Objective-C

FTP through SSH Tunnel

See more FTP Examples

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.

Objective-C

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

BOOL success = NO;

//  This example assumes the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

success = NO;

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;
}