Java

Check Whether SSH Channel EOF Was Received

Demonstrates the Chilkat Ssh.ChannelReceivedEof method, which reports whether an SSH EOF message has been received for a channel. The only argument is the channel number. EOF means the server will send no more ordinary channel data, but it does not close the channel.

Background: EOF and CLOSE are separate events, and the distinction matters when deciding whether a command has truly finished. A server commonly sends EOF first and CLOSE afterward; in that interval this method is true while ChannelReceivedClose is still false, and the channel remains open and counted. EOF is the signal that all output has been produced — useful when you want to stop reading without waiting for the full close handshake. It returns false for an invalid, released, or locally closed channel.

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

public class ChilkatExample {

    public static void main(String[] args) {
        // Demonstrates the Ssh.ChannelReceivedEof method, which reports whether an SSH EOF message has
        // been received for a channel.  The only argument is the channel number.  EOF means the server
        // will send no more ordinary channel data, but it does not close the channel.

        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;
        }

        if (ssh.channelReceivedEof(channelNum)) {
            System.out.println("EOF was received -- no more ordinary channel data will arrive.");
        } else {
            System.out.println("No EOF has been received.");
        }

        ssh.disconnect();
    }
}