extension NSURLSession {

    enum UTF8Encoding : ErrorType { case Error }
    enum JsonDecoding : ErrorType { case Error }

    func dataForRequest(request:NSURLRequest, completeWith: (dataResult: () throws -> NSData) -> Void) {

        let task = self.dataTaskWithRequest(request) { (data:NSData?, response:NSURLResponse?, error:NSError?) in

            guard let data = data else {

                completeWith(dataResult: { throw error! } )
                return
            }

            completeWith(dataResult: { return data } )
        }

        task.resume()
    }

    func textForRequest(request:NSURLRequest, completeWith: (textResult: () throws -> String) -> Void) {

        let task = self.dataTaskWithRequest(request) { (data:NSData?, response:NSURLResponse?, error:NSError?) in

            guard let data = data else {

                completeWith(textResult: { throw error! } )
                return
            }

            completeWith(textResult: {

                guard let text = String(data: data, encoding: NSUTF8StringEncoding) else {
                    throw UTF8Encoding.Error
                }

                return text
            })
        }

        task.resume()
    }

    func jsonForRequest(request:NSURLRequest, completeWith: (jsonResult: () throws -> [String:AnyObject]) -> Void) {

        let task = self.dataTaskWithRequest(request) { (data:NSData?, response:NSURLResponse?, error:NSError?) in

            guard let data = data else {

                completeWith(jsonResult: { throw error! } )
                return
            }

            completeWith(jsonResult: {

                let json = try NSJSONSerialization.JSONObjectWithData(data, options: .AllowFragments) as? [String:AnyObject]

                if json == nil {
                    throw JsonDecoding.Error
                }

                return json!
            })
        }

        task.resume()
    }

    func awaitDataForRequest(request:NSURLRequest) throws -> NSData {

        let wait: dispatch_semaphore_t = dispatch_semaphore_create(0);
        var resData:NSData?
        var resError:NSError?

        let task = self.dataTaskWithRequest(request) { (data:NSData?, response:NSURLResponse?, error:NSError?) in

            resData = data
            resError = error

            dispatch_semaphore_signal(wait)
        }

        task.resume()

        dispatch_semaphore_wait(wait, DISPATCH_TIME_FOREVER)

        guard let data = resData else {
            throw resError!
        }

        return data
    }

    func awaitTextForRequest(request:NSURLRequest) throws -> String {

        let data = try self.awaitDataForRequest(request)

        guard let text = String(data: data, encoding: NSUTF8StringEncoding) else {
            throw UTF8Encoding.Error
        }

        return text
    }

    func awaitJsonWithRequest(request:NSURLRequest) throws -> [String:AnyObject] {

        let data = try self.awaitDataForRequest(request)

        let json = try NSJSONSerialization.JSONObjectWithData(data, options: .AllowFragments) as? [String:AnyObject]

        if json == nil {
            throw JsonDecoding.Error
        }

        return json!
    }
}