Using AWSS3TransferUtility to upload data on iOS - ios

Question

I've managed to successfully upload data using the AWS 2.0 SDK, however I'm having some trouble understanding the "re-wiring" of completion handlers that is meant to take place on resuming of the app.
What I believe I should be doing, is at comment 6, saving the upload task. Then if it reaches the completionHandler block, deleting it. However, if the app is terminated before this, I can look at my saved upload tasks in the block at comment 4. Any saved tasks would be "re-wired" to the completion handler.
For reference, imagine this code happening in an "Upload" class, and in a block, which is the "uploadSuccess()" code you see in the completionHandler.
For reference here is the blog that introduced the AWSS3TransferUtility, and here is its documentation.
Hopefully someone can guide me on this.
// 1. Get/Setup credentials
AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:AWSRegionUSEast1 identityPoolId:#"IdentityPoolId"];
AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionUSEast1 credentialsProvider:credentialsProvider];
AWSServiceManager.defaultServiceManager.defaultServiceConfiguration = configuration;
// 2. Create AWSS3 Transfer blocks
AWSS3TransferUtilityUploadExpression *expression = [AWSS3TransferUtilityUploadExpression new];
expression.uploadProgress = ^(AWSS3TransferUtilityTask *task, int64_t bytesSent, int64_t totalBytesSent, int64_t totalBytesExpectedToSend) {
dispatch_async(dispatch_get_main_queue(), ^{
// Do something e.g. Update a progress bar.
});
};
AWSS3TransferUtilityUploadCompletionHandlerBlock completionHandler = ^(AWSS3TransferUtilityUploadTask *task, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
// Do something e.g. Alert a user for transfer completion.
// On failed uploads, `error` contains the error object.
if (error) {
uploadSuccess(NO);
} else {
uploadSuccess(YES);
}
});
};
// 3. Create Transfer Utility
AWSS3TransferUtility *transferUtility = [AWSS3TransferUtility defaultS3TransferUtility];
// 4. Rewire Transfer Utility blocks
[transferUtility
enumerateToAssignBlocksForUploadTask:^(AWSS3TransferUtilityUploadTask *uploadTask, __autoreleasing AWSS3TransferUtilityUploadProgressBlock *uploadProgressBlockReference, __autoreleasing AWSS3TransferUtilityUploadCompletionHandlerBlock *completionHandlerReference) {
NSLog(#"Upload task identifier = %lu", (unsigned long)uploadTask.taskIdentifier);
// Use `uploadTask.taskIdentifier` to determine what blocks to assign.
//*uploadProgressBlockReference = // Reassign your progress feedback block.
*completionHandlerReference = completionHandler;// Reassign your completion handler.
}
downloadTask:^(AWSS3TransferUtilityDownloadTask *downloadTask, __autoreleasing AWSS3TransferUtilityDownloadProgressBlock *downloadProgressBlockReference, __autoreleasing AWSS3TransferUtilityDownloadCompletionHandlerBlock *completionHandlerReference) {
}];
// 5. Upload data using Transfer Utility
[[transferUtility uploadData:myNSDataObject
bucket:#"bucketName"
key:#"keyName"
contentType:#"text/plain"
expression:expression
completionHander:completionHandler] continueWithBlock:^id(AWSTask *task) {
if (task.error) {
NSLog(#"Error: %#", task.error);
}
if (task.exception) {
NSLog(#"Exception: %#", task.exception);
}
if (task.result) {
AWSS3TransferUtilityUploadTask *uploadTask = task.result;
// 6. Should i be saving uploadTasks here?
}
return nil;
}];