PHP

Check Whether an SSH Channel is Open

Demonstrates the Chilkat Ssh.ChannelIsOpen method, which reports whether a channel number identifies a channel Chilkat currently considers open for application I/O. The only argument is the channel number. This example checks the channel before and after sending CLOSE.

Background: Because one SSH connection can carry many channels with independent lifetimes, code that manages several needs a way to ask whether a given one is still usable. This returns false for invalid or nonexistent channel numbers, after a local Disconnect, once remote closure is processed, and immediately after ChannelSendClose — which marks the channel locally closed without waiting for the remote side.

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<?php

use Chilkat2\Ssh;

// Demonstrates the Ssh.ChannelIsOpen method, which reports whether a channel number identifies
// a channel Chilkat currently considers open for application I/O.  The only argument is the
// channel number.

$ssh = new Ssh();

$sshPort = 22;
try {
    $ssh->Connect('ssh.example.com', $sshPort);

    // 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.
    $password = 'mySshPassword';

    $ssh->AuthenticatePw('mySshLogin', $password);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Open a session channel.  A negative return value indicates failure.
$channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    echo $ssh->LastErrorText, "\n";
    exit;
}

if ($ssh->ChannelIsOpen($channelNum)) {
    echo "The channel is open.\n";
} else {
    echo "The channel is not open.\n";
}

// Send CLOSE, which immediately marks the channel locally closed.
try {
    $ssh->ChannelSendClose($channelNum);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

if ($ssh->ChannelIsOpen($channelNum)) {
    echo "Still open.\n";
} else {
    echo "The channel is now closed.\n";
}

$ssh->Disconnect();