Simple JSON REST Get

Swift REST Get JSON

    // Attempts to return requested data as Json in closure
    class func getJSON(urlString:String, completion:(json:AnyObject?, response:NSHTTPURLResponse?, error:NSError?)->()){
        
        let session = NSURLSession.sharedSession()
        let url = NSURL(string: urlString)!
        
        // Make the POST call and handle it in a completion handler
        session.dataTaskWithURL(url, completionHandler: { ( data: NSData?, response: NSURLResponse?, error: NSError?) -> Void in
    
            // Session error
            if error != nil {
                
                completion(json:nil, response:nil, error:error)
                
                return
            }
            
            // Response not usable
            guard let responseActual = response as? NSHTTPURLResponse else {
                
                let error = NSError(domain: "com.jalakoo.resthandler", code:404, userInfo: [NSLocalizedDescriptionKey:"Response from \(urlString) not of type NSHTTPURLReponse.",
                    NSLocalizedFailureReasonErrorKey:"Unexpected Error.",
                    NSLocalizedRecoverySuggestionErrorKey:"Consult a dev."
                    ])
                
                completion(json:nil, response:nil, error:error)
                
                return
            }
            
            // check
            if responseActual.statusCode != 200 {
                
                let error = NSError(domain: "com.jalakoo.resthandler", code:responseActual.statusCode, userInfo: [NSLocalizedDescriptionKey:"Non-200 response returned:\(String(responseActual.statusCode))",
                    NSLocalizedFailureReasonErrorKey:"Undesired response code returned.",
                    NSLocalizedRecoverySuggestionErrorKey:"Try again later or check server at:\(urlString)"
                    ])
                
                completion(json:nil, response:responseActual, error:error)
                
                return
            }
            
            do {

                // Parse JSON
                let jsonDictionary = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as! NSDictionary
                
                completion(json:jsonDictionary, response:responseActual, error:nil)
                
            } catch {
                
                let error = NSError(domain: "com.jalakoo.resthandler", code:400, userInfo: [NSLocalizedDescriptionKey:"Problem parsing data \(data) as JSON.",
                    NSLocalizedFailureReasonErrorKey:"Data was not of type JSON.",
                    NSLocalizedRecoverySuggestionErrorKey:"Check expected response from \(urlString)"
                    ])
                
                completion(json:nil, response:responseActual, error:error)
                
            }
        }).resume()
        
    }