First stab at a Swift network requestor

SwiftRequests.swift

//
//  SwiftRequests.swift
//

import Foundation

@objc class SwiftRequests : NSObject {
    
    enum SwiftRequestsError {
        case InvalidURL
        
        var errorObject: NSError {
            let errorString = String(self)
            let errorCode = errorString.hash
            return NSError(domain: "SwiftRequestsError", code: errorCode, userInfo: [NSLocalizedDescriptionKey:errorString])
        }
    }
    
    static func sendDataFrom(URL:String, headers:[String:String]?=nil, to completionBlock:(data:NSData?, error:NSError?) -> Void) throws {
        guard let nsURL = NSURL(string: URL) else {
            throw SwiftRequestsError.InvalidURL.errorObject
        }
        
        // create the request and add the headers
        let request = NSMutableURLRequest(URL: nsURL)
        if let headers = headers {
            for (field, value) in headers {
                request.addValue(value, forHTTPHeaderField: field)
            }
        }
        
        // fire the request
        NSURLSession.sharedSession().dataTaskWithRequest(request, completionHandler:{ data, response, error in
            completionBlock(data: data, error: error)
        }).resume()
    }
    
    static func sendStringFrom(URL:String, headers:[String:String]?=nil, to completionBlock:(string:String?, error:NSError?)->Void) throws {
        try sendDataFrom(URL, headers: headers, to:{ data, error in
            guard let data = data else {
                return completionBlock(string: nil, error: error)
            }
            
            let responseString = String(NSString.init(data: data, encoding: NSUTF8StringEncoding))
            completionBlock(string: responseString, error: nil)
        }) // if error is thrown, will bubble up
    }

    static func sendJSONFrom(URL:String, headers:[String:String]?=nil, to completionBlock:(json:AnyObject?, error:NSError?)->Void) throws {
        try sendDataFrom(URL, headers: headers, to:{ data, error in
            guard let data = data else {
                return completionBlock(json: nil, error: error)
            }
            
            var jsonObject: AnyObject?
            var jsonError: NSError?
            do {
                try jsonObject = NSJSONSerialization.JSONObjectWithData(data, options: [])
            } catch let error as NSError {
                jsonError = error
            }
            completionBlock(json: jsonObject, error: jsonError)
        }) // if error is thrown, will bubble up
    }
}