AFNetworking updating URL in request - objective-c

Question

Is there any easy way to update a request's URL after it was initiated in AFNetworking?
Let's say my app is downloading a 2GB in chunks, we'll have 200 chunks 10MB each. For each I'm creating a AFHTTPRequestOperation and add it to the queue.
Problem is, that the server from which I'm downloading has a timeout on all URLs, which means I'll get 403 after that time and I have to generate a new one. I need to do it before the time runs out.
for (DownloadFile *downloadFile in [download filesInTheDownload])
{
for (DownloadChunk *downloadChunk in [downloadFile chunksInTheFile])
{
NSURL *fileURL = [[NSURL alloc] initWithString:[downloadFile filePath]];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:fileURL];
NSLog(#"Normal range: %lli-%lli", [downloadChunk startingByte], [downloadChunk endingByte]);
NSString *range = [NSString stringWithFormat:#"bytes=%lli-%lli", newStartingByte, [downloadChunk endingByte]];
[request setValue:range forHTTPHeaderField:#"Range"];
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
operation.outputStream = [NSOutputStream outputStreamToFileAtPath:chunkPath append:YES];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"%#", [NSString stringWithFormat:#"Chunk complete: %#.%i", [downloadFile fileName], [downloadChunk chunkId]]);
if (download.downloadedBytes == download.size)
[[NSNotificationCenter defaultCenter] postNotificationName:#"downloadFinished" object:download];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Error: %#", error);
}];
[operation setDownloadProgressBlock:^(NSInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) {
download.downloadedBytes += bytesRead;
}];
[queue addOperation:operation];
}
}

Answer 1

No, it's not possible to modify a scheduled operation. Generally it's a good thing, meaning that you can schedule the operation and be absolutely sure that it's going to be executed based on original conditions.
I see two options in your case. First, you can schedule operations one by one, and verify if the link is valid, updating it if required.
Second, you can react to 403 Forbidden by updating the link and re-scheduling same operation.