Multiple photo background image upload and memory - ios

Question

I'm trying to upload multiple photos in background mode using AFNetworking and I managed to make it work.
The main problem I'm facing now is memory, which, while uploading more than 10 photos, runs out terminating my app.
What I'm doing is just firing all the uploads simultaneously as I've read in some answers on StackOverflow.
Now that this problem arises I'm wondering if I'm doing something wrong with memory management or if a better strategy would be to serialize the uploads, start the first one and when it terminates start the upload of the next in the handleEventsForBackgroundURLSession method.
Before changing completely the upload design I would like to hear from someone if it's a good alternative, as the majority of answers I've seen regarding this matter state that one should fire all the requests together.
Thank you

Answer 1

Create NSOperationQueue and add all your upload image operation to that queue. This queue will manage your system memory. Please refer below sample code.
NSOperationQueue *myQueue = [[NSOperationQueue alloc]init];
NSURLRequest *request = [[AFHTTPRequestSerializer serializer]
multipartFormRequestWithMethod:#"POST"
URLString:apiPostPhoto(singleton.userId, #"icon")
parameters:nil
constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
NSString *filepath = [[CustomFunctions getFilesPath] stringByAppendingPathComponent:#"icon.png"];
[formData appendPartWithFileURL:[NSURL fileURLWithPath:filepath] name:#"uploadicon" error:nil];
} error:nil
];
AFHTTPRequestOperation *operationUploadOne = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"uploadlogo:%#",operation.responseString);
[[NSUserDefaults standardUserDefaults]setObject:operation.responseString forKey:KEY_LOGO_TIMESTAMP];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"uploadlogo:%#",[error description]);
}];
[operation addObserver:self forKeyPath:#"isFinished" options:NSKeyValueObservingOptionNew context:nil];
[myQueue addOperation:operationUploadOne];
AFHTTPRequestOperation *operationUploadTwo = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[op setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
}];
[myQueue addOperation: operationUploadTwo];
you can add more number of operation using this method.
[myQueue addOperation: operationUploadTwo];