Swift如何修改从移动相机拍摄的图像中的exif信息

我曾经UIImagePickerController在我的iOS应用程序中选择图像，我知道exif信息可以通过获取info[UIImagePickerControllerMediaMetadata]。但是，当我通过上载我的图像到服务器时UIImage，大多数exif信息已被分割。我想知道是否可以在Http请求中将exif信息添加到我的图像中（此后以jpg格式上传的图像）。如果没有，我应该如何解决这个问题？我想更改“制作”，“模型”属性（换句话说，使用什么设备拍摄这张照片）

以下是我的代码段：

func Tapped() {
    let myPickerController = UIImagePickerController()

    myPickerController.delegate = self
    myPickerController.sourceType = UIImagePickerControllerSourceType.Camera
    myPickerController.allowsEditing = false
    self.presentViewController(myPickerController, animated: true, completion: nil)
}
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
    let image = info[UIImagePickerControllerOriginalImage] as? UIImage
    myImageView.image = image
    UIImageWriteToSavedPhotosAlbum(image!, self, #selector(ViewController.image(_:didFinishSavingWithError:contextInfo:)), nil)
    self.dismissViewControllerAnimated(true, completion: nil)
}

func myImageUploadRequest()
{

    let myUrl = NSURL(string: "http://XXXXXX/Uploadfile")

    let request = NSMutableURLRequest(URL:myUrl!)
    request.HTTPMethod = "POST"

    let param = [
        "userId"    : "7"
    ]

    let boundary = generateBoundaryString()

    request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")


    let imageData = UIImageJPEGRepresentation(myImageView.image!, 1)

    if(imageData == nil)  { return; }

    request.HTTPBody = createBodyWithParameters(param, filePathKey: "file", imageDataKey: imageData!, boundary: boundary)



    myActivityIndicator.startAnimating()

    let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {
        data, response, error in

        if error != nil {
            print("error=\(error)")
            return
        }

        // You can print out response object
        print("******* response = \(response)")

        // Print out response body
        let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding)
        print("****** response data = \(responseString!)")

        do{
            let json = try NSJSONSerialization.JSONObjectWithData(data!, options: .MutableContainers) as? NSDictionary

        }catch{
            print(error)
        }


        dispatch_async(dispatch_get_main_queue(),{
            self.myActivityIndicator.stopAnimating()
            self.myImageView.image = nil
        })

    }

    task.resume()
}

func createBodyWithParameters(parameters: [String: String]?, filePathKey: String?, imageDataKey: NSData, boundary: String) -> NSData {
    let body = NSMutableData();

    if parameters != nil {
        for (key, value) in parameters! {
            body.appendString("--\(boundary)\r\n")
            body.appendString("Content-Disposition: form-data; name=\"\(key)\"\r\n\r\n")
            body.appendString("\(value)\r\n")
        }
    }

    let filename = "test.jpg"

    let mimetype = "image/jpg"

    body.appendString("--\(boundary)\r\n")
    body.appendString("Content-Disposition: form-data; name=\"\(filePathKey!)\"; filename=\"\(filename)\"\r\n")
    body.appendString("Content-Type: \(mimetype)\r\n\r\n")
    body.appendData(imageDataKey)
    body.appendString("\r\n")



    body.appendString("--\(boundary)--\r\n")

    return body
}

func generateBoundaryString() -> String {
    return "Boundary-\(NSUUID().UUIDString)"
}

extension NSMutableData {
    func appendString(string: String) {
        let data = string.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)
        appendData(data!)
    }
}