Completion block prevents AFJSONRequestOperation execution - ios

Question

I'm retrieving JSON data using AFNetworking lib, and wanted to add a completion block as follows:
-(void)getData{
NSString *link=#"http://localhost:8080/address/address/address/";
NSURL *url= [ NSURL URLWithString:link];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
arrayofA=[JSON valueForKeyPath:#"a"];
arrayofB=[JSON valueForKeyPath:#"b"];
[[self techTableView] reloadData];
} failure:nil];
[operation setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) {
//-- This block gets invoked periodically as the download progress
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(totalBytesRead * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^(void){
dispatch_async(dispatch_get_main_queue(), ^{
// HUD treatment
});
});
}];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"Completed:");
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Error: %#", error);
}];
[operation start];
}
When I added the completion bloc I no longer have a result, nothing is shown in the screen, and noticed that AFJSONRequestOperation bloc is not executed, I printed a log there and it's not shown.
What could be the problem?
Thank you very much.

Answer 1

Throw this code away:
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"Completed:");
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Error: %#", error);
}];
Instead, put your logging into the blocks on the JSONRequestOperationWithRequest:success:failure: (where you currently have a success block but no failure block, and the success block is being removed by the code that you should remove).
In setDownloadProgressBlock, just push to the main thread and update your UI. Don't bother trying to create a delay, that will only lead to apparently random behaviour. Also, don't try to use the result of the download, that should only be done in the success block.