(Objective-C) Async Task Chain (another example)

Demonstrates using a task chain to run a sequence of FTP tasks asynchronously.

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#import <CkoGlobal.h>
#import <CkoFtp2.h>
#import <CkoTaskChain.h>
#import <CkoTask.h>
#import <NSString.h>

// All Chilkat classes can be unlocked at once at the beginning of a program
// by calling UnlockBundle.  It requires a Bundle unlock code.
CkoGlobal *chilkatGlob = [[CkoGlobal alloc] init];
BOOL success = [chilkatGlob UnlockBundle: @"Anything for 30-day trial."];
if (success != YES) {
    NSLog(@"%@",chilkatGlob.LastErrorText);
    return;
}

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

ftp.Hostname = @"ftp.example.com";
ftp.Username = @"login";
ftp.Password = @"password";

// Connect and login to the FTP server.
success = [ftp Connect];
if (success != YES) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

CkoTaskChain *taskChain = [[CkoTaskChain alloc] init];

// Create a task to change to the remote directory where the file will be uploaded.
CkoTask *task = [ftp ChangeRemoteDirAsync: @"junk"];
if (ftp.LastMethodSuccess == NO) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

// Add this task to the task chain.
success = [taskChain Append: task];

// Create a task to upload a file.
NSString *localFilename = @"c:/temp/hamlet.xml";
NSString *remoteFilename = @"hamlet.xml";

task = [ftp PutFileAsync: localFilename remoteFilename: remoteFilename];
if (ftp.LastMethodSuccess == NO) {
    NSLog(@"%@",ftp.LastErrorText);
    return;
}

// Add this task to the task chain.
success = [taskChain Append: task];

// Start the task chain running in a background thread.
// Each task is run one after the other (on the same background thread) until all tasks have completed.
// The task chain will stop at the first task that fails.
taskChain.StopOnFailedTask = YES;
success = [taskChain Run];
if (!success) {
    NSLog(@"%@",taskChain.LastErrorText);
    return;
}

// The application is now free to do anything else
// while the FTP commands are being run...

// For this example, we'll simply sleep and periodically
// check to see if the taskchain if finished. 
while (taskChain.Finished != YES) {

    // Sleep 100 ms.
    [taskChain SleepMs: [NSNumber numberWithInt: 100]];

}

// A finished task chain could be one that was canceled, aborted, or truly finished.  

// If the task chain "completed", then it ran to completion.  A "completed" task will
// have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
// been aborted or canceled:
if ([taskChain.StatusInt intValue] != 7) {
    NSLog(@"%@",@"Task did not complete.");
    NSLog(@"%@%@",@"task chain status: ",taskChain.Status);
    return;
}

// If we got to this point, the ChangeRemoteDir and PutFile were successful.
// We can visually verify by examining the LastErrorText that was recorded for each
// of these method calls..
int numTasks = [taskChain.NumTasks intValue];
int taskIdx = 0;

while ((taskIdx < numTasks)) {

    task = [taskChain GetTask: [NSNumber numberWithInt: taskIdx]];

    // Examine the status of this task, and the ResultErrorText
    // (the ResultErrorText is the ftp.LastErrorText captured for FTP method called by the task).
    // Everything should indicate success.
    NSLog(@"%@%@",@"task status: ",task.Status);
    NSLog(@"%@%@",@"task log: ",task.ResultErrorText);

    taskIdx = taskIdx + 1;
}

success = [ftp Disconnect];