Add the . into file_extension

IPython/html/nbconvert/handlers.py

@@ -43,7 +43,7 @@ def respond_zip(handler, name, output, resources):
     # Prepare the zip file
     buffer = io.BytesIO()
     zipf = zipfile.ZipFile(buffer, mode='w', compression=zipfile.ZIP_DEFLATED)
-    output_filename = os.path.splitext(name)[0] + '.' + resources['output_extension']
+    output_filename = os.path.splitext(name)[0] + resources['output_extension']
     zipf.writestr(output_filename, cast_bytes(output, 'utf-8'))
     for filename, data in output_files.items():
         zipf.writestr(os.path.basename(filename), data)
@@ -96,7 +96,7 @@ class NbconvertFileHandler(IPythonHandler):
 
         # Force download if requested
         if self.get_argument('download', 'false').lower() == 'true':
-            filename = os.path.splitext(name)[0] + '.' + resources['output_extension']
+            filename = os.path.splitext(name)[0] + resources['output_extension']
             self.set_header('Content-Disposition',
                                'attachment; filename="%s"' % filename)
 

IPython/html/static/notebook/js/menubar.js

@@ -359,7 +359,7 @@ define([
         // Set menu entry text to e.g. "Python (.py)"
         var langname = (langinfo.name || 'Script')
         langname = langname.charAt(0).toUpperCase()+langname.substr(1) // Capitalise
-        el.find('a').text(langname + ' (.'+(langinfo.file_extension || 'txt')+')');
+        el.find('a').text(langname + ' ('+(langinfo.file_extension || 'txt')+')');
         
         // Unregister any previously registered handlers
         el.off('click');

IPython/nbconvert/exporters/python.py

@@ -23,7 +23,7 @@ class PythonExporter(TemplateExporter):
     Exports a Python code file.
     """
     def _file_extension_default(self):
-        return 'py'
+        return '.py'
 
     def _template_file_default(self):
         return 'python'