JavaScript

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.

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

JavaScript

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 CkSsh();

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 CkStringBuilder();
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();