use RFC5987 encoding for filenames

as described in RFC 6266 describing Content-Disposition

notebook/base/handlers.py

@@ -279,6 +279,20 @@ class IPythonHandler(AuthenticatedHandler):
         if self.allow_credentials:
             self.set_header("Access-Control-Allow-Credentials", 'true')
     
+    def set_attachment_header(self, filename):
+        """Set Content-Disposition: attachment header
+
+        As a method to ensure handling of filename encoding
+        """
+        escaped_filename = url_escape(filename)
+        self.set_header('Content-Disposition',
+            'attachment;'
+            " filename*=utf-8''{utf8}"
+            .format(
+                utf8=escaped_filename,
+            )
+        )
+
     def get_origin(self):
         # Handle WebSocket Origin naming convention differences
         # The difference between version 8 and 13 is that in 8 the
@@ -478,7 +492,7 @@ class AuthenticatedFileHandler(IPythonHandler, web.StaticFileHandler):
     def get(self, path):
         if os.path.splitext(path)[1] == '.ipynb' or self.get_argument("download", False):
             name = path.rsplit('/', 1)[-1]
-            self.set_header('Content-Disposition','attachment; filename="%s"' % name)
+            self.set_attachment_header(name)
 
         return web.StaticFileHandler.get(self, path)
     

notebook/bundler/tarball_bundler.py

@@ -39,10 +39,9 @@ def bundle(handler, model):
     with io.BytesIO() as tar_buffer:
         with tarfile.open(tar_filename, "w:gz", fileobj=tar_buffer) as tar:
             tar.addfile(info, io.BytesIO(notebook_content))
-        
-        handler.set_header('Content-Disposition',
-                           'attachment; filename="{}"'.format(tar_filename))
+
+        handler.set_attachment_header(tar_filename)
         handler.set_header('Content-Type', 'application/gzip')
-                
+
         # Return the buffer value as the response
         handler.finish(tar_buffer.getvalue())

notebook/bundler/zip_bundler.py

@@ -35,8 +35,7 @@ def bundle(handler, model):
 
     # Headers
     zip_filename = os.path.splitext(notebook_name)[0] + '.zip'
-    handler.set_header('Content-Disposition',
-                       'attachment; filename="%s"' % zip_filename)
+    handler.set_attachment_header(zip_filename)
     handler.set_header('Content-Type', 'application/zip')
 
     # Get associated files

notebook/files/handlers.py

@@ -46,7 +46,7 @@ class FilesHandler(IPythonHandler):
         model = cm.get(path, type='file', content=include_body)
         
         if self.get_argument("download", False):
-            self.set_header('Content-Disposition','attachment; filename="%s"' % name)
+            self.set_attachment_header(name)
         
         # get mimetype from filename
         if name.endswith('.ipynb'):

notebook/nbconvert/handlers.py

@@ -38,8 +38,7 @@ def respond_zip(handler, name, output, resources):
 
     # Headers
     zip_filename = os.path.splitext(name)[0] + '.zip'
-    handler.set_header('Content-Disposition',
-                       'attachment; filename="%s"' % zip_filename)
+    handler.set_attachment_header(zip_filename)
     handler.set_header('Content-Type', 'application/zip')
 
     # Prepare the zip file
@@ -114,8 +113,7 @@ class NbconvertFileHandler(IPythonHandler):
         # Force download if requested
         if self.get_argument('download', 'false').lower() == 'true':
             filename = os.path.splitext(name)[0] + resources['output_extension']
-            self.set_header('Content-Disposition',
-                               'attachment; filename="%s"' % filename)
+            self.set_attachment_header(filename)
 
         # MIME type
         if exporter.output_mimetype:

notebook/tests/test_files.py

@@ -112,7 +112,7 @@ class FilesTest(NotebookTestBase):
         r = self.request('GET', 'files/test.txt?download=1')
         disposition = r.headers.get('Content-Disposition', '')
         self.assertIn('attachment', disposition)
-        self.assertIn('filename="test.txt"', disposition)
+        self.assertIn("filename*=utf-8''test.txt", disposition)
         
     def test_view_html(self):
         nbdir = self.notebook_dir