Has anyone been successful in chaining NSURLSession background uploads?
I am trying to upload a huge video file in 5 MB parts using background upload of NSURLSession. The uploads has to be in order. The whole thing works fine in foreground. I am using AFNetwoking for this, and its a multi part upload. But when the app is in background, the first item uploads fine and starts the second one in background (in setDidFinishEventsForBackgroundURLSessionBlock of AFURLSessionManager). But it stops abruptly (my best guess is in 30 seconds, as an app woken up in background has a max lifetime of 30 sec) and then nothing happens. I expected the second session will finish in background and call up the third etc - a chain behaviour, but this just does not seem to work.
I have tried adding all file parts to a single NSURLSession in one go with a HTTPMaximumConnectionsPerHost = 1 - this works fine and uploads the full file in parts. But the file parts are picked in random order, i.e. part 1 gets uploaded, then part 5, part 3, part 10 etc …. I tried adding this in an NSOperationQueue with dependency between operations and this seems to mess up the entire thing - the upload does not work at all.
I know that the video file can be uploaded as a single file in background, but the server expects this in 5 MB parts. Hence I guess my only option is to chain uploads, or add all the parts to a NSURLSession, but make sure they are always uploaded in the order they are added.
Any help would be appreciated.
My code:
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSURLSessionConfiguration *config = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:[NSString stringWithFormat:@"%d", rand()]];
AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:config];
config.HTTPMaximumConnectionsPerHost = 1;
[manager setDidFinishEventsForBackgroundURLSessionBlock:^(NSURLSession *session) {
dispatch_async(dispatch_get_main_queue(), ^{
// Call the completion handler to tell the system that there are no other background transfers.
// completionHandler();
[self upload];
});
}];
}
- (IBAction)start:(id)sender {
[self upload];
}
-(void) upload {
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"Sample" ofType:@"mp4"];
AFHTTPRequestSerializer *serializer = [AFHTTPRequestSerializer serializer];
NSDictionary *parameters = [NSDictionary dictionaryWithObjectsAndKeys:@"234", @"u", @"Sample.mp4", @"f",nil];
NSMutableURLRequest *request = [serializer multipartFormRequestWithMethod:@"POST" URLString:urlString parameters:parameters constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
[formData appendPartWithFileURL:[NSURL fileURLWithPath:filePath] name:@"data" fileName:@"Sample.mp4" mimeType:@"video/mp4" error:nil];
} error:nil];
__block NSString *tempMultipartFile = [NSTemporaryDirectory() stringByAppendingPathComponent:@"Test"];
tempMultipartFile = [tempMultipartFile stringByAppendingString:[NSString stringWithFormat:@"%d", rand()]];
NSURL *filePathtemp = [NSURL fileURLWithPath:tempMultipartFile];
__block NSProgress *progress = nil;
[serializer requestWithMultipartFormRequest:request writingStreamContentsToFile:filePathtemp completionHandler:^(NSError *error) {
NSURLSessionUploadTask *uploadTask = [manager uploadTaskWithRequest:request fromFile:filePathtemp progress:&progress completionHandler:^(NSURLResponse *response, id responseObject, NSError *error) {
NSLog(@"Request--> %@.\n Response --> %@ \n%@", request.URL.absoluteString ,responseObject, error? [NSString stringWithFormat:@" with error: %@", [error localizedDescription]] : @""); //Lets us know the result including failures
[[NSFileManager defaultManager] removeItemAtPath:tempMultipartFile error:nil];
}];
[uploadTask resume];
[manager setTaskDidSendBodyDataBlock:^(NSURLSession *session, NSURLSessionTask *task, int64_t bytesSent, int64_t totalBytesSent, int64_t totalBytesExpectedToSend) {
NSLog(@"uploading");
}];
}];
}
