cn.herodotus.stirrup.message.websocket.servlet.sender.WebSocketMessagingTemplate Maven / Gradle / Ivy

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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2020-2030 郑庚伟 ZHENGGENGWEI (码匠君),  Licensed under the AGPL License
 *
 * This file is part of Herodotus Stirrup.
 *
 * Herodotus Stirrup is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Herodotus Stirrup is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see .
 */

package cn.herodotus.stirrup.message.websocket.servlet.sender;

import cn.herodotus.stirrup.message.websocket.servlet.definition.WebSocketMessageSender;
import org.apache.commons.lang3.ObjectUtils;
import org.springframework.messaging.simp.SimpMessagingTemplate;
import org.springframework.messaging.simp.user.SimpUser;
import org.springframework.messaging.simp.user.SimpUserRegistry;

/**
 * Description: WebSocket 消息发送模版 
 * 
 * 单独抽取一个 MessagingTemplate 用作 WebSocket 消息发送的基本操作类。
 * {@link MultipleInstanceMessageSender}、{@link SingleInstanceMessageSender} 和 {@link MultipleInstanceMessageSyncConsumer} 三个类均使用该类进行基础操作。
 * 这样做的原因是多实例情况下还包含消息的同步，发送消息同步的实例既是同步消息的生产者，又是消费者。如果统一使用 {@link WebSocketMessageSender} 注入的 Bean。就不好区分各种情况，就会出现发送同步消息，存在循环发送消息的风险。
 *
 * @author : gengwei.zheng
 * @date : 2023/10/26 23:26
 */
public record WebSocketMessagingTemplate(SimpMessagingTemplate simpMessagingTemplate,
                                         SimpUserRegistry simpUserRegistry) {

    /**
     * 发送 WebSocket 点对点消息。发送信息给指定用户
     *
     * @param user        用户唯一标识
     * @param destination 消息同奥
     * @param payload     消息内容
     */
    public void pointToPoint(String user, String destination, Object payload) {
        if (isUserExist(user)) {
            simpMessagingTemplate.convertAndSendToUser(user, destination, payload);
        }
    }

    /**
     * 发送 WebSocket 广播消息。发送全员信息
     *
     * @param destination 消息同奥
     * @param payload     消息内容
     */
    public void broadcast(String destination, Object payload) {
        simpMessagingTemplate.convertAndSend(destination, payload);
    }

    /**
     * 根据用户 ID 获取到对应的 WebSocket 用户
     *
     * @param userId 系统用户ID
     * @return WebSocket 用户 {@link SimpUser}
     */
    public SimpUser getUser(String userId) {
        return simpUserRegistry.getUser(userId);
    }

    /**
     * 判断 WebSocket用户是否存在。
     * 
     * 注意：只能查询到当前所在 WebSocket实例中的实时 WebSocket 用户信息。如果实时用户在不同的实例中，则查询不到。
     *
     * @param userId 用户ID
     * @return true 用户存在，false 用户不存在
     */
    public boolean isUserExist(String userId) {
        return ObjectUtils.isNotEmpty(getUser(userId));
    }
}