using XMPCore to get metadata of a file through actionscript

Question

Is there a simple example to read/write metadata of e.g. a local .jpg? XMPCore ActionScript Reference

Unfortunately I was not able to apply the instructions from adobe.

A simple example will help me a lot! Thanks

Answer 1

I've written a small snippet on the matter. this snippet is far from being proper tested, and is most definite not written in a clear and coherent way. But for now it seems to work. I'll update as I work on it.

From http://snipplr.com/view/51037/xmp-metadata-from-jpg/

private function init(event:Event):void
{
    var ldr:Loader = new Loader();
    ldr.contentLoaderInfo.addEventListener(Event.COMPLETE, imgLoaded);
    var s:String = "link/to/asset.jpg";
    ldr.load(new URLRequest(s));
}
private function imgLoaded(e:Event):void{
    var info:LoaderInfo = e.target as LoaderInfo;
    var xmpXML:XML = getXMP(info.bytes);

    //trace(xmpXML);
    var meta:XMPMeta = new XMPMeta(xmpXML);
}
private function trim(s:String):String{
    return s.replace( /^([\s|\t|\n]+)?(.*)([\s|\t|\n]+)?$/gm, "$2" );
}
private function getXMP(ba:ByteArray):XML{
        var LP:ByteArray = new ByteArray();
    var PACKET:ByteArray = new ByteArray();
    var l:int;

    ba.readBytes(LP, 2, 2);
    /* 
    http://www.adobe.com/devnet/xmp.html
    read part 3: Storage in Files.

    that will explain the -2 -29 and other things you see here.
     */
    l = LP.readInt() - 2 -29;
    ba.readBytes(PACKET, 33, l);

    var p:String = trim(""+PACKET);
    var i:int = p.search('<x:xmpmeta xmlns:x="adobe:ns:meta/"');
    /* Delete all in front of the XMP XML */
    p = p.substr(i);
    /* 
    For some reason this left some rubbish in front, so I'll hardcode it out for now 

    TODO clean up
    */

    var ar:Array = p.split('<');
    var s:String = "";
    var q:int;
    var j:int = ar.length;
    for(q=1;q<j;q++){
        s += '<'+ar[q];
    }
    i = s.search('</x:xmpmeta>');
    i += ('</x:xmpmeta>').length;
    s = s.slice(0,i);
    /* Delete all behind the XMP XML */
    return XML(s);
}