Objective-C

Throttle FTP Transfer Bandwidth

Demonstrates the bandwidth properties BandwidthThrottleUp and BandwidthThrottleDown, and the read-only UploadTransferRate and DownloadTransferRate.

Note: The local paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Throttling caps the approximate transfer rate in bytes per second (0 means unlimited), which is how a background sync avoids starving interactive traffic on a shared or metered link. The rate properties report the current measured throughput, updated during transfers, so you can display progress or confirm the throttle is taking effect. Treat the limits as approximate targets rather than hard ceilings.

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Objective-C

#import <CkoFtp2.h>

BOOL success = NO;

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

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

//  Limit the approximate transfer rate in bytes per second.  0 (the default) means no limit.
//  Throttling is useful to avoid saturating a shared link.
ftp.BandwidthThrottleDown = [NSNumber numberWithInt:1048576];
ftp.BandwidthThrottleUp = [NSNumber numberWithInt:524288];

//  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";

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

success = [ftp GetFile: @"public_html/bigfile.zip" localPath: @"qa_output/bigfile.zip"];
if (success == NO) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

//  The current average rates are updated during transfers.
NSLog(@"%@%d%@",@"Download rate: ",[ftp.DownloadTransferRate intValue],@" bytes/sec");
NSLog(@"%@%d%@",@"Upload rate: ",[ftp.UploadTransferRate intValue],@" bytes/sec");

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