(Objective-C) IMAP SSH Tunneling (Port Forwarding)

Demonstrates how to setup and use an SSH tunnel for IMAP.

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#import <CkoImap.h>
#import <NSString.h>
#import <CkoEmail.h>

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

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

// The SSH hostname may be a hostname or an 
// IP address, such as "192.168.1.108".
// The port is typically 22 (the standard port for SSH).
NSString *sshHostname = @"www.mysshserver.com";
int sshPort = 22;

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

// OK, the SSH tunnel is setup.  The IMAP component may
// be used exactly the same as usual, except all communications
// are sent through the SSH tunnel.

// Connect to an IMAP server via the 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.Ssl = YES;
imap.Port = [NSNumber numberWithInt:993];
success = [imap Connect: @"imap.my-imap-server.com"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// Authenticate with the IMAP server via the SSH tunnel.
success = [imap Login: @"myLogin" password: @"myPassword"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// Select an IMAP mailbox
success = [imap SelectMailbox: @"Inbox"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// How many messages in Inbox?
int msgCount = [imap.NumMessages intValue];
if (msgCount == 0) {
    NSLog(@"%@",@"No messages found.");
    return;
}

int upperBound = 10;
if (msgCount < upperBound) {
    upperBound = msgCount;
}

// Download up to the 1st 10 messages.
int i;
BOOL bUid = NO;
for (i = 1; i <= upperBound; i++) {

    CkoEmail *email = [imap FetchSingle: [NSNumber numberWithInt: i] bUid: bUid];
    if (imap.LastMethodSuccess == NO) {
        NSLog(@"%@",imap.LastErrorText);
        return;

    }
    else {
        NSLog(@"%@",email.From);
        NSLog(@"%@",email.Subject);
        NSLog(@"%@",@"----");

    }

}

// Disconnect from the IMAP server.
// The SSH tunnel remains open.
success = [imap Disconnect];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// It is possible to re-use the existing SSH tunnel for the next connection:
success = [imap Connect: @"imap.my-imap-server2.com"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// Review the LastErrorText to see that the connection was made via the SSH tunnel:
NSLog(@"%@",imap.LastErrorText);

success = [imap Disconnect];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// Finally, close the SSH tunnel.
success = [imap SshCloseTunnel];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

NSLog(@"%@",@"IMAP SSH tunneling example completed.");