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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.

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const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    const tunnel = try chilkat.SshTunnel.init();
    defer tunnel.deinit();

    const ssh_hostname = "sftp.example.com";
    const ssh_port = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    tunnel.connect(ssh_hostname, ssh_port) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // Authenticate with the SSH server via a login/password
    // or with a public key.
    // This example demonstrates SSH password authentication.
    tunnel.authenticatePw("mySshLogin", "mySshPassword") catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
    // with dynamic port forwarding:
    tunnel.setDynamicPortForwarding(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.setInboundSocksUsername("chilkat123");
    tunnel.setInboundSocksPassword("password123");

    // Start the listen/accept thread to begin accepting SOCKS proxy client connections.
    // Listen on port 1080.
    tunnel.beginAccepting(1080) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        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.
    const ftp = try chilkat.Ftp2.init();
    defer ftp.deinit();

    ftp.setHostname("ftp.example.com");
    ftp.setUsername("login");
    ftp.setPassword("password");

    // Indicate that the FTP2 object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
    ftp.setSocksHostname("localhost");
    ftp.setSocksPort(1080);
    ftp.setSocksVersion(5);
    ftp.setSocksUsername("chilkat123");
    ftp.setSocksPassword("password123");

    // Connect to the FTP server
    ftp.connectOnly() catch {
        std.debug.print("{s}\n", .{try ftp.getLastErrorText(alloc)});
        return;
    };

    // Authenticate with the FTP server.
    ftp.loginAfterConnectOnly() catch {
        std.debug.print("{s}\n", .{try ftp.getLastErrorText(alloc)});
        return;
    };

    // Change to the remote directory where the file will be uploaded.
    ftp.changeRemoteDir("junk") catch {
        std.debug.print("{s}\n", .{try ftp.getLastErrorText(alloc)});
        return;
    };

    // Upload a file.
    const local_path = "/temp/hamlet.xml";
    const remote_filename = "hamlet.xml";

    ftp.putFile(local_path, remote_filename) catch {
        std.debug.print("{s}\n", .{try ftp.getLastErrorText(alloc)});
        return;
    };

    // This closes the SSH channel within the SSH tunnel,
    // and thus closes the connection with the FTP server.
    try ftp.disconnect();

    std.debug.print("File Uploaded!\n", .{});

    // Stop the background listen/accept thread:
    const wait_for_thread_exit = true;
    tunnel.stopAccepting(wait_for_thread_exit) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // Close the SSH tunnel (would also kick any remaining connected clients).
    tunnel.closeTunnel(wait_for_thread_exit) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };
}