fix(jupyter): Catching validation error in order to avoid app crash ic case of formatting issues. Fixes: RCCE-26

rhodecode/lib/markup_renderer.py

@@ -538,10 +538,20 b' class MarkupRenderer(object):'
             body = '\n'.join([header, css, js, body])
             return body, resources
 
-        # TODO: In the event of a newer jupyter notebook version, consider increasing the as_version parameter
-        notebook = nbformat.reads(source, as_version=4)
-        (body, resources) = as_html(notebook)
-        return body
+            captured_errors = {}
+            # TODO: In the event of a newer jupyter notebook version, consider increasing the as_version parameter
+            notebook = nbformat.reads(source, as_version=4, capture_validation_error=captured_errors)
+            try:
+                (body, resources) = as_html(notebook)
+            except AttributeError:
+                error_messages = '<br>'.join(str(error) for error in captured_errors.values())
+                body = f"""
+                        <div style="text-align: center;">
+                            <h3>Invalid Notebook!</h3>
+                            <p>{error_messages}</p>
+                        </div>
+                    """
+            return body
 
 
 class RstTemplateRenderer(object):