Add metadata support to JavaScript dataset objects.

static/scripts/mvc/data.js

@@ -1,5 +1,10 @@
 define(["libs/backbone/backbone-relational"], function() {
 
+/**
+ * Dataset metedata.
+ */
+var DatasetMetadata = Backbone.RelationalModel.extend({});
+
 /**
  * A dataset. In Galaxy, datasets are associated with a history, so
  * this object is also known as a HistoryDatasetAssociation.
@@ -9,7 +14,33 @@ var Dataset = Backbone.RelationalModel.extend({
         id: '',
         type: '',
         name: '',
-        hda_ldda: 'hda'
+        hda_ldda: 'hda',
+        metadata: null
+    },
+
+    initialize: function() {
+        // -- Create and initialize metadata. -- 
+
+        var metadata = new DatasetMetadata();
+
+        // Move metadata from dataset attributes to metadata object.
+        _.each(_.keys(this.attributes), function(k) { 
+            if (k.indexOf('metadata_') === 0) {
+                // Found metadata.
+                var new_key = k.split('metadata_')[1];
+                metadata.set(new_key, this.attributes[k]);
+                delete this.attributes[k];
+            }
+        }, this);
+
+        this.set('metadata', metadata);
+    },
+
+    /**
+     * Returns dataset metadata for a given attribute.
+     */
+    get_metadata: function(attribute) {
+        return this.attributes.metadata.get(attribute);
     },
 
     urlRoot: galaxy_paths.get('datasets_url')