세션 관리

@Configuration
public class EgovChatMemoryConfig {

    @Value("${chat.memory.max-messages:20}")
    private int maxMessages;

    @Bean
    public ChatMemory chatMemory(EgovRedisChatMemoryRepository repository) {
        return MessageWindowChatMemory.builder()
                .chatMemoryRepository(repository)  // Redis 기반 저장소
                .maxMessages(maxMessages)          // 최대 20개 메시지
                .build();
    }

    @Bean
    public MessageChatMemoryAdvisor messageChatMemoryAdvisor(ChatMemory chatMemory) {
        return MessageChatMemoryAdvisor.builder(chatMemory).build();
    }
}

public class SessionContext {

    private static final ThreadLocal<String> CURRENT_SESSION_ID = new ThreadLocal<>();

    // Controller에서 호출 - 세션 ID 설정
    public static void setCurrentSessionId(String sessionId) {
        CURRENT_SESSION_ID.set(sessionId);
    }

    // Service에서 호출 - 세션 ID 조회
    public static String getCurrentSessionId() {
        String sessionId = CURRENT_SESSION_ID.get();
        return sessionId != null ? sessionId : "default";
    }

    // 스트리밍 완료 후 호출 - 메모리 정리
    public static void clear() {
        CURRENT_SESSION_ID.remove();
    }
}

@Slf4j
@Component
public class EgovRedisChatMemoryRepository implements ChatMemoryRepository {

    private final RedisTemplate<String, Object> redisTemplate;
    private final ObjectMapper objectMapper;

    private static final String CHAT_MEMORY_KEY_PREFIX = "chat:memory:";

    /**
     * 메시지 저장
     * Spring AI Message 객체 -> Map -> JSON -> Redis
     */
    @Override
    public void saveAll(String conversationId, List<Message> messages) {
        String key = CHAT_MEMORY_KEY_PREFIX + conversationId;

        // Message 객체를 Map으로 변환
        List<Map<String, Object>> simpleMessages = messages.stream()
            .map(this::messageToMap)
            .collect(Collectors.toList());

        String messagesJson = objectMapper.writeValueAsString(simpleMessages);
        redisTemplate.opsForValue().set(key, messagesJson);
    }

    /**
     * 메시지 조회
     * Redis JSON -> Map 리스트 -> Spring AI Message 객체
     */
    @Override
    public List<Message> findByConversationId(String conversationId) {
        String key = CHAT_MEMORY_KEY_PREFIX + conversationId;
        Object value = redisTemplate.opsForValue().get(key);

        if (value == null) return new ArrayList<>();

        List<Map<String, Object>> simpleMaps = objectMapper.readValue(
            value.toString(),
            new TypeReference<List<Map<String, Object>>>() {}
        );

        return simpleMaps.stream()
            .map(this::mapToMessage)
            .filter(Objects::nonNull)
            .collect(Collectors.toList());
    }

    private Map<String, Object> messageToMap(Message message) {
        Map<String, Object> map = new HashMap<>();
        map.put("messageType", message.getMessageType().name());

        if (message instanceof UserMessage) {
            map.put("content", ((UserMessage) message).getText());
        } else if (message instanceof AssistantMessage) {
            map.put("content", ((AssistantMessage) message).getText());
        } else if (message instanceof SystemMessage) {
            map.put("content", ((SystemMessage) message).getText());
        }
        return map;
    }

    private Message mapToMessage(Map<String, Object> map) {
        String messageType = (String) map.get("messageType");
        String content = (String) map.get("content");

        return switch (messageType) {
            case "USER" -> new UserMessage(content);
            case "ASSISTANT" -> new AssistantMessage(content);
            case "SYSTEM" -> new SystemMessage(content);
            default -> null;
        };
    }
}

chat:
  memory:
    max-messages: 20                # 최대 대화 히스토리