Spring Websocket Session集群

WebSocketSession无法序列化到redis，因此在集群中，我们无法将所有WebSocketSession都缓存到redis进行session共享。但是，我们可以使用redis的发布订阅模式解决。

1、WebSocketHandler 消息处理器

import com.alibaba.fastjson.JSON;
import com.techhf.common.core.constant.SecurityConstants;
import com.techhf.common.core.exception.BusinessServiceException;
import com.techhf.im.api.model.vo.ChatPageVO;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * websocket 消息处理器
 *
 * @author ronshi
 * @date 2022/11/18 9:17
 */
@Slf4j
@Component
public class WebSocketHandler extends TextWebSocketHandler {
    /**
     * 冒号分隔符
     */
    public static final String SEMICOLON = ":";
    /**
     * redis 订阅通道名
     */
    public static final String CHANNEL_NAME = "imRedisTopic";
    /**
     * 当前节点在线session
     */
    public static final Map POOL_SESSION = new ConcurrentHashMap<>();

    @Autowired
    private RedisTemplate redisTemplate;


    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        String key = getKey(session);
        POOL_SESSION.put(key, session);
    }

    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
        String key = getKey(session);
        POOL_SESSION.remove(key);
    }

    private String getKey(WebSocketSession session) {
        String userType = (String) session.getAttributes().get(SecurityConstants.DETAILS_USERTYPE);
        String userId = (String) session.getAttributes().get(SecurityConstants.DETAILS_USER_ID);
        String key = userType + SEMICOLON + userId;
        if (userId == null) {
            throw new BusinessServiceException("未认证");
        }
        return key;
    }

    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        // 获得客户端传来的消息
        String payload = message.getPayload();
        //log.info("server 接收到消息 {}", payload);
        session.sendMessage(new TextMessage(payload));
    }

    /**
     * 发送消息
     */
    public boolean sendMsg(ChatPageVO message) {
        String key = message.getAnotherUserType() + SEMICOLON + message.getAnotherUserId();
        if (POOL_SESSION.containsKey(key)) {
            try {
                POOL_SESSION.get(key).sendMessage(new TextMessage(JSON.toJSONString(message)));
            } catch (IOException e) {
                log.error("发送消息给{}失败", key, e);
                return false;
            }
        } else {
            // 发布消息
            redisTemplate.convertAndSend(CHANNEL_NAME, JSON.toJSONString(message));
        }
        return true;
    }


}

2、RedisMessageListener 订阅发布监听类

import com.alibaba.fastjson.JSON;
import com.techhf.im.api.model.vo.ChatPageVO;
import com.techhf.im.biz.ws.WebSocketHandler;
import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Map;

/**
 * Redis订阅发布监听类
 *
 * @author ronshi
 * @date 2023/6/7 16:00
 */
@Slf4j
@Component
public class RedisMessageListener implements MessageListener {
    @Resource
    private RedisTemplate redisTemplate;

    @Override
    public void onMessage(Message message, byte[] bytes) {
        // 获取消息
        Object messageBody = redisTemplate.getValueSerializer().deserialize(message.getBody());
        if (messageBody == null) {
            return;
        }
        String content = messageBody.toString();
        ChatPageVO chatMessage = JSON.parseObject(content, ChatPageVO.class);
        String key = chatMessage.getAnotherUserType() + WebSocketHandler.SEMICOLON + chatMessage.getAnotherUserId();
        //当前节点在线session
        Map onlineSessionMap = WebSocketHandler.POOL_SESSION;
        if (onlineSessionMap.containsKey(key)) {
            try {
                onlineSessionMap.get(key).sendMessage(new TextMessage(content));
            } catch (IOException e) {
                log.error("发送消息给{}失败", key, e);
            }
        }
    }
}

3、RedisSubscriberConfig 订阅发布模式的容器配置

import com.techhf.im.biz.ws.WebSocketHandler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.listener.ChannelTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;

/**
 * 订阅发布模式的容器配置
 *
 * @author ronshi
 * @date 2023/6/7 17:01
 */
@Configuration
@AutoConfigureAfter({RedisMessageListener.class})
public class RedisSubscriberConfig {
    @Autowired
    private RedisMessageListener listener;

    /**
     * 创建消息监听容器
     *
     * @param redisConnectionFactory redis连接工厂
     * @return 监听容器
     */
    @Bean
    public RedisMessageListenerContainer getRedisMessageListenerContainer(RedisConnectionFactory redisConnectionFactory) {
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(redisConnectionFactory);
        container.addMessageListener(listener, new ChannelTopic(WebSocketHandler.CHANNEL_NAME));
        return container;
    }
}