Objective-C

IMAP SSH Tunneling (Port Forwarding)

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

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

BOOL success = NO;

//  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:
success = [imap SshOpenTunnel: sshHostname sshPort: [NSNumber numberWithInt: sshPort]];
if (success == NO) {
    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 == NO) {
    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 == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

//  Authenticate with the IMAP server via the SSH tunnel.
success = [imap Login: @"myLogin" password: @"myPassword"];
if (success == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

//  Select an IMAP mailbox
success = [imap SelectMailbox: @"Inbox"];
if (success == NO) {
    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.
CkoEmail *email = [[CkoEmail alloc] init];
int i;
BOOL bUid = NO;
for (i = 1; i <= upperBound; i++) {

    success = [imap FetchEmail: NO msgId: i bUid: bUid email: email];
    if (success == NO) {
        NSLog(@"%@",imap.LastErrorText);
        return;
    }

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

//  Disconnect from the IMAP server.
//  The SSH tunnel remains open.
success = [imap Disconnect];
if (success == NO) {
    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 == NO) {
    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 == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

//  Finally, close the SSH tunnel.
success = [imap SshCloseTunnel];
if (success == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

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