Get mime/type from MediaPromise - actionscript-3

Question

I am trying to make my scrips as cross-platform as possible. I am using CameraUI to fetch files and upload them to Firebase. The problem is I can only get the bytearray through the filepromise and not the file extension..or anything. According to numerous guides iOS wont let you get mediaPromise.file to get it's type. So I'm left with the question of how to get a mime/type from this bytearray I have, that I know is either an image or a video from MediaPromise.type.
MetaData or anything would help.
Following this guide gets me to a security error. Something with domains. I'm in Android and iOS so I can't do Security.allowDomain("*"); I made my own version by following this guide.
I searched and found this guide, and this works. But it only fetches the bytearray..
He wrote another article that made something that extracted data from the first 64K of the bytearray or something and displayed it in his app. He used a lib that's no longer up so I can't really go with his guide.
The code in there is the code I have in my script aside from a few UI management additions. How would I go about solving this? Is there some meta-data that always lies in the first set of bytes?
I even tried using this nice ANE, but I get an error..

Answer 1

You can get the mime type once the mediapromise was loaded:
cameraUI = new CameraUI();
if (CameraUI.isSupported)
{
cameraUI.addEventListener(MediaEvent.COMPLETE, onCameraUIComplete);
cameraUI.addEventListener(Event.CANCEL, onCameraUICanceled);
cameraUI.addEventListener(ErrorEvent.ERROR, onCameraError);
cameraUI.launch(MediaType.IMAGE);
}
private function onCameraUIComplete(e:MediaEvent):void
{
var mediaPromise:MediaPromise = e.data;
if (mediaPromise)
{
myLoader = new Loader();
myLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, onMediaPromiseLoaded);
myLoader.addEventListener(IOErrorEvent.IO_ERROR, onMediaPromiseLoadError);
myLoader.loadFilePromise(mediaPromise);
}
}
private function onMediaPromiseLoaded(e:Event):void
{
var myLoaderInfo:LoaderInfo = e.target as LoaderInfo;
var myByteArray:ByteArray = myLoaderInfo.bytes;
var mimeType:String = myLoaderInfo.contentType;
}
Another way is to determine the mimetype "manually" based on the file extension in mediaPromise.file.extension