Objective-C

Send an FTP NOOP (Keep-Alive)

Demonstrates the Chilkat Ftp2.Noop method, which sends the FTP NOOP command. It takes no arguments and succeeds only when the server returns a positive reply.

Background: NOOP asks the server to do nothing and simply reply, which makes it the standard keep-alive: sending one periodically resets the server's idle timer so a long-running job does not lose its control connection between transfers. Because it exercises a real request/reply round trip, a successful NOOP is also firmer evidence the connection is alive than CheckConnection.

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Objective-C

#import <CkoFtp2.h>

BOOL success = NO;

//  Demonstrates the Ftp2.Noop method, which sends the FTP NOOP command.  It takes no arguments.
//  The server must return a positive reply for the method to succeed.

CkoFtp2 *ftp = [[CkoFtp2 alloc] init];

ftp.Hostname = @"ftp.example.com";
ftp.Username = @"myFtpLogin";

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
ftp.Password = @"myPassword";

//  Connect and log in (Connect performs both).
success = [ftp Connect];
if (success == NO) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

//  NOOP does nothing on the server, but a successful reply confirms the control connection is
//  still responsive -- useful as a keep-alive during an otherwise idle session.
success = [ftp Noop];
if (success == NO) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

NSLog(@"%@",@"NOOP acknowledged by the server.");

success = [ftp Disconnect];
if (success == NO) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}