connection.swift

import UIKit

let SingletonErrorDomain = "SingletonErrorDomain"

class Singleton {
    static let sharedInstance = Singleton()

    var activeTask :NSURLSessionDataTask?

    final func getURL(URLString :String, HTTPMethod :String, completion :(NSDictionary?, NSError?) -> Void) {
        let request : NSMutableURLRequest = NSMutableURLRequest()
        request.URL = NSURL(string: URLString)
        request.HTTPMethod = HTTPMethod
        self.activeTask?.cancel()
        self.activeTask = NSURLSession.sharedSession().dataTaskWithRequest(request) { data, response, error in
            self.activeTask = nil
            if error != nil {
                completion(nil, error)
                return
            }
            guard let data = data else {
                completion(nil, NSError(domain: SingletonErrorDomain, code: 0, userInfo: [NSLocalizedDescriptionKey: NSLocalizedString("No data fetched", comment: "")]))
                return
            }
            guard let parsedDictionary = try? NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions(rawValue: 0)) as? NSDictionary else {
                completion(nil, NSError(domain: SingletonErrorDomain, code: 0, userInfo: [NSLocalizedDescriptionKey: NSLocalizedString("JSON error", comment: "")]))
                return
            }
            completion(parsedDictionary, nil)
        }
        self.activeTask?.resume()
    }
}

//var semaphore = dispatch_semaphore_create(0)
//
//Singleton.sharedInstance.getURL("https://raw.githubusercontent.com/g0v/hack.g0v.tw/master/g0v.json", HTTPMethod: "GET") {dictionary, error in
//  if let dictionary = dictionary {
//      print("\(dictionary)")
//  }
//  dispatch_semaphore_signal(semaphore)
//}
//dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER)