(Objective-C) FTP through SSH Tunnel

Demonstrates how to FTP through an SSH tunnel.

The Chilkat SSH tunnel object is used to create a portable SSH tunnel w/ dynamic port forwarding on a background thread that the foreground thread can use for establishing connections through an SSH tunnel.

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#import <CkoGlobal.h>
#import <CkoSshTunnel.h>
#import <NSString.h>
#import <CkoFtp2.h>

// 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.
CkoGlobal *chilkatGlob = [[CkoGlobal alloc] init];
BOOL success = [chilkatGlob UnlockBundle: @"Anything for 30-day trial."];
if (success != YES) {
    NSLog(@"%@",chilkatGlob.LastErrorText);
    return;
}

// This example requires Chilkat version 9.5.0.50 or greater.
CkoSshTunnel *tunnel = [[CkoSshTunnel alloc] init];

NSString *sshHostname = @"sftp.example.com";
int sshPort = 22;

// Connect to an SSH server and establish the SSH tunnel:
success = [tunnel Connect: sshHostname port: [NSNumber numberWithInt: sshPort]];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

// Authenticate with the SSH server via a login/password
// or with a public key.  
// This example demonstrates SSH password authentication.
success = [tunnel AuthenticatePw: @"mySshLogin" password: @"mySshPassword"];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

// Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
// with dynamic port forwarding:
tunnel.DynamicPortForwarding = YES;

// 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.InboundSocksUsername = @"chilkat123";
tunnel.InboundSocksPassword = @"password123";

// Start the listen/accept thread to begin accepting SOCKS proxy client connections.
// Listen on port 1080.
success = [tunnel BeginAccepting: [NSNumber numberWithInt: 1080]];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

// 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 Socket, 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.

// Let's do an FTP upload through the SSH tunnel.  Both the control and data connections 
// go through the tunnel.
CkoFtp2 *ftp = [[CkoFtp2 alloc] init];

ftp.Hostname = @"ftp.example.com";
ftp.Username = @"login";
ftp.Password = @"password";

// Indicate that the FTP2 object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
ftp.SocksHostname = @"localhost";
ftp.SocksPort = [NSNumber numberWithInt:1080];
ftp.SocksVersion = [NSNumber numberWithInt:5];
ftp.SocksUsername = @"chilkat123";
ftp.SocksPassword = @"password123";

// Connect to the FTP server
success = [ftp ConnectOnly];
if (success != YES) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

// Authenticate with the FTP server.
success = [ftp LoginAfterConnectOnly];
if (success != YES) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

// Change to the remote directory where the file will be uploaded.
success = [ftp ChangeRemoteDir: @"junk"];
if (success != YES) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

// Upload a file.
NSString *localPath = @"/temp/hamlet.xml";
NSString *remoteFilename = @"hamlet.xml";

success = [ftp PutFile: localPath remoteFilename: remoteFilename];
if (success != YES) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

// This closes the SSH channel within the SSH tunnel,
// and thus closes the connection with the FTP server.
success = [ftp Disconnect];

NSLog(@"%@",@"File Uploaded!");

// Stop the background listen/accept thread:
BOOL waitForThreadExit = YES;
success = [tunnel StopAccepting: waitForThreadExit];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

// Close the SSH tunnel (would also kick any remaining connected clients).
success = [tunnel CloseTunnel: waitForThreadExit];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}