(Objective-C) IMAP over Multiple Hop SSH

Demonstrates how to read IMAP email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => IMAPServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

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#import <CkoSsh.h>
#import <CkoImap.h>

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

CkoSsh *ssh1 = [[CkoSsh alloc] init];

// Connect directly to the 1st SSH server.
BOOL success = [ssh1 Connect: @"serverssh1.com" port: [NSNumber numberWithInt: 22]];
if (success != YES) {
    NSLog(@"%@",ssh1.LastErrorText);
    return;
}

// Authenticate using login/password:
success = [ssh1 AuthenticatePw: @"ssh1Login" password: @"ssh1Password"];
if (success != YES) {
    NSLog(@"%@",ssh1.LastErrorText);
    return;
}

// Connect through the 1st SSH connection to reach a 2nd SSH server.
// Note: Any number of SSH connections may be simultaneously tunneled through a single
// existing SSH connection.
CkoSsh *ssh2 = [[CkoSsh alloc] init];
success = [ssh2 ConnectThroughSsh: ssh1 hostname: @"serverssh2.com" port: [NSNumber numberWithInt: 22]];
if (success != YES) {
    NSLog(@"%@",ssh2.LastErrorText);
    return;
}

// Authenticate with ssh2...
success = [ssh2 AuthenticatePw: @"ssh2Login" password: @"ssh2Password"];
if (success != YES) {
    NSLog(@"%@",ssh2.LastErrorText);
    return;
}

CkoImap *imap = [[CkoImap alloc] init];

// Tell the IMAP object to connect to the IMAP server though the ssh2 tunnel (which itself is routed through ssh1).
// The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => IMAPServer
success = [imap UseSsh: ssh2];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

imap.Ssl = YES;
imap.Port = [NSNumber numberWithInt:993];

// Connect to an IMAP server (through the multi-hop SSH tunnel)
success = [imap Connect: @"imap.someimapserver.com"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// Login
success = [imap Login: @"myLogin" password: @"myPassword"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// Do whatever needs to be done...  for example,

// Create the new email folder (sub-mailbox) on the IMAP server.
// If no folder path is provided, the new folder is a sub-mailbox of Inbox.
success = [imap CreateMailbox: @"newFolder"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

NSLog(@"%@",@"Success.");

// Close the connection with the IMAP server.  (This closes the tunnel through ssh2)
// The connection with ssh2 is still alive, and may be used for more connections.
success = [imap Disconnect];

// Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
// The connection with ssh1 is still alive, and may be used for more connections.
[ssh2 Disconnect];

[ssh1 Disconnect];