C++

Get Text Received on an SSH Channel

Demonstrates the Chilkat Ssh.GetReceivedText method, which decodes and returns all text currently accumulated in a channel's normal receive buffer. The first argument is the channel number and the second is the charset. The receive buffer is cleared after the text is returned.

Background: This is the retrieval half of the read-then-get pattern: a Channel* read or receive call fills the buffer, and this hands you the text. Because the buffer is cleared on retrieval, each call returns only what arrived since the last one. A valid channel with nothing buffered returns an empty string successfully, so an empty result is not an error. Retrieve text promptly after a channel completes, before other SSH operations can discard the completed channel record.

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C++

#include <CkSsh.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Demonstrates the Ssh.GetReceivedText method, which decodes and returns all text currently in
    //  a channel's normal receive buffer.  The 1st argument is the channel number and the 2nd is the
    //  charset.  The receive buffer is cleared after the text is returned.

    CkSsh ssh;

    int sshPort = 22;
    success = ssh.Connect("ssh.example.com",sshPort);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    const char *password = "mySshPassword";

    success = ssh.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    int channelNum = ssh.OpenSessionChannel();
    if (channelNum < 0) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    success = ssh.SendReqExec(channelNum,"cat /etc/hostname");
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    //  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
    //  it, this call waits forever if the server never sends channel close.
    ssh.put_ReadTimeoutMs(15000);

    success = ssh.ChannelReceiveToClose(channelNum);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    //  Retrieve the accumulated output.  A valid channel with no buffered data returns an empty
    //  string successfully.
    const char *output = ssh.getReceivedText(channelNum,"utf-8");
    if (ssh.get_LastMethodSuccess() == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    std::cout << output << "\r\n";

    ssh.Disconnect();
    }