히스토리서버 채널별 과거 채팅 조회 api(정방향) 구현

src/backend/history_server/build.gradle

@@ -22,12 +22,19 @@ repositories {
 }
 
 dependencies {
+	//common-module
+	implementation project(":common_module")
+
 	//spring boot
 	implementation 'org.springframework.boot:spring-boot-starter-web'
 
-	//mongo db
+	//db - mongo
 	implementation('org.springframework.boot:spring-boot-starter-data-mongodb')
 
+	//db - postgresql
+	implementation group: 'org.postgresql', name: 'postgresql', version: '42.7.3'
+	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+
 	//test
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 	testRuntimeOnly 'org.junit.platform:junit-platform-launcher'

src/backend/history_server/settings.gradle

@@ -1 +1,4 @@
 rootProject.name = 'history_server'
+
+include(":common_module")
+findProject(":common_module")?.projectDir = file("../common_module")

src/backend/history_server/src/main/java/com/jootalkpia/history_server/HistoryServerApplication.java

@@ -5,7 +5,11 @@
 import org.springframework.data.mongodb.config.EnableMongoAuditing;
 
 @EnableMongoAuditing
-@SpringBootApplication
+@SpringBootApplication(scanBasePackages = {
+		"com.jootalkpia.history_server",
+		"com.jootalkpia.passport",
+		"com.jootalkpia.config",
+})
 public class HistoryServerApplication {
 
 	public static void main(String[] args) {

src/backend/history_server/src/main/java/com/jootalkpia/history_server/controller/HistoryController.java

@@ -0,0 +1,31 @@
+package com.jootalkpia.history_server.controller;
+
+import com.jootalkpia.history_server.dto.ChatMessagePageResponse;
+import com.jootalkpia.history_server.service.HistoryQueryService;
+import com.jootalkpia.passport.anotation.CurrentUser;
+import com.jootalkpia.passport.component.UserInfo;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+public class HistoryController {
+
+    private static final String DEFAULT_PAGE_SIZE = "30";
+    private final HistoryQueryService historyQueryService;
+
+    @GetMapping("/api/v1/history/{channelId}")
+    public ChatMessagePageResponse getChatMessagesForward(
+            @PathVariable Long channelId,
+            //처음 요청시엔 서버 내에서 안읽은 메세지 값으로 설정하기 위해 false
+            // 이때 message의 objectId가 아닌 threadId가 기준
+            @RequestParam(required = false) Long cursorId,
+            @RequestParam(defaultValue = DEFAULT_PAGE_SIZE) int size,
+            @CurrentUser UserInfo userInfo) {
+        return historyQueryService.
+                getChatMessagesForward(channelId, cursorId, size, userInfo.userId());
+    }
+}

src/backend/history_server/src/main/java/com/jootalkpia/history_server/domain/BaseTimeEntity.java

@@ -1,5 +1,6 @@
 package com.jootalkpia.history_server.domain;
 
+import jakarta.persistence.Column;
 import java.time.LocalDateTime;
 import lombok.Getter;
 import org.springframework.data.annotation.CreatedDate;
@@ -9,6 +10,7 @@
 public abstract class BaseTimeEntity {
 
     @CreatedDate
+    @Column(updatable = false)
     private LocalDateTime createdAt; // 생성 시간
 
     @LastModifiedDate

src/backend/history_server/src/main/java/com/jootalkpia/history_server/domain/UserChannel.java

@@ -0,0 +1,26 @@
+package com.jootalkpia.history_server.domain;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Entity
+@Table(name = "user_channel")
+@Getter
+@RequiredArgsConstructor
+public class UserChannel extends BaseTimeEntity {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long userChannelId;
+
+    private Long userId;
+
+    private Long lastReadId;
+
+    private Long channelId;
+}

src/backend/history_server/src/main/java/com/jootalkpia/history_server/dto/ChatMessagePageResponse.java

@@ -0,0 +1,10 @@
+package com.jootalkpia.history_server.dto;
+
+import java.util.List;
+
+public record ChatMessagePageResponse(
+        boolean hasNext,
+        Long lastCursorId,
+        List<ThreadDto> threads
+) {}
+

src/backend/history_server/src/main/java/com/jootalkpia/history_server/dto/MessageDto.java

@@ -1,7 +1,9 @@
 package com.jootalkpia.history_server.dto;
 
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.jootalkpia.history_server.domain.Message;
 
+@JsonInclude(JsonInclude.Include.NON_NULL)
 public record MessageDto(
         String type,
         String text,
@@ -24,5 +26,17 @@ public Message toMessage() {
                 .videoUrl(this.videoUrl)
                 .build();
     }
+    public static MessageDto documentToDto(Message message) {
+        return new MessageDto(
+                message.getType(),
+                message.getText(),
+                message.getImageId(),
+                message.getImageUrl(),
+                message.getVideoId(),
+                message.getVideoThumbnailId(),
+                message.getThumbnailUrl(),
+                message.getVideoUrl()
+        );
+    }
 }
 

src/backend/history_server/src/main/java/com/jootalkpia/history_server/dto/ThreadDto.java

@@ -0,0 +1,30 @@
+package com.jootalkpia.history_server.dto;
+
+import com.jootalkpia.history_server.domain.ChatMessage;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public record ThreadDto(
+        Long channelId,
+        Long threadId,
+        String threadDateTime,
+        Long userId,
+        String userNickname,
+        String userProfileImage,
+        List<MessageDto> messages
+) {
+    public static ThreadDto from(ChatMessage chatMessage) {
+        return new ThreadDto(
+                chatMessage.getChannelId(),
+                chatMessage.getThreadId(),
+                chatMessage.getThreadDateTime(),
+                chatMessage.getUserId(),
+                chatMessage.getUserNickname(),
+                chatMessage.getUserProfileImage(),
+                chatMessage.getMessages().stream()
+                        .map(MessageDto::documentToDto)  // Message 변환
+                        .collect(Collectors.toList())
+        );
+    }
+}
+

src/backend/history_server/src/main/java/com/jootalkpia/history_server/repository/ChatMessageRepository.java

@@ -1,7 +1,14 @@
 package com.jootalkpia.history_server.repository;
 
 import com.jootalkpia.history_server.domain.ChatMessage;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.mongodb.repository.MongoRepository;
+import org.springframework.stereotype.Repository;
 
-public interface ChatMessageRepository extends MongoRepository<ChatMessage,String> {
+import java.util.List;
+
+@Repository
+public interface ChatMessageRepository extends MongoRepository<ChatMessage, String> {
+    // cursorId 이후의 메시지 조회 (페이징)
+    List<ChatMessage> findByChannelIdAndThreadIdGreaterThanOrderByThreadIdAsc(Long channelId, Long threadId, Pageable pageable);
 }

src/backend/history_server/src/main/java/com/jootalkpia/history_server/repository/UserChannelRepository.java

@@ -0,0 +1,14 @@
+package com.jootalkpia.history_server.repository;
+
+import com.jootalkpia.history_server.domain.UserChannel;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface UserChannelRepository extends JpaRepository<UserChannel, Long> {
+
+    @Query("SELECT u.lastReadId FROM UserChannel u WHERE u.userId = :userId AND u.channelId = :channelId")
+    Long findLastReadIdByUserIdAndChannelId(@Param("userId") Long userId, @Param("channelId") Long channelId);
+}

src/backend/history_server/src/main/java/com/jootalkpia/history_server/service/HistoryQueryService.java

@@ -0,0 +1,86 @@
+package com.jootalkpia.history_server.service;
+
+import com.jootalkpia.history_server.domain.ChatMessage;
+import com.jootalkpia.history_server.dto.ThreadDto;
+import com.jootalkpia.history_server.dto.ChatMessagePageResponse;
+import com.jootalkpia.history_server.repository.ChatMessageRepository;
+import com.jootalkpia.history_server.repository.UserChannelRepository;
+import java.util.Collections;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class HistoryQueryService {
+
+    private final ChatMessageRepository chatMessageRepository;
+    private final UserChannelRepository userChannelRepository;
+
+    public ChatMessagePageResponse getChatMessagesForward(Long channelId, Long cursorId, int size, Long userId) {
+        List<ChatMessage> chatMessageList = fetchMessagesForward(channelId, cursorId, size, userId);
+
+        if (chatMessageList.isEmpty()) {
+            return new ChatMessagePageResponse(false, null, Collections.emptyList());
+        }
+
+        List<ThreadDto> responseMessages = convertToDtoList(chatMessageList);
+        boolean hasNext = determineHasNext(responseMessages, size);
+
+        // size + 1로 조회했으므로, 초과한 1개 데이터 제거
+        if (hasNext) {
+            responseMessages = responseMessages.subList(0, size);
+        }
+
+        Long lastThreadId = getLastThreadId(responseMessages);
+
+        return new ChatMessagePageResponse(hasNext, lastThreadId, responseMessages);
+    }
+
+
+    /**
+     * DB에서 채팅 메시지를 조회하는 메서드
+     */
+    private List<ChatMessage> fetchMessagesForward(Long channelId, Long cursorId, int size, Long userId) {
+        if (cursorId == null) {
+            Long lastReadId = userChannelRepository.findLastReadIdByUserIdAndChannelId(userId, channelId);
+
+            if (lastReadId == null) {
+                return Collections.emptyList();  // 첫 입장 시 빈 응답
+            }
+
+            return chatMessageRepository.findByChannelIdAndThreadIdGreaterThanOrderByThreadIdAsc(
+                    channelId, lastReadId, PageRequest.of(0, size + 1));
+        }
+
+        return chatMessageRepository.findByChannelIdAndThreadIdGreaterThanOrderByThreadIdAsc(
+                channelId, cursorId, PageRequest.of(0, size + 1));
+    }
+
+    /**
+     * ChatMessage 리스트를 ChatMessageDto 리스트로 변환하는 메서드
+     */
+    private List<ThreadDto> convertToDtoList(List<ChatMessage> chatMessageList) {
+        return chatMessageList.stream()
+                .map(ThreadDto::from)
+                .toList();
+    }
+
+    /**
+     * hasNext(다음 페이지 여부)를 판별하는 메서드
+     */
+    private boolean determineHasNext(List<ThreadDto> responseMessages, int size) {
+        return responseMessages.size() > size;
+    }
+
+    /**
+     * 마지막 threadId를 반환하는 메서드
+     */
+    private Long getLastThreadId(List<ThreadDto> responseMessages) {
+        if (responseMessages.isEmpty()) {
+            return null;
+        }
+        return responseMessages.get(responseMessages.size() - 1).threadId();
+    }
+}

src/backend/history_server/src/main/resources/application.yml

@@ -1,4 +1,19 @@
 spring:
+  datasource:
+    driver-class-name: org.postgresql.Driver
+    url: jdbc:postgresql://${DB_HOST}:${DB_PORT}/${DB_NAME}
+    username: ${DB_USER}
+    password: ${DB_PASSWORD}
+
+  jpa:
+    show-sql: true
+    hibernate:
+      ddl-auto: none
+    properties:
+      hibernate:
+        format_sql: true
+        show_sql: true
+
   data:
     mongodb:
       uri: ${MONGO_URI}