We have recently migrated from AFHTTPRequestOperation to NSURLSessionDownloadTask using AFURLSessionManager in AFNetworking 3. Our users have the option of downloading items that can consists of up to around 5,000 files.
These files are mainly PDF and MP4 and range in size from 10 KB to 1 GB. As part of the migration to using NSURLSession and AFURLSessionManager we were excited to be able to hand these downloads off to the system when the app entered the background allowing the downloads to continue. But what we are experiencing is these downloads will begin to fail with an error message of
lost connection to background transfer service
-or-
"no such file or directory"
when the users selects to download upwards of 500 files, this can happen with the app in the background or foreground. We then receive these error messages on any future downloads until we kill and restart the app.
Any ideas if this is a limitation of iOS and NSURLSession with a background configuration or if we should be able to get this to work?
Our AFURLSessionManager looks like this:
NSURLSessionConfiguration *configuration =
[NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:@"com.our.app.identifier.downloads"];
[configuration setHTTPMaximumConnectionsPerHost:5];
AFURLSessionManager *sessionManager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];
[sessionManager setCompletionQueue:dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0)];
And the tasks look like this:
NSURLSessionDownloadTask *downloadTask = [self.sessionManager downloadTaskWithRequest:[self requestForItem:item] progress:nil
destination:^NSURL * _Nonnull(NSURL * _Nonnull targetPath, NSURLResponse * _Nonnull response) {
NSString *filePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
return [NSURL fileURLWithPath:[filePath stringByAppendingPathComponent:@"fileid.ext"]];
} completionHandler:^(NSURLResponse * _Nonnull response, NSURL * _Nullable filePath, NSError * _Nullable error) {
// check for error and notify the ui of completion
}];
