Node.js

Get Received SSH Text into a StringBuilder

Demonstrates the Chilkat Ssh.GetReceivedSb method, which decodes a channel's receive buffer and appends the text to a StringBuilder. The arguments are the channel number, the charset, and the StringBuilder. The receive buffer is cleared afterward.

Background: Because this appends rather than replaces, it is the natural choice for accumulating output across repeated reads — call it in a loop and the StringBuilder grows into the complete transcript. It also avoids creating a new string on every retrieval, which matters when a command produces a large amount of text.

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function chilkatExample() {

    var success = false;

    //  Demonstrates the Ssh.GetReceivedSb method, which decodes the channel's receive buffer and
    //  appends the text to a StringBuilder.  The 1st argument is the channel number, the 2nd is the
    //  charset, and the 3rd is the StringBuilder.  The receive buffer is cleared afterward.

    var ssh = new chilkat.Ssh();

    var sshPort = 22;
    success = ssh.Connect("ssh.example.com",sshPort);
    if (success == false) {
        console.log(ssh.LastErrorText);
        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.
    var password = "mySshPassword";

    success = ssh.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    var channelNum = ssh.OpenSessionChannel();
    if (channelNum < 0) {
        console.log(ssh.LastErrorText);
        return;
    }

    success = ssh.SendReqExec(channelNum,"ls -l /tmp");
    if (success == false) {
        console.log(ssh.LastErrorText);
        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.ReadTimeoutMs = 15000;

    success = ssh.ChannelReceiveToClose(channelNum);
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    //  Append the received text to a StringBuilder.  Existing content is preserved.
    var sb = new chilkat.StringBuilder();
    success = ssh.GetReceivedSb(channelNum,"utf-8",sb);
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    console.log("Characters received: " + sb.Length);
    var output = sb.GetAsString();
    console.log(output);

    ssh.Disconnect();

}

chilkatExample();