(PHP Extension) FTP through SSH Tunnel with Dynamic Port Forwarding

Demonstrates how to start a background thread that runs a portable SSH tunnel w/ dynamic port forwarding that the foreground thread can be used for establishing FTP sessions through an SSH tunnel.

Note: Some developers may be accustomed to starting an stunnel.exe proxy from https://www.stunnel.org. The stunnel.exe is not necessary here. Chilkat's background thread fulfills the task of what the external stunnel.exe does. Therefore, your application is self-contained, meaning that it can run anywhere because the SSH tunnel proxy is built-in.

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux, Solaris

<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

// Starting in v9.5.0.49, all Chilkat classes can be unlocked at once at the beginning of a program
// by calling UnlockBundle.  It requires a Bundle unlock code.
$chilkatGlob = new CkGlobal();
$success = $chilkatGlob->UnlockBundle('Anything for 30-day trial.');
if ($success != true) {
    print $chilkatGlob->lastErrorText() . "\n";
    exit;
}

// This example requires Chilkat version 9.5.0.50 or greater.
$tunnel = new CkSshTunnel();

$sshHostname = 'sftp.example.com';
$sshPort = 22;

// Connect to an SSH server and establish the SSH tunnel:
$success = $tunnel->Connect($sshHostname,$sshPort);
if ($success != true) {
    print $tunnel->lastErrorText() . "\n";
    exit;
}

// Authenticate with the SSH server via a login/password
// or with a public key.  
// This example demonstrates SSH password authentication.
$success = $tunnel->AuthenticatePw('mySshLogin','mySshPassword');
if ($success != true) {
    print $tunnel->lastErrorText() . "\n";
    exit;
}

// Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
// with dynamic port forwarding:
$tunnel->put_DynamicPortForwarding(true);

// We may optionally require that connecting clients authenticate with our SOCKS proxy server.
// To do this, set an inbound username/password.  Any connecting clients would be required to 
// use SOCKS5 with the correct username/password.
// If no inbound username/password is set, then our SOCKS proxy server will accept both
// SOCKS4 and SOCKS5 unauthenticated connections.

$tunnel->put_InboundSocksUsername('chilkat123');
$tunnel->put_InboundSocksPassword('password123');

// Start the listen/accept thread to begin accepting SOCKS proxy client connections.
// Listen on port 1080.
$success = $tunnel->BeginAccepting(1080);
if ($success != true) {
    print $tunnel->lastErrorText() . "\n";
    exit;
}

// Now that a background thread is running a SOCKS proxy server that forwards connections
// through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
// such as HTTP, POP3, SMTP, IMAP, FTP, etc.  The protocol may use SSL/TLS because the SSL/TLS
// will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
// connections may be routed through the SSH tunnel.

$ftp = new CkFtp2();

// Indicate that the HTTP object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
$ftp->put_SocksHostname('localhost');
// The SocksPort must equal the port passed to BeginAccepting above.
$ftp->put_SocksPort(1080);
$ftp->put_SocksVersion(5);
// The SOCKS5 login/password set here must equal the InboundSocksUsername/Password set above.
$ftp->put_SocksUsername('chilkat123');
$ftp->put_SocksPassword('password123');

// This is the actual FTP server domain or IP address, and the login/password for the user account on the destination FTP server.
$ftp->put_Hostname('ftp.someFtpServer.com');
$ftp->put_Username('myLogin');
$ftp->put_Password('myPassword');
$ftp->put_AuthTls(true);

// Connect and login (via the SSH tunnel) to the FTP server.
$success = $ftp->Connect();
if ($success != true) {
    print $ftp->lastErrorText() . "\n";
    exit;
}

// Change to the remote directory where the file is located.
// This step is only necessary if the file is not in the root directory
// for the FTP account.
$success = $ftp->ChangeRemoteDir('junk');
if ($success != true) {
    print $ftp->lastErrorText() . "\n";
    exit;
}

$localFilename = 'c:/temp/hamlet.xml';
$remoteFilename = 'hamlet.xml';

// Download a file.  (the data connection is also automatically established through the 
// SSH tunnel using dynamic port forwarding..)
$success = $ftp->GetFile($remoteFilename,$localFilename);
if ($success != true) {
    print $ftp->lastErrorText() . "\n";
    exit;
}

// The disconnect is disconnecting with the FTP server and closes the SSH tunnel.
// The background tunnel thread is still running, and may be used for subsequent FTP connections,
// or even connections for any other purpose, such as HTTP, IMAP, SMTP, POP3, etc.
$success = $ftp->Disconnect();

// When the app is finished with the tunnel, it can cleanup..

// Stop the background listen/accept thread:
$waitForThreadExit = true;
$success = $tunnel->StopAccepting($waitForThreadExit);
if ($success != true) {
    print $tunnel->lastErrorText() . "\n";
    exit;
}

// Close the SSH tunnel (would also kick any remaining connected clients).
$success = $tunnel->CloseTunnel($waitForThreadExit);
if ($success != true) {
    print $tunnel->lastErrorText() . "\n";
    exit;
}


?>