Setting metadata in Bridge

Question

Can someone give some advice on setting metadata values within Bridge using javascript? The examples all seem to deal with Text types like the following:
md = tn.metadata;
md.namespace = "http://ns.adobe.com/photoshop/1.0/";
md.Author = "Jane Smith";
But when trying to set other types, like the "caption" (which gets mapped to "http://purl.org/dc/elements/1.1/description"), the script will throw an exception.
md.namespace = "http://purl.org/dc/elements/1.1/";
md.description = "New Caption"
-- Uncaught exception description --
I'm thinking this is probably because dc:description is defined as a "Lang Alt" type in the xmp specification which in turn is defined as:
"Language alternatives are a form of rdf:Alt array, referred to as the Lang Alt type. In this
example, each array item is a simple text value; the value has a property qualifier, specified as
the property xml:lang, giving the language of that value. "
But no matter how I try accessing this object (there is no "reflect" available on metadata objects), I can't seem to change the string value.
Any ideas would be much appreciated.
On another topic, would it be possible for someone to post the Export Metadata Script here in this forum for those of us who don't have access to the partners site? Here's is my working go at an export metadata script for Bridge that simply prints to the debugger. It's basically a quick hack of some of the routines in AdobeLibrary3.jsx which it also needs in order to run.
Thanks,
Bruce
#target bridge
if( BridgeTalk.appName == "bridge" ) {
DebugMeta = {};
DebugMeta.execute = function() {
// print out the metadata for the selected thumbnails
var sels = app.document.selections;
for (var i = 0; i < sels.length; i++) {
var t = sels[i];
var m = t.synchronousMetadata;
// loop through all possible elements (properties)
var elements = MdNs.elements.keyList;
for (var j = 0; j < elements.length; j++) {
var el = MdNs.elements.get(elements[j]);
if (el.scriptAccessible) {
try {
// print the value (and the mapping if it's redirected)
var val = el.getValue(m);
if ( isValidReference( val )
&& ( val.length > 0 )
&& ( trim( val ) != null ) ) {
$.write(el.handle + " = " + val);
if (el.redirected) {
$.writeln(" (" + el.redirectElement.ns.ns + el.redirectElement.property + ")");
} else {
$.writeln();
} catch (e) {
// setup menu
var myMenu = createMenu( "command", "DebugMeta",
"-at the end of Tools-", "tools/DebugMeta", DebugMeta.execute);
var contextMenu = createMenu ( "command", "DebugMeta",
"-at the end of Thumbnail-", "thumbnail/DebugMeta", DebugMeta.execute);

Answer 1

Bruce,
I think most people here agree with your 2c, but there just wasn't time to do everything.
But one of the great things about Bridge Scripting is, if you don't like it, change it, or create something that will do what you need. If you don't like the way collections work, create your own browse scheme, and do it your way.
The MdNs object has a definition for an object, MdManager. The MdManager constructor takes a thumbnail object. It's "grab" method creates 2 enumerations. MdManager.enumeration contains a KeyedArrayList (object defined in lib3 just above MdNs) of all the metadata elements that actually have values. MdManager.noValue is a KeyedArrayList of metadata elements that do not have values. Now, the standard MdManager only provides checks against the standard XMP schemas. But if you want to extend that, just add a MdNs.MetadataNamespace and the MdNs.MdElement 's necessary to define the non-standard data you want to enumerate.
So while you can't use the metadata object to traverse the metadata structure, there are always other ways.
The concept of modifying the scripting features of Bridge didn't stop there. In Lib1, we extended the File object prototype in Bridge:
File.isFileType() - give it a comma delimited list of extensions, returns true if file matches any of the extensions
File.isPhotoshop() is the file one of "PSD,PDD,8BPS,JPEG,JPG,GIF,"
File.isPageMaker()
File.isInDesign()
File.isPDF()
File.isIllustrator()
File.isOpenableIllustrator()
File.isOpenablePhotoshop()
File.isScript()
File.getExtension( noDecode ) - gets you the extension of the file - noDecode is a boolean - if true it will not perform a decodeURI on the result. Default is false
File.getNameWithoutExtension( noDecode ) - gets you the name of the file without the extension. noDecode is a boolean - if true it will not perform a decodeURI on the result. Default is false
File.getFileWithExtension( ext ) - creates a new File object with the original file name and the provided extension. You provide only the extension ( "jpg" ), the function adds the dot (".jpg").
We also extended the Thumbnail object prototype:
Thumbnail.isFileType( ext ) - same as File.isFileType but for Thumbnails.
Then there's handy functions like:
ensureUniqueFile( file ) - pass it a file object. If the file object exists, it will return a new File object with a "(integer)" added to the filename. So if My Documents/foo.jpg exists, and you called:
ensureUniqueFile( new File( "~/My Documents/foo.jpg ) );
the result would be a file object: My Documents/foo(1).jpg
These next two are defined in lib3:
ensureUniqueFolder( folder ) - does the same thing for a folder
And one of my personal favorites:
verifyFolder( folder, silent ) - if you give it a Folder, it will verify that the folder actually exists, creating the entire path to the folder if necessary. "silent" is a boolean. If true - it will just make the folder (and path to the folder). If false (the default) it will flip up a "Folder does not exist - Do you want to create it" alert to the user, to give them the choice. IF the user opts not to create the folder, it returns undefined.
If My Documents is empty (no files/folders), and you want to write a file into My Documents/1/2/3/My Folder/foo.txt
var f = new File( "~/My Documents/1/2/3/My Folder/foo.txt" );
var folder = verifyFolder( f.parent, true );
f.open( "w" );
f.write( "Four score and seven years ago..." );
f.close();
The result of that ditty will be the successful writing of the file, and the creation of the entire path to the file. It will only create the path elements that do not exist.
Bob
Adobe Workflow Scripting