStreamRepository.findLatest(concertId, limit);
+		}
+
+		// 이전 메시지 조회 (무한 스크롤)
+		return chatStreamRepository.findBefore(concertId, before, limit);
+	}
+}