Remove leading "/" from preferred_dir

Also validates set value to strip any leading slashes

Author: vidartf

jupyter_server/services/contents/filemanager.py

@@ -68,16 +68,16 @@ def _default_preferred_dir(self):
         else:
             if value is not None:
                 warnings.warn(
-                    "ServerApp.preferred_dir config is deprecated in jupyter-server 2.0. Use ContentsManager.preferred_dir with a relative path instead",
+                    "ServerApp.preferred_dir config is deprecated in jupyter-server 2.0. Use FileContentsManager.preferred_dir instead",
                     FutureWarning,
                     stacklevel=3,
                 )
                 try:
                     path = Path(value)
-                    return "/" + path.relative_to(self.root_dir).as_posix()
+                    return path.relative_to(self.root_dir).as_posix()
                 except ValueError:
                     raise TraitError("%s is outside root contents directory" % value)
-        return "/"
+        return ""
 
     @default("checkpoints_class")
     def _checkpoints_class_default(self):

jupyter_server/services/contents/manager.py

@@ -66,16 +66,16 @@ def emit(self, data):
     root_dir = Unicode("/", config=True)
 
     preferred_dir = Unicode(
-        "/",
+        "",
         config=True,
         help=_i18n(
-            "Preferred starting directory to use for notebooks, relative to the server root dir."
+            "Preferred starting directory to use for notebooks. This is an API path (`/` separated, relative to root dir)"
         ),
     )
 
     @validate("preferred_dir")
     def _validate_preferred_dir(self, proposal):
-        value = proposal["value"]
+        value = proposal["value"].strip("/")
         try:
             dir_exists = run_sync(self.dir_exists)(value)
         except HTTPError as e:

tests/test_serverapp.py

@@ -271,7 +271,7 @@ def test_valid_preferred_dir(tmp_path, jp_configurable_serverapp):
     assert app.preferred_dir == path
     assert app.root_dir == app.preferred_dir
     assert app.contents_manager.root_dir == path
-    assert app.contents_manager.preferred_dir == "/"
+    assert app.contents_manager.preferred_dir == ""
 
 
 @pytest.mark.filterwarnings("ignore::FutureWarning")
@@ -283,7 +283,7 @@ def test_valid_preferred_dir_is_root_subdir(tmp_path, jp_configurable_serverapp)
     assert app.root_dir == path
     assert app.preferred_dir == path_subdir
     assert app.preferred_dir.startswith(app.root_dir)
-    assert app.contents_manager.preferred_dir == "/subdir"
+    assert app.contents_manager.preferred_dir == "subdir"
 
 
 def test_valid_preferred_dir_does_not_exist(tmp_path, jp_configurable_serverapp):
@@ -332,8 +332,9 @@ def test_preferred_dir_validation(
 
     os_preferred_dir = str(tmp_path / "subdir")
     os.makedirs(os_preferred_dir, exist_ok=True)
-    config_preferred_dir = os_preferred_dir if config_target == "ServerApp" else "/subdir"
-    expected_preferred_dir = "/subdir"
+    config_preferred_dir = os_preferred_dir if config_target == "ServerApp" else "subdir"
+    config_preferred_dir = config_preferred_dir + "/"  # add trailing slash to ensure it is removed
+    expected_preferred_dir = "subdir"
 
     argv = []
     kwargs = {"root_dir": None}
@@ -355,7 +356,7 @@ def test_preferred_dir_validation(
     if preferred_dir_loc == "config":
         config_lines.append(f'c.{config_target}.preferred_dir = r"{config_preferred_dir}"')
     if preferred_dir_loc == "default":
-        expected_preferred_dir = "/"
+        expected_preferred_dir = ""
 
     if config_file is not None:
         config_file.write_text("\n".join(config_lines))