How keep things DRY with afnetworking

How keep things DRY with afnetworking

I'm writing a ios app which has to send and receive data from the API at
various screens in the app. Currently each view controller is calling this
code
// AFAppDotNetAPIClient is a subclass of AFHTTPClient, which defines the
base URL and default HTTP headers for NSURLRequests it creates
[[AFAppDotNetAPIClient sharedClient]
getPath:@"stream/0/posts/stream/global" parameters:nil
success:^(AFHTTPRequestOperation *operation, id JSON) {
NSLog(@"App.net Global Stream: %@", JSON);
} failure:nil];
I want to keep things DRY and so I created a requested builder and
response handler to create request and parse responses. I also want to
move all the API calls to one class but since it uses blocks I don't know
how do this.
Can someone explain how this is done so I call one method with a enum and
some params for request and I probably just get a NSDictionary back
without having API calls and blocks in all view controllers. Thanks