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QT之QLocalSocket下的两进程互相守护

news 2025/8/5 9:34:55

在Qt应用程序开发中，进程间通信（IPC）是一个常见的需求。QLocalSocket是Qt提供的一个强大的本地套接字类，它通过基于套接字的接口，使多个进程能够无缝交换数据，非常适合需要本地通信的场景。专门用于同一台机器上不同进程之间的高效通信。与传统的TCP/UDP网络套接字不同，QLocalSocket使用本地套接字（在Unix系统上通常是Unix域套接字，在Windows上是命名管道），提供了更高的性能和更低的延迟。

一、QLocalSocket的特点

优势

高性能: 本地通信避免了网络协议栈的开销
安全性: 通信仅限于本机，不会暴露到网络
简单易用: API设计与QTcpSocket类似，学习成本低
跨平台: 在不同操作系统上提供一致的接口

适用场景

主进程与子进程之间的数据交换
多个独立应用程序之间的协作
客户端-服务器架构的本地应用
进程间状态同步和事件通知

基本概念

QLocalSocket通常与QLocalServer配对使用：

QLocalServer: 作为服务器端，监听连接请求
QLocalSocket: 作为客户端，连接到服务器

二、两进程互相守护示例

1、简述

因为这个守护逻辑可以抽象成一个独立类GuardianService，只需传入：

本进程名称（或 socket 名）
对方进程名称
对方启动路径（用于崩溃后重启）

2、源码示例

// GuardianService.h
#ifndef GUARDIANSERVICE_H
#define GUARDIANSERVICE_H#include <QObject>
#include <QLocalServer>
#include <QLocalSocket>
#include <QTimer>
#include <QProcess>
#include <QDebug>class GuardianService : public QObject {Q_OBJECT
public:static GuardianService* init(const QString &selfSocketName,const QString &peerSocketName,const QString &peerExecutablePath,QObject *parent = nullptr);private:explicit GuardianService(const QString &selfName,const QString &peerName,const QString &peerPath,QObject *parent = nullptr);void start();void setupServer();void connectToPeer();void tryRestartPeer();private slots:void onNewConnection();void onHeartbeatReceived();void onHeartbeatTimeout();void onPeerDisconnected();private:QString selfSocket;QString peerSocket;QString peerPath;QLocalServer server;QLocalSocket *peerClientSocket;QTimer heartbeatSendTimer;QTimer heartbeatTimeoutTimer;
};#endif // GUARDIANSERVICE_H// GuardianService.cpp
#include "GuardianService.h"GuardianService* GuardianService::init(const QString &selfSocketName,const QString &peerSocketName,const QString &peerExecutablePath,QObject *parent) {GuardianService *service = new GuardianService(selfSocketName, peerSocketName, peerExecutablePath, parent);service->start();return service;
}GuardianService::GuardianService(const QString &selfName,const QString &peerName,const QString &peerPath,QObject *parent): QObject(parent),selfSocket(selfName),peerSocket(peerName),peerPath(peerPath),peerClientSocket(new QLocalSocket(this)) {connect(&heartbeatSendTimer, &QTimer::timeout, this, [this]() {if (peerClientSocket->state() == QLocalSocket::ConnectedState) {peerClientSocket->write("ping");peerClientSocket->flush();}});connect(&heartbeatTimeoutTimer, &QTimer::timeout, this, &GuardianService::onHeartbeatTimeout);connect(peerClientSocket, &QLocalSocket::disconnected, this, &GuardianService::onPeerDisconnected);
}void GuardianService::start() {setupServer();connectToPeer();heartbeatSendTimer.start(2000);     // 每2秒发送心跳heartbeatTimeoutTimer.start(5000);  // 最多5秒无回应
}void GuardianService::setupServer() {QLocalServer::removeServer(selfSocket);if (!server.listen(selfSocket)) {qWarning() << "[Guardian] Failed to listen on socket:" << selfSocket << server.errorString();return;}connect(&server, &QLocalServer::newConnection, this, &GuardianService::onNewConnection);
}void GuardianService::connectToPeer() {if (peerClientSocket->state() != QLocalSocket::UnconnectedState)peerClientSocket->abort();peerClientSocket->connectToServer(peerSocket);
}void GuardianService::onNewConnection() {QLocalSocket *incoming = server.nextPendingConnection();connect(incoming, &QLocalSocket::readyRead, this, &GuardianService::onHeartbeatReceived);connect(incoming, &QLocalSocket::disconnected, incoming, &QLocalSocket::deleteLater);
}void GuardianService::onHeartbeatReceived() {heartbeatTimeoutTimer.start(5000);  // 重置超时计时器QLocalSocket *sender = qobject_cast<QLocalSocket *>(sender());if (sender) sender->readAll();
}void GuardianService::onHeartbeatTimeout() {qWarning() << "[Guardian] Peer timeout, attempting restart...";tryRestartPeer();
}void GuardianService::onPeerDisconnected() {qWarning() << "[Guardian] Disconnected from peer. Reconnecting...";connectToPeer();
}void GuardianService::tryRestartPeer() {QProcess::startDetached(peerPath);heartbeatTimeoutTimer.start(5000); // 等待新实例心跳
}