Rust Requires Chilkat v11.0.0+

IMAP Use Existing SSH Tunnel

Demonstrates how to connect to an IMAP server using an existing SSH tunnel. This creates a new channel within the SSH tunnel, which can be a TCP or TLS connection, and is connected to a remote IMAP server through port forwarding. Rust

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

let tunnel = chilkat::Socket::new();

let ssh_hostname = "sftp.example.com".to_string();
let ssh_port = 22;

// Connect to an SSH server and establish the SSH tunnel:
if tunnel.ssh_open_tunnel(&ssh_hostname, ssh_port).is_err() {
    println!("{}", tunnel.last_error_text());
    return;
}

// Authenticate with the SSH server via a login/password
// or with a public key.  
// This example demonstrates SSH password authentication.
// Note: This is not authenticating with the IMAP server, it is
// for authenticating with the SSH server, which is separate.
if tunnel.ssh_authenticate_pw("mySshLogin", "mySshPassword").is_err() {
    println!("{}", tunnel.last_error_text());
    return;
}

// OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
// Once the channel is obtained, the Socket API may
// be used exactly the same as usual, except all communications
// are sent through the channel in the SSH tunnel.
// Any number of channels may be created from the same SSH tunnel.
// Multiple channels may coexist at the same time.

let imap = chilkat::Imap::new();

// Let the IMAP object also use the SSH tunnel
if imap.use_ssh_tunnel(&tunnel).is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// Connect to an IMAP server via the already established SSH tunnel.
// Because the SSH tunnel has been previously setup,
// this does not establish a direct connection with the IMAP
// server.  It directs the SSH server to establish the connection.

// In this example, the IMAP server requires SSL/TLS.  The TLS connection
// will be enclosed within the SSH tunnel.
imap.set_ssl(true);
imap.set_port(993);
if imap.connect("imap.my-imap-server.com").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// Authenticate with the IMAP server via the SSH tunnel.
if imap.login("myLogin", "myPassword").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// Select an IMAP mailbox
if imap.select_mailbox("Inbox").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// How many messages in Inbox?
let msg_count = imap.num_messages();
if msg_count == 0 {
    println!("No messages found.");
    return;
}

let mut upper_bound = 10;
if msg_count < upper_bound {
    upper_bound = msg_count;
}

// Download up to the 1st 10 messages.
let email = chilkat::Email::new();
let b_uid = false;
for i in 1..=upper_bound {

    if imap.fetch_email(false, i as u32, b_uid, &email).is_err() {
        println!("{}", imap.last_error_text());
        return;
    }

    println!("{}", email.from());
    println!("{}", email.subject());

}

// Disconnect from the IMAP server.
// The SSH tunnel remains open.
if imap.disconnect().is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// It is possible to re-use the existing SSH tunnel for the next connection:
if imap.connect("imap.my-imap-server2.com").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// Review the LastErrorText to see that the connection was made via the SSH tunnel:
println!("{}", imap.last_error_text());

// This closes the SSH channel, which is the connection with the IMAP server.
// It does not close the SSH tunnel
if imap.disconnect().is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// Finally, close the SSH tunnel.

// Note: If other objects are using the same SSH tunnel, the tunnel is not 
// actually closed.  It is only closed when the last object using the tunnel closes it.

// At this point, both the imap and tunnel objects have references to the internal
// SSH tunnel.  We need to close each.

// This call doesn't actually close the tunnel yet, because the tunnel object still
// holds an internal reference.
if imap.ssh_close_tunnel().is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// This actually closes the SSH tunnel because it's the last object using it.
if tunnel.ssh_close_tunnel().is_err() {
    println!("{}", tunnel.last_error_text());
    return;
}

println!("IMAP pre-existing SSH tunnel example completed.");