Java

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.

Chilkat Java Downloads

Download Chilkat for Java

Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean 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 = new CkSsh();

    int sshPort = 22;
    success = ssh.Connect("ssh.example.com",sshPort);
    if (success == false) {
        System.out.println(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.
    String password = "mySshPassword";

    success = ssh.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        System.out.println(ssh.lastErrorText());
        return;
        }

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

    success = ssh.SendReqExec(channelNum,"cat /etc/hostname");
    if (success == false) {
        System.out.println(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.put_ReadTimeoutMs(15000);

    success = ssh.ChannelReceiveToClose(channelNum);
    if (success == false) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    //  Retrieve the accumulated output.  A valid channel with no buffered data returns an empty
    //  string successfully.
    String output = ssh.getReceivedText(channelNum,"utf-8");
    if (ssh.get_LastMethodSuccess() == false) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    System.out.println(output);

    ssh.Disconnect();
  }
}