如何在Qt中轻松建立SSH连接？

Question

我正在寻找一种在 Qt 中建立 ssh 连接的简单方法，类似于我在 Java 中的操作方式。

例如，要通过 java 登录 ssh 连接，我可以这样做：

import com.sshtools.j2ssh.SshClient;
import com.sshtools.j2ssh.transport.IgnoreHostKeyVerification;
import com.sshtools.j2ssh.authentication.PasswordAuthenticationClient;
import com.sshtools.j2ssh.authentication.AuthenticationProtocolState;

 ......

    SshClient ssh = new SshClient();
    try {
        // Timeout of ten seconds
        ssh.setSocketTimeout(10*1000);
        ssh.connect(ip, port, new IgnoreHostKeyVerification());

        PasswordAuthenticationClient auth = new PasswordAuthenticationClient();
        auth.setUsername(username);
        auth.setPassword(password);

        if (ssh.authenticate(auth) != AuthenticationProtocolState.COMPLETE) {
            errorLabel.setForeground(Color.RED);
            errorLabel.setText("Username or password is incorrect");
        }
        else
            successful = true;
    }
    catch (Exception e) {
        errorLabel.setForeground(Color.RED);
        errorLabel.setText("Cannot log into website");
        e.printStackTrace();
    }

我见过的 Qt 解决方案是：

1. 使用 libssh 自行部署
2. 使用 libssh2 自行部署
3. 使用 QProcess 调用外部 SSH 进程来建立
4. 连接库在这里： http://netsieben.com/products/ssh/

因为 Java 版本是免费的，我有点舍不得在这上面花钱，但如果必须的话，我也必须这么做。我不想自己推出，因为我只能看到这是错误的原因（除非这些库很容易使用？）。

有什么我没发现的吗？

编辑：我现在花了几天时间与 libssh 和 libqxt 进行斗争。据我所知，两者在 Windows 上都是完全失败的。即使按照此处描述的步骤操作，Libqxt 也不会在使用 ssh 的 Windows 上进行编译 和此处。 Libssh 的 C++ 包装类包含标头中的所有内容，如果不仔细管理，这会导致链接失败。一旦这些链接器问题得到解决，Libssh 的编译库就会使 CDB 崩溃，因此无论是否使用 c++ 包装器，都无法使用 libssh 进行调试。所以现在我又回到了 libssh2 或者通过一些可疑的程序来支付它，而这些程序显然已经四年没有更新了。 Cryptlib，也许吧？大多数 qt 论坛帮助似乎是“生成另一个进程”，因此要求我的用户安装 ssh，这对 Windows 上的课程来说绝对不符合标准。

Answer 1

这是一个异步 ssh & scp“socket”是我为Qt编写的跨平台的。这需要 libSSH 并且并不完美（隐藏 rsa 密钥传递内容，以单次方式而不是通过 read 信号传递命令响应），但它很可能会满足您的需求。为了使其适用于 Windows，此文件必须是项目中包含的第一个文件（以便 qt 在导入正确的 Windows 套接字代码之前不会尝试导入 windows.h）。

标题：

#ifndef QSSHSOCKET_H
#define QSSHSOCKET_H

#include <libssh/libssh.h>
#include <QByteArray>
#include <QThread>
#include <QVector>
#include <QFile>
#include <sys/stat.h>
#include <sys/types.h>
#include <QDebug>

class QSshSocket: public QThread
{
    Q_OBJECT
public:

    enum SshError
    {
        /*! \brief There was trouble creating a socket. This was most likely due to the lack of an internet connection.*/
        SocketError,
        /*! \brief The ssh session could not be created due to inability to find the remote host.*/
        SessionCreationError,
        /*! \brief An ssh channel could not be created for the previous operation.*/
        ChannelCreationError,
        /*! \brief An scp channel could not be created for the previous file transfer operation.*/
        ScpChannelCreationError,
        /*! \brief There was an error requesting a pull file transfer.*/
        ScpPullRequestError,
        /*! \brief There was an error requesting a push file transfer.*/
        ScpPushRequestError,
        /*! \brief The destination file for the previous transfer does not exist.*/
        ScpFileNotCreatedError,
        /*! \brief There was an error reading a remote file. This could possibly be due to user permissions.*/
        ScpReadError,
        /*! \brief There was an error writing to a remote file. This could possibly be due to user permissions.*/
        ScpWriteError,
        /*! \brief The credentials of a user on the remote host could not be authenticated.*/
        PasswordAuthenticationFailedError
    };

    /*!
        \param position The center position of the box.
        \param size The size of the box.
        \brief The constructor.
    */
    explicit QSshSocket(QObject * parent = 0);

    /*!
        \brief The deconstructor.
    */
    ~QSshSocket();

    /*!
        \param host The hostname to establish an ssh connection with.
        \param port The port to establish an ssh connection over.
        \brief This function connects this socket to the specified host over the specified port. On success, the signal connected is emitted while error is emmited on failure.
    */
    void connectToHost(QString host, int port =22);

    /*!
        \brief This function disconnects the socket from the current host (if there is one. On success, the signal disconnected is emitted while error is emmited on failure.
    */
    void disconnectFromHost();

    /*!
        \param command The command to be executed.
        \brief This function executes a remote command on the connected host. If not connected to a remote host, the command is not executed.
        On success, the signal commandExecuted is emitted while error is emmited on failure.
    */
    void executeCommand(QString command);

    /*!
        \brief Returns the hostname of the remote machine this socket is connected to. If not connected to a remote host, this returns "".
    */
    QString host();

    /*!
        \brief Returns whether or not a user has been logged in at remote host.
    */
    bool isLoggedIn();

    /*!
        \brief Returns whether or not this socket is currently connected to a remote host.
    */
    bool isConnected();

    /*!
        \param user The username to login with.
        \param password The password of the account for the specified username.
        \brief This function to login to the currently connected host given credentials.
        On success, the signal authenticated is emitted while error is emmited on failure.
    */
    void login(QString user, QString password);

    /*!
        \brief Returns the port of the current connection. If not connected to a remote host, this returns -1.
    */
    int port();

    /*!
        \param localPath A path to a file stored on the local machine.
        \param password A path to a file stored on the remote machine.
        \brief This function attempts to pull a remote file from the connected host to a local file. The local file does not need to be created beforehand.
        On success, the signal pullSuccessful is emitted while error is emmited on failure.
        If not connected to a remote host, or if the transfer was unsuccessful, the signal error is emitted.
    */
    void pullFile(QString localPath, QString remotePath);

    /*!
        \param localPath A path to a file stored on the local machine.
        \param password A path to a file stored on the remote machine.
        \brief This function attempts to pull a remote file from the connected host to a local file. The local file does not need to be created beforehand.
        On success, the signal pushSuccessful is emitted while error is emmited on failure.
        If not connected to a remote host, or if the transfer was unsuccessful, the signal error is emitted.
    */
    void pushFile(QString localPath, QString remotePath);

    /*!
        \param path A relative or absolute path to a directory on the remote host.
        \brief This function attempts to set the working directory of the connection to path and emits workingDirectorySet upon completion.
        If workingDirectorySet indicates no change in the working directory, the path could not be found.
        If not connected to a remote host the signal error will be emitted.
    */
    void setWorkingDirectory(QString path);

    /*!
        \brief Returns the username of the current authenticated user on the remote host. If not connected to a remote host, or if a user has not been authenticated this returns "".
    */
    QString user();



signals:

    /*!
        \brief This signal is emitted when remote host has been connected to."
    */
    void connected();

    /*!
        \brief This signal is emitted when this class has been properly disconnected from a remote host.
    */
    void disconnected();

    /*!
        \param error The type of error that occured.
        \brief This signal is emitted when an error occurs.
    */
    void error(QSshSocket::SshError error);

    /*!
        \param command The command that was executed on the remote host.
        \param response The response to the command that was executed.
        \brief This signal is emitted when a response from the remote host is received regarding a command.
    */
    void commandExecuted(QString command,QString response);

    /*!
        \brief This signal is emitted when a user has been loggen in to the remote host."
    */
    void loginSuccessful();

    /*!
        \param localFile The path to a local file that the remote file was pulled to.
        \param remoteFile The path to a file pulled from the remote host.
        \brief This signal is emitted when a remote file is successfully transfered to a local file.
    */
    void pullSuccessful(QString localFile, QString remoteFile);

    /*!
        \param localFile The path to a local file pushed to the remote host.
        \param remoteFile The path to a remote file that the local file was pushed to.
        \brief This signal is emitted when a local file is successfully transfered to a remote file.
    */
    void pushSuccessful(QString localFile, QString remoteFile);

    /*!
        \param cwd The current working directory of the session on the remote host.
        \brief This signal is emitted when a current working directory is set.
    */
    void workingDirectorySet(QString cwd);

private slots:
    void run();

private:

    enum SSHOperationType
    {
        Command,
        WorkingDirectoryTest,
        Pull,
        Push
    };

    struct SSHOperation
    {
        SSHOperationType type;
        QString adminCommand,command, localPath, remotePath;
        bool executed;
    };

    int m_port;
    bool m_loggedIn ;
    QThread * m_thread;
    QString m_workingDirectory,m_nextWorkingDir,m_user, m_host,m_password;
    SSHOperation m_currentOperation;
    ssh_session m_session;
    bool m_connected,m_run;
};


#endif // QSSHSOCKET_H

来源：

#include "qsshsocket.h"
#include <QFileInfo>
// if compiling in windows, add needed flags.
#ifdef _WIN32
#   include <io.h>

typedef int mode_t;

/// @Note If STRICT_UGO_PERMISSIONS is not defined, then setting Read for any
///       of User, Group, or Other will set Read for User and setting Write
///       will set Write for User.  Otherwise, Read and Write for Group and
///       Other are ignored.
///
/// @Note For the POSIX modes that do not have a Windows equivalent, the modes
///       defined here use the POSIX values left shifted 16 bits.

static const mode_t S_ISUID      = 0x08000000;           ///< does nothing
static const mode_t S_ISGID      = 0x04000000;           ///< does nothing
static const mode_t S_ISVTX      = 0x02000000;           ///< does nothing
static const mode_t S_IRUSR      = mode_t(_S_IREAD);     ///< read by user
static const mode_t S_IWUSR      = mode_t(_S_IWRITE);    ///< write by user
static const mode_t S_IXUSR      = 0x00400000;           ///< does nothing
#   ifndef STRICT_UGO_PERMISSIONS
static const mode_t S_IRGRP      = mode_t(_S_IREAD);     ///< read by *USER*
static const mode_t S_IWGRP      = mode_t(_S_IWRITE);    ///< write by *USER*
static const mode_t S_IXGRP      = 0x00080000;           ///< does nothing
static const mode_t S_IROTH      = mode_t(_S_IREAD);     ///< read by *USER*
static const mode_t S_IWOTH      = mode_t(_S_IWRITE);    ///< write by *USER*
static const mode_t S_IXOTH      = 0x00010000;           ///< does nothing
#   else
static const mode_t S_IRGRP      = 0x00200000;           ///< does nothing
static const mode_t S_IWGRP      = 0x00100000;           ///< does nothing
static const mode_t S_IXGRP      = 0x00080000;           ///< does nothing
static const mode_t S_IROTH      = 0x00040000;           ///< does nothing
static const mode_t S_IWOTH      = 0x00020000;           ///< does nothing
static const mode_t S_IXOTH      = 0x00010000;           ///< does nothing
#   endif
static const mode_t MS_MODE_MASK = 0x0000ffff;           ///< low word
#endif


QSshSocket::QSshSocket(QObject * parent )
    :QThread(parent)
{
    m_host = "";
    m_user = "";
    m_password = "";
    m_port = -1;
    m_loggedIn = false;
    m_session  = NULL;
    m_workingDirectory = ".";

    qRegisterMetaType<QSshSocket::SshError>("QSshSocket::SshError");
    m_currentOperation.executed = true;

    m_run = true;
    start();
}

QSshSocket::~QSshSocket()
{
    m_run = false;
    this->wait();
}

void QSshSocket::run()
{

    while(m_run)
    {
        if (m_session == NULL)
        {
            if (m_host != "")
            {
                m_session = ssh_new();

                //set logging to verbose so all errors can be debugged if crash happens
                int verbosity = SSH_LOG_PROTOCOL;

                // set the pertinant ssh session options
                ssh_options_set(m_session, SSH_OPTIONS_HOST, m_host.toAscii().data());
                ssh_options_set(m_session, SSH_OPTIONS_USER, m_user.toAscii().data());
                ssh_options_set(m_session, SSH_OPTIONS_LOG_VERBOSITY, &verbosity);
                ssh_options_set(m_session, SSH_OPTIONS_PORT, &m_port);

                // try to connect given host, user, port
                int connectionResponse = ssh_connect(m_session);

                // if connection is Successful keep track of connection info.
                if (connectionResponse == SSH_OK)
                    connected();

                else
                    error(SessionCreationError);

            }

        }


        // if we have a vaild ssh connection, authenticate connection with credentials
        else if (!m_loggedIn)
        {


            // check to see if a username and a password have been given
            if (m_user != "" && m_password !="")
            {

                // try authenticating current user at remote host
                int worked = ssh_userauth_password(m_session, m_user.toAscii().data(), m_password.toAscii().data());


                // if successful, store user password.
                if (worked == SSH_OK)
                {
                    loginSuccessful();
                    m_loggedIn = true;
                }
                else
                {
                    m_user = "";
                    m_password = "";
                    error(PasswordAuthenticationFailedError);
                }


            }
        }
        // if all ssh setup has been completed, check to see if we have any commands to execute
        else if (!m_currentOperation.executed)
        {

            if (m_currentOperation.type == Command || m_currentOperation.type == WorkingDirectoryTest)
            {
                // attempt to open ssh shell channel
                ssh_channel channel = ssh_channel_new(m_session);

                // if attempt fails,return
                if (ssh_channel_open_session(channel) != SSH_OK)
                {
                    error(ChannelCreationError);
                }


                int requestResponse = SSH_AGAIN;

                // attempt to execute shell command
                while (requestResponse == SSH_AGAIN)
                    requestResponse = ssh_channel_request_exec(channel, m_currentOperation.adminCommand.toAscii().data());

                // if attempt not executed, close connection then return
                if (requestResponse != SSH_OK)
                {
                    error(ChannelCreationError);
                }


                QByteArray buffer;
                buffer.resize(1000);

                // read in command result
                int totalBytes = 0, newBytes = 0;
                do
                {
                    newBytes = ssh_channel_read(channel, &(buffer.data()[totalBytes]), buffer.size() - totalBytes, 0);
                    if (newBytes > 0)
                        totalBytes += newBytes;
                }while (newBytes > 0);

                // close channel
                ssh_channel_send_eof(channel);
                ssh_channel_close(channel);
                ssh_channel_free(channel);

                QString response = QString(buffer).mid(0,totalBytes);
                response.replace("\n","");
                if (m_currentOperation.type == WorkingDirectoryTest)
                {
                    if (response == "exists")
                        m_workingDirectory = m_nextWorkingDir;
                    m_nextWorkingDir = ".";
                    workingDirectorySet(m_workingDirectory);
                }
                else
                    commandExecuted( m_currentOperation.command, response) ;

            }
            // if all ssh setup has been completed, check to see if we have any file transfers to execute
            else if (m_currentOperation.type == Pull)
            {
                ssh_scp scpSession = ssh_scp_new(m_session,SSH_SCP_READ, m_currentOperation.remotePath.toAscii().data());
                if (scpSession == NULL)
                    error(ScpChannelCreationError);

                // attempt to initialize new scp session.
                int scpInitialized = ssh_scp_init(scpSession);
                if(scpInitialized != SSH_OK)
                {
                    ssh_scp_close(scpSession);
                    ssh_scp_free(scpSession);
                    error(ScpChannelCreationError);
                }


                // attempt to authorize new scp pull
                if (ssh_scp_pull_request(scpSession) != SSH_SCP_REQUEST_NEWFILE)
                {
                    ssh_scp_close(scpSession);
                    ssh_scp_free(scpSession);
                    error(ScpPullRequestError);
                }

                // accept authorization
                ssh_scp_accept_request(scpSession);


                // get remote file size
                int size = ssh_scp_request_get_size(scpSession);

                // resize buffer, read remote file into buffer
                QByteArray buffer;
                buffer.resize(size);

                // if an error happens while reading, close the scp session and return
                if (ssh_scp_read(scpSession, buffer.data() , size) == SSH_ERROR)
                {
                    ssh_scp_close(scpSession);
                    ssh_scp_free(scpSession);
                    error(ScpReadError);
                }

                // loop until eof flag
                if  (ssh_scp_pull_request(scpSession)  != SSH_SCP_REQUEST_EOF)
                {
                    ssh_scp_close(scpSession);
                    ssh_scp_free(scpSession);
                    error(ScpReadError);
                }

                //close scp session
                ssh_scp_close(scpSession);
                ssh_scp_free(scpSession);

                // open up local file and write contents of buffer to it.
                QFile file(m_currentOperation.localPath);
                file.open(QIODevice::WriteOnly);
                file.write(buffer);
                file.close();

                pullSuccessful(m_currentOperation.localPath,m_currentOperation.remotePath);

            }
            else if (m_currentOperation.type == Push)
            {
                // attempt to create new scp from ssh session.
                ssh_scp scpSession = ssh_scp_new(m_session,SSH_SCP_WRITE, m_currentOperation.remotePath.toAscii().data());

                // if creation failed, return
                if (scpSession == NULL)
                    error(SocketError);


                // attempt to initialize new scp session.
                int scpInitialized = ssh_scp_init(scpSession);


                // if failed, close scp session and return.
                if(scpInitialized != SSH_OK)
                {
                    ssh_scp_close(scpSession);
                    ssh_scp_free(scpSession);
                    error(ScpChannelCreationError);
                }


                // open the local file and check to make sure it exists
                // if not, close scp session and return.
                QFile file(m_currentOperation.localPath);
                if (!file.exists())
                {
                    ssh_scp_close(scpSession);
                    ssh_scp_free(scpSession);
                    error(ScpFileNotCreatedError);
                }

                // if the file does exist, read all contents as bytes
                file.open(QIODevice::ReadOnly);
                QByteArray buffer =file.readAll();
                file.close();

                // attempt to authorize pushing bytes over scp socket
                // if this fails, close scp session and return.
                if (ssh_scp_push_file(scpSession, m_currentOperation.remotePath.toAscii().data(), buffer.size(), S_IRUSR | S_IWUSR) != SSH_OK)
                {
                    ssh_scp_close(scpSession);
                    ssh_scp_free(scpSession);
                    error(ScpPushRequestError);
                }


                // once authorized to push bytes over scp socket, start writing
                // if an error is returned,  close scp session and return.
                if ( ssh_scp_write(scpSession,buffer.data(), buffer.size()) != SSH_OK)
                {

                    ssh_scp_close(scpSession);
                    ssh_scp_free(scpSession);
                    error(ScpWriteError);
                }


                // close scp session and return.
                ssh_scp_close(scpSession);
                ssh_scp_free(scpSession);

                pushSuccessful(m_currentOperation.localPath,m_currentOperation.remotePath);

            }


            m_currentOperation.executed = true;
        }
        else
        {
            msleep(100);
        }

    }

}
void QSshSocket::disconnectFromHost()
{
    m_host = "";
    m_user = "";
    m_password = "";
    m_port = -1;
    m_loggedIn = false;
    if (m_session != NULL)
    {
        ssh_disconnect(m_session);
        ssh_free(m_session);
    }
    m_session = NULL;
}

void QSshSocket::connectToHost(QString host, int port)
{
    m_host = host;
    m_port = port;
}
void QSshSocket::login(QString user, QString password)
{
    m_user = user;
    m_password = password;
}
void QSshSocket::executeCommand(QString command)
{
    m_currentOperation.type = Command;
    if (m_workingDirectory != ".")
        m_currentOperation.adminCommand = "cd " + m_workingDirectory + "; "  + command;
    else
        m_currentOperation.adminCommand = command ;

    m_currentOperation.command =command;
    m_currentOperation.executed = false;
}

void QSshSocket::pullFile(QString localPath, QString remotePath)
{
    m_currentOperation.localPath = localPath;
    if (QFileInfo(remotePath).isAbsolute())
        m_currentOperation.remotePath = remotePath;
    else
        m_currentOperation.remotePath = m_workingDirectory + "/" + remotePath;
    m_currentOperation.type = Pull;
    m_currentOperation.executed = false;
}

void QSshSocket::pushFile(QString localPath, QString remotePath)
{
    m_currentOperation.localPath = localPath;
    if (QFileInfo(remotePath).isAbsolute())
        m_currentOperation.remotePath = remotePath;
    else
        m_currentOperation.remotePath = m_workingDirectory + "/" + remotePath;
    m_currentOperation.type = Push;
    m_currentOperation.executed = false;
}

void QSshSocket::setWorkingDirectory(QString path)
{
    m_nextWorkingDir = path;
    m_currentOperation.type = WorkingDirectoryTest;
    m_currentOperation.adminCommand = "[ -d " + m_nextWorkingDir +" ] && echo 'exists'";
    m_currentOperation.executed = false;
}

bool QSshSocket::isConnected()
{
    return m_session != NULL;
}

bool QSshSocket::isLoggedIn()
{
    return m_loggedIn;
}

QString QSshSocket::user(){return m_user;}
QString QSshSocket::host(){return m_host;}
int QSshSocket::port(){return m_port;}

Answer 2

我花了几天时间寻找某种解决方案，然后忘记了这个问题。然后今天我在 Qt-Creator 源代码中偶然发现了这个小宝石 Utils::ssh，包括对 SFTP、普通 SSH 和各种好东西的支持。

从 Qt-Creator 中解开一些东西可能会很痛苦，但是经历了这个过程就相当于获取了 Botan（QT-Creator 中的其他库之一）+ Utils

Answer 3

请参阅 LibQxt。查找 QxtSsh 类。 hg repo 在内部使用 libssh2。

Answer 4

我正在使用 libssh2 http://www.libssh2.org/ 和 qt 。我以最简单的方式使用它 - 本机套接字。我没有时间将其转换为使用 qt 套接字。不过效果很好。
项目描述是：
http://www.chaosstuff.com /2013/09/gnome-mplayer-remote-with-qt-and-libssh2.html
源代码位于：
https://bitbucket.org/nchokoev/qtsshremote