Java

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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import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Ssh;
import com.chilkatsoft.chilkat2.StringBuilder;

public class ChilkatExample {

    public static void main(String[] args) {
        // 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.

        Ssh ssh = new Ssh();

        int sshPort = 22;
        try {
            ssh.connect("ssh.example.com", sshPort);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            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.
        String password = "mySshPassword";

        try {
            ssh.authenticatePw("mySshLogin", password);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        int channelNum = ssh.openSessionChannel();
        if (channelNum < 0) {
            System.out.println(ssh.getLastErrorText());
            return;
        }

        try {
            ssh.sendReqExec(channelNum, "ls -l /tmp");

            // 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.setReadTimeoutMs(15000);

            ssh.channelReceiveToClose(channelNum);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Append the received text to a StringBuilder.  Existing content is preserved.
        StringBuilder sb = new StringBuilder();
        try {
            ssh.getReceivedSb(channelNum, "utf-8", sb);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Characters received: " + sb.getLength());
        String output = sb.getAsString();
        System.out.println(output);

        ssh.disconnect();
    }
}