feat: dont download notebook if not necessary

public/script/app.js

@@ -415,18 +415,26 @@ angular
         restrict: "E",
         scope: { file: "=" },
         controller: function ($element, $scope, $http) {
-          function render() {
+          function renderNotebookJSON(json) {
-            if (!$scope.file) return;
+            $element.html("");
-            $http.get($scope.file).then((res) => {
+            const notebook = nb.parse(json);
-              var notebook = nb.parse(res.data);
             try {
-                var rendered = notebook.render();
+              const rendered = notebook.render();
               $element.append(rendered);
               Prism.highlightAll();
             } catch (error) {
               $element.html("Unable to render the notebook.");
             }
-            });
+          }
+          function render() {
+            // $element.html("");
+            if ($scope.$parent.content) {
+              renderNotebookJSON(JSON.parse($scope.$parent.content));
+            } else if ($scope.file) {
+              $http
+                .get($scope.file.download_url)
+                .then((res) => renderNotebookJSON(res.data));
+            }
           }
           $scope.$watch("file", (v) => {
             render();