Start an upload of an image when the app is in foreground and continue the upload when the app is sent to the background or is closed?

[stefanosn82]

I use this code to upload an image in objective c.

-(void)uploadImageInBackground:(UIImage*)image toPreSignedURL:(NSURL*)preSignedURL withCompletion:(void (^)(id _Nullable response))completion{
    
    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
    AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];
   
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:preSignedURL];
    request.HTTPMethod = @"PUT";
    [request setValue:@"image/jpeg" forHTTPHeaderField:@"Content-Type"];
    
    NSString* filePath = [self getFilePathForFileName:@"image.jpeg" image:image];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if (![fileManager fileExistsAtPath:filePath]){
        return;
    }

    NSURLSessionUploadTask *uploadTask = [manager uploadTaskWithRequest:request fromData:[NSData dataWithContentsOfFile:filePath] progress:^(NSProgress * _Nonnull uploadProgress) {
        NSLog(@"\nUpload Progress: %f", uploadProgress.fractionCompleted);

        } completionHandler:^(NSURLResponse * _Nonnull response, id  _Nullable responseObject, NSError * _Nullable error) {
            NSFileManager *fileManager = [NSFileManager new];
            [fileManager removeItemAtPath:filePath error:NULL];
            if (error) {
                completion(nil);
            }
            else{
                NSLog(@"\nhello: Upload Progress COMPLETED: %@", response);
                completion(response);
            }
    }];
    
    [uploadTask resume];
    
}

How to continue the upload when the app is sent to the background by the user or when the user closes the app?

Any help appreciated.