upload method wrapper

AlamofireWrapper.swift

// MARK: MultipartFormData
    
    /**
    Creates an upload request using the shared manager instance for the specified method and URL string.
    
    - parameter method:                  The HTTP method.
    - parameter URLString:               The URL string.
    - parameter headers:                 The HTTP headers. `nil` by default.
    - parameter multipartFormData:       The closure used to append body parts to the `MultipartFormData`.
    - parameter success: Block to be called in case of successful execution of the request.
    - parameter failure: Block to be called in case of errors during the execution of the request.
    */
    public class func upload(
        method: RequestMethod,
        _ URLString: String,
        headers: [String: String]? = nil,
        multipartFormData: (Void -> [BodyPart]),
        success: ((request: NSURLRequest?, response: NSHTTPURLResponse?, json: [NSObject: AnyObject]?) -> ()),
        failure: ((request: NSURLRequest?, response: NSHTTPURLResponse?, error: NSError?) -> ())) {
            let method = translateMethod(method)
            
            Manager.sharedInstance.upload(method, URLString, headers: headers, multipartFormData: { (formData) -> Void in
                let bodyParts = multipartFormData()
                for part in bodyParts {
                    if let fileName = part.fileName, mimeType = part.mimeType {
                        formData.appendBodyPart(data: part.data, name: part.name, fileName: fileName, mimeType: mimeType)
                    } else {
                        formData.appendBodyPart(data: part.data, name: part.name)
                    }
                    
                }
                
                }) { (result) -> Void in
                    switch result {
                    case .Success(let uploadRequest, _, _):
                        uploadRequest.responseData({ (response) -> Void in
                            parseResponse(response, success: success, failure: failure)
                        })
                    case .Failure(_):
                        failure(request: nil, response: nil, error: NSError(domain: "Encoding error", code: 0, userInfo: nil))
                    }
            }
    }