gst module: add configuration and render properties

common/lib/xmodule/xmodule/gst_module.py

@@ -92,6 +92,16 @@ class GraphicalSliderToolModule(GraphicalSliderToolFields, XModule):
     css = {'scss': [resource_string(__name__, 'css/gst/display.scss')]}
     js_module_name = "GraphicalSliderTool"
 
+    @property
+    def configuration(self):
+        return stringify_children(
+            html.fromstring(self.data).xpath('configuration')[0])
+
+    @property
+    def render(self):
+        return stringify_children(
+            html.fromstring(self.data).xpath('render')[0])
+
     def get_html(self):
         """ Renders parameters to template. """
 
@@ -99,12 +109,6 @@ class GraphicalSliderToolModule(GraphicalSliderToolFields, XModule):
         self.html_id = self.location.html_id()
         self.html_class = self.location.category
 
-        self.configuration = html.fromstring(self.data).xpath('configuration')[0]
-        self.configuration = stringify_children(self.configuration)
-
-        self.render = html.fromstring(self.data).xpath('render')[0]
-        self.render = stringify_children(self.render)
-
         self.configuration_json = self.build_configuration_json()
         params = {
             'gst_html': self.substitute_controls(self.render),