title: “ QTcpServer实现多客户端连接\t\t”
tags:
- qt
- socket
- tcp
url: 760.html
id: 760
categories: - Qt
date: 2017-12-21 21:35:50
介绍
QTcpServer使用请见:QTcpSocket-Qt使用Tcp通讯实现服务端和客户端 QTcpServer类默认提供的只有无参数的newConnection的信号,这样虽然知道有人连接了,并且可以通过nextPendingConnection获取连接的socket,但并不便于管理,尤其是在连接断开以后无法判断具体那个断开了,因为QTcpSocket只提供了无参的disconnected信号。。。 这样就算在newConnection是存储一个list或者map,也无法在disconnected是知道具体是那一项断开连接,给不同的QTcpSocket的信号指向不同的槽。 实际上socket有自己的句柄,并通过下述函数在初步连接时就赋予了对应的socketDescriptor
virtual void incomingConnection(qintptr socketDescriptor)
当有client连接时,首先是此方法被调用,可自行在此方法内建立QTcpSocket并将socketDescriptor值赋予socket,并在socket断开时告知此标识符
范例
源码请见GitHub:QtOtherModuleExamples tcp_server.h
ifndef TCP_SERVER_H
define TCP_SERVER_H
include
namespace tcp_server_private {
class TcpServerPrivate;
}
class QTcpSocket;
/**
- @brief Tcp多客户端服务器
/
class TcpServer : public QTcpServer {
Q_OBJECT
public:
/* - @brief 构造函数
- @param parent 父QObject
/
explicit TcpServer(QObject parent = Q_NULLPTR);
/** - @brief 析构函数
- 非多线程模式行为:关闭所有连接后析构
- 多线程模式行为:关闭所有连接及线程池后析构
/
~TcpServer();
signals:
/* - @brief 客户端连入
- @param 连接句柄
- @param socket指针
/
void ClientConnected(qintptr, QTcpSocket);//发送新用户连接信息
/** - @brief socket已断开连接
- 若需要在socket后析构后进行操作的可连接此信号
- @param 连接句柄
/
void ClientDisconnected(qintptr);
/* - @brief 主动断开连接信号
- 若服务端想要主动断开与客户端连接将会发出此信号
- 此信号发出这表明进行断开操作不表明断开成功,成功以SocketDisconnected信号为准
- @param 连接句柄
/
void InitiativeDisConnectClient(qintptr);
protected slots:
/* - @brief 客户端已断开槽
- 此槽与客户端的已断开信号连接
- @param handle
/
void ClientDisconnectedSlot(qintptr handle);
protected:
/* - @brief 重写-有连接到来
- 连接到来不一定连接,会根据maxPendingConnections决定是否连接
- @param handle 连接句柄
/
virtual void incomingConnection(qintptr handle);
private:
tcp_server_private::TcpServerPrivate private_;
};endif // TCP_SERVER_H
tcp_server.cpp
include “tcp_server.h”
include “tcp_server_private.h”
//构造函数
TcpServer::TcpServer(QObject parent)
: QTcpServer(parent),
private_(new tcp_server_private::TcpServerPrivate) {
}
//析构函数
TcpServer::~TcpServer() {
for(tcp_server_private::TcpSocket client : private->clients.values()) {
client->disconnectFromHost();
auto handle = client->socketDescriptor();
client->deleteLater();
//告知其他调用者 当前socket断开,避免有需要在socket后执行的方法
emit ClientDisconnected(handle);
}
if(private)
delete private;
this->close();
}
//重写-有连接到来
void TcpServer::incomingConnection(qintptr handle) {
//超出最大练级数量关闭连接
if (private->clients.size() > maxPendingConnections()) {
QTcpSocket tcp;
tcp.setSocketDescriptor(handle);
tcp.disconnectFromHost();
return;
}
auto clientsocket = new tcp_server_private::TcpSocket(handle);
Q_ASSERT(client_socket->socketDescriptor() == handle);
//socket断开连接的信号与server槽连接
connect(client_socket,
&tcp_server_private::TcpSocket::ClientDisconnected,
this,
&TcpServer::ClientDisconnectedSlot);
//主动断开连接的操作
connect(this,
&TcpServer::InitiativeDisConnectClient,
client_socket,
&tcp_server_private::TcpSocket::DisconnectSocket);
//map记录
private->clients.insert(handle, clientsocket);
qDebug()<
}
//客户端已断开槽
void TcpServer::ClientDisconnectedSlot(qintptr handle) {
//map中移除
private
qDebug()<
emit ClientDisconnected(handle);
}
private
ifndef TCP_SERVER_PRIVATE_H
define TCP_SERVER_PRIVATE_H
include
namespace tcp_server_private {
class TcpSocket : public QTcpSocket {
Q_OBJECT
public:
/**
- @brief 构造函数
- @param socketDescriptor 连接句柄
- @param parent 父QObject
/
TcpSocket(qintptr handle, QObject parent = 0);
signals:
/* - 已断开连接信号
/
void ClientDisconnected(qintptr);
public slots:
/* - @brief 断开连接
- @param handle 连接句柄
/
void DisconnectSocket(qintptr handle);
private:
qintptr handle_;
};
/* - @brief Tcp多客户端服务器私有类
/
class TcpServerPrivate {
public:
QMap<int, TcpSocket > clients; ///所有连接的map
};
}//tcp_server_privateendif // TCP_SERVER_PRIVATE_H
//cppinclude “tcp_server_private.h”
namespace tcpserver_private {
//构造函数
TcpSocket::TcpSocket(qintptr handle, QObject *parent)
: QTcpSocket(parent), handle(handle) {
this->setSocketDescriptor(handle);
//断开连接消息
connect(this,&TcpSocket::disconnected,
&{
this->deleteLater();
emit this->ClientDisconnected(handle);
});
}
//主动断开连接槽
void TcpSocket::DisconnectSocket(qintptr handle) {
if (handle == handle_)
disconnectFromHost();
}
}
- incomingConnection首先判断是否超出最大连接数量,超出就断开新链接,最大连接数量在maxPendingConnections方法获取,而当前已连接client在自定义server的TcpServerPrivate::clients这个QMap记录,此map记录了socketDescriptor和socket指针的映射关系
- 若未达最大连接数量,则连接创建新的tcpsocket,并将socketDescriptor赋值到socket对象,最后发出ClientConnected信号,此信号带有新链接的socket的指针,可以用于自定义收发信号槽。
- socket对象的disconnected信号直接connect到了lambda表达式以发出新的信号,新信号ClientDisconnected,并带有socketDescriptor句柄标识符,从而避免了socket断开连接后不知道具体哪个断开
- socket在创建时均吧ClientDisconnected信号与server的ClientDisconnectedSlot槽连接,当有连接断开时会动态维护map记录
- server析构时以disconnectFromHost方法主动断开和所有客户端连接,若需要等客户端先断开可以用waitForDisconnected
上述范例将TcpSocket定义在tcp_server_private命名空间不对外可见,且TcpServer返回值也是QTcpSocket,若需要继承QTcpSocket做更多自定义需要将TcpSocket移出