How to get download progress in AFNetworking 2.0?
I am using AFURLSessionManager to create a new download task:
AFURLSessionManager* manager = ...
NSProgress* p = nil;
NSURLSessionDownloadTask* downloadTask =
[manager downloadTaskWithRequest:request
progress:&p
destination:^NSURL*(NSURL* targetPath, NSURLResponse* response) {...}
completionHandler:^(NSURLResponse* response, NSURL* filePath, NSError* error) {...}
];
[downloadTask resume];
The file gets downloaded fine, however, how do I get progress notifications?
p is always set to nil. I've filed an issue for that.
I've also tried to call setDownloadTaskDidWriteDataBlock on the manager, and I do get progress notifications there but I receive them all grouped together after the file has been downloaded.
Seems like this area is still a bit buggy in AFNetworking 2.0
Any ideas?
You should observe the fractionCompleted property of your NSProgress object using KVO:
NSURL *url = [NSURL URLWithString:@"http://www.hfrmovies.com/TheHobbitDesolationOfSmaug48fps.mp4"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
AFHTTPSessionManager *session = [AFHTTPSessionManager manager];
NSProgress *progress;
NSURLSessionDownloadTask *downloadTask = [session downloadTaskWithRequest:request progress:&progress destination:^NSURL *(NSURL *targetPath, NSURLResponse *response) {
// …
} completionHandler:^(NSURLResponse *response, NSURL *filePath, NSError *error) {
[progress removeObserver:self forKeyPath:@"fractionCompleted" context:NULL];
// …
}];
[downloadTask resume];
[progress addObserver:self
forKeyPath:@"fractionCompleted"
options:NSKeyValueObservingOptionNew
context:NULL];
Then add the observer method:
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
if ([keyPath isEqualToString:@"fractionCompleted"]) {
NSProgress *progress = (NSProgress *)object;
NSLog(@"Progress… %f", progress.fractionCompleted);
} else {
[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
}
}
Of course, you should check keyPath and/or object parameters to decide if that's the object/property you want to observe.
You can also use the setDownloadTaskDidWriteDataBlock: method from AFURLSessionManager (from which AFHTTPSessionManager inherits) to set a block for receiving download progress updates.
[session setDownloadTaskDidWriteDataBlock:^(NSURLSession *session, NSURLSessionDownloadTask *downloadTask, int64_t bytesWritten, int64_t totalBytesWritten, int64_t totalBytesExpectedToWrite) {
NSLog(@"Progress… %lld", totalBytesWritten);
}];
This AFNetworking method maps the URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite: method from NSURLSessionDownloadDelegate protocol to a more convenient block mechanism.
BTW, Apple's KVO implementation is severely broken. I recommend using a better implementation like the one proposed by Mike Ash with MAKVONotificationCenter. If you are interested in reading why Apple's KVO is broken, read Key-Value Observing Done Right by Mike Ash.
I faced a similar problem, and found a solution.
Check the link below: http://cocoadocs.org/docsets/AFNetworking/2.0.1/Categories/UIProgressView+AFNetworking.html
#import <AFNetworking/UIKit+AFNetworking.h>
and use the additional method available to your UIProgressView
setProgressWithDownloadProgressOfTask:animated:
How I did it:
NSURLSessionDownloadTask *downloadTask = [manager downloadTaskWithRequest:request progress:nil destination:^NSURL *(NSURL *targetPath, NSURLResponse *response){
NSURL *documentsDirectoryPath = [NSURL fileURLWithPath:[NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) firstObject]];
return [documentsDirectoryPath URLByAppendingPathComponent:[targetPath lastPathComponent]];
} completionHandler:^(NSURLResponse *response, NSURL *filePath, NSError *error){
NSLog(@"File downloaded to: %@", filePath);
}];
[self.progressView setProgressWithDownloadProgressOfTask:downloadTask animated:YES];
[downloadTask resume];
Simple solutions for Swift:
let sessionConfiguration = NSURLSessionConfiguration.defaultSessionConfiguration()
let sessionManager = AFURLSessionManager(sessionConfiguration: sessionConfiguration)
let request = NSURLRequest(URL: url)
let sessionDownloadTask = sessionManager.downloadTaskWithRequest(request, progress: nil, destination: { (url, response) -> NSURL in
return destinationPath.URLByAppendingPathComponent(fileName) //this is destinationPath for downloaded file
}, completionHandler: { response, url, error in
//do sth when it finishes
})
Now you have 2 options:
Using UIProgressView and setProgressWithDownloadProgressOfTask:
progressView.setProgressWithDownloadProgressOfTask(sessionDownloadTask, animated: true)
Using AFURLSessionManager and setDownloadTaskDidWriteDataBlock:
sessionManager.setDownloadTaskDidWriteDataBlock { session, sessionDownloadTask, bytesWritten, totalBytesWritten, totalBytesExpectedToWrite in
let progress = Float(totalBytesWritten)/Float(totalBytesExpectedToWrite)
//do sth with current progress
}
At the end do not forget about:
sessionDownloadTask.resume()