使用 Qt 编写安全的服务器应用程序

Question

我已经按照教程“使用 Qt 编写安全服务器应用程序”（https://blog.quickmediasolutions.com/2012/09/18/writing-secure-server-applications-with-qt.html）但是我遇到了错误：

CSampleServer.h

#ifndef CSAMPLESERVER_H
#define CSAMPLESERVER_H

#include <QTcpServer>

class CSampleServer : public QTcpServer
{
public:
    CSampleServer();

private:
    void incomingConnection(int);

signals:
    void StatusMessage(QString);
};

#endif // CSAMPLESERVER_H

CSampleServer.cpp

#include "CSampleServer.h"
#include "CSecureSocket.h"

CSampleServer::CSampleServer()
{
}

void CSampleServer::incomingConnection(int handle)
{
    CSecureSocket * socket = new CSecureSocket(this);
    connect(socket, SIGNAL(StatusMessage(QString)), SIGNAL(StatusMessage(QString)));
    socket->Process(handle);
}

CSecureSocket.h

#ifndef CSECURESOCKET_H
#define CSECURESOCKET_H

#include <QSslSocket>

class CSecureSocket : public QSslSocket
{
public:
    CSecureSocket();
    void Process(int);


signals:
    void StatusMessage(QString);
};

#endif // CSECURESOCKET_H

CSecureSocket.cpp

#include "CSecureSocket.h"
#include <QHostAddress>

CSecureSocket::CSecureSocket()
{
}

void CSecureSocket::Process(int handle)
{
    /* Emit a message indicating the address of the client. */
    setSocketDescriptor(handle);
    emit StatusMessage(tr("Incoming connection from %1.").arg(peerAddress().toString()));

    /* Set the certificate and private key. */
    setLocalCertificate("server.crt");
    setPrivateKey("server.key.insecure");

    /* Start the server encryption process and wait for it to complete. */
    startServerEncryption();
    if(waitForEncrypted())
    {
        emit StatusMessage("Session with client is now encrypted.");

        /* Respond with a basic HTTP message. */
        write("HTTP/1.1 200 OK\r\n"
              "Content-type: text/plain\r\n"
              "Content-length: 12\r\n"
              "\r\n"
              "Hello World!");

        emit StatusMessage("Message sent to client. Closing connection.");
    }
    else
        emit StatusMessage(tr("An error occurred: %1.").arg(errorString()));

    /* Close the connection once the data is written. */
    disconnectFromHost();
}

MainWindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "CSampleServer.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:
    void OnStart();
    void OnStatusMessage(QString);

private:
    Ui::MainWindow *ui;
    CSampleServer m_server;
};

#endif // MAINWINDOW_H

MainWindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    connect(&m_server, SIGNAL(StatusMessage(QString)), SLOT(OnStatusMessage(QString)));
    connect(ui->pushButton, SIGNAL(clicked()), SLOT(OnStart()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::OnStart()
{
    quint16 port = ui->spinBox->value();
    if(m_server.listen(QHostAddress::Any, port))
        OnStatusMessage(tr("Listening on port %1...").arg(port));
    else
        OnStatusMessage(tr("Unable to listen on port %1.").arg(port));
}

void MainWindow::OnStatusMessage(QString message)
{
    ui->plainTextEdit->appendPlainText(message);
}

你能帮帮我吗？提前致谢！

Answer 1

1.void CSampleServer::incomingConnection(int handle) 参数应该是 qintptr 而不是 int。

2.connect(socket, SIGNAL(StatusMessage(QString)), SIGNAL(StatusMessage(QString)));声明错误的接收者对象在哪里

3.void CSecureSocket::Process(int handle) 使用 qintptr

4.正确阅读文档有更多错误

Answer 2

问题是没有为 CSampleServer 和 CSecureSocket 类生成 moc_* 文件。

要使该示例正常工作，您需要：

1. 将 Q_OBJECT 宏添加到 CSampleServer.h 和 CSecureSocket.h 类定义中
2. 清理项目
3. 运行 qmake 并确保 moc_* 文件在那里。
4. 再次构建项目，此时构建问题应该消失了。

Answer 3

您可以使用 SSL 创建安全服务器。这是一个使用 QSsLSocket 的示例服务器：

#include <QtNetwork>
#include <QMessageBox>

class server : public QTcpServer
{
    Q_OBJECT
public:
    explicit server(QObject *parent = 0);
    ~server();

    QSslSocket server_socket;

public slots:


      void tcpReady();

      void encrypted();

      void sslError( QList<QSslError> errors );

      bool start_listen(int port_no);

protected:
    void incomingConnection( int descriptor );

};

server::server(QObject *parent) :
    QTcpServer(parent)
{

    server_socket.setProtocol(QSsl::SslV3);

    QByteArray key;
    QByteArray cert;

    QFile file_key("server.key");
    if(file_key.open(QIODevice::ReadOnly))
    {
        key = file_key.readAll();
        file_key.close();
    }
    else
    {
        qDebug() << file_key.errorString();
    }

    QFile file_cert("server.crt");
    if(file_cert.open(QIODevice::ReadOnly))
    {
        cert = file_cert.readAll();
        file_cert.close();
    }
    else
    {
        qDebug() << file_cert.errorString();
    }


    QSslKey ssl_key(key, QSsl::Rsa,QSsl::Pem,QSsl::PrivateKey,"server");

    QSslCertificate ssl_cert(cert);

    server_socket.addCaCertificate(ssl_cert);
    server_socket.setLocalCertificate(ssl_cert);
    server_socket.setPrivateKey(ssl_key);


    connect( &server_socket, SIGNAL(sslErrors(QList<QSslError>)),
            this, SLOT(sslError(QList<QSslError>)) );

    connect(&server_socket,SIGNAL(encrypted()),this,SLOT(encrypted()));

    server_socket.setSocketOption(QAbstractSocket::KeepAliveOption, true );
}

server::~server()
{
    server_socket.disconnectFromHost();
    server_socket.waitForDisconnected();
}

void server::tcpReady()
{
    QByteArray array = server_socket.read( server_socket.bytesAvailable() );
    //...
}

void server::encrypted()
{
    connect( &server_socket, SIGNAL(readyRead()),
             this, SLOT(tcpReady()) );
    emit connection_established();
}

void server::sslError(QList<QSslError> errors)
{
    QString erroStr="";
    foreach (const QSslError &e, errors)
        erroStr.append(e.errorString()).append("\n");

    QMessageBox::warning( (QWidget *)this->parent(), tr("Error"),erroStr );

    server_socket.ignoreSslErrors();
}


bool server::start_listen(int port_no)
{
    if( !this->listen( QHostAddress::Any, port_no ) )
    {
        QMessageBox::warning( (QWidget *)this->parent(), tr("Error!"), tr("Cannot listen to port %1").arg(port_no) );

    }
    else
        return true;
}

void server::incomingConnection(int descriptor)
{
    if(server_socket.state()!=QAbstractSocket::UnconnectedState)
        return;
    if( !server_socket.setSocketDescriptor( descriptor ) )
    {
        QMessageBox::warning( (QWidget *)this->parent(), tr("Error!"), tr("Socket error!") );
        return;
    }
    else
    {
        server_socket.startServerEncryption();
    }
}

您应该为您的应用程序生成一个 server.key 和一个 server.crt 文件。

Answer 4

这种用法：

CSecureSocket * socket = new CSecureSocket(this);

与此声明/定义不兼容：

CSecureSocket();

试试：

CSecureSocket* socket = new CSecureSocket();

...