let stringURL = "..."        
let url = NSURL(string: stringURL)!
let request = NSURLRequest(URL: url)
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: config)

let networkPromise = Promise<NSData, NSError>()

let task : NSURLSessionDataTask = session.dataTaskWithRequest(request) { (data, response, error) in

    if let e = error {
        networkPromise.tryFailure(e)
    } else {
        if let d = data {
            networkPromise.trySuccess(d)
        } else {
            networkPromise.tryFailure(NSError(domain: "Data error", code: -1, userInfo: nil))
        }
    }

}

networkPromise.future
    .flatMap() { value in
        return self.deserializeData(value)
    }
    .rx_observable()
    .subscribeNext() { json in
        self.toTextField.text = self.processData(json)
    }

task.resume()