Expose settings API to other handlers.

jupyterlab_server/settings_handler.py

@@ -49,39 +49,6 @@ def _get_schema(schemas_dir, schema_name, overrides):
     return schema
 
 
-def _get_settings(settings_dir, schema_name, schema):
-    """
-    Returns a tuple containing the raw user settings, the parsed user
-    settings, and a validation warning for a schema.
-    """
-
-    path = _path(settings_dir, schema_name, False, SETTINGS_EXTENSION)
-    raw = '{}'
-    settings = dict()
-    warning = ''
-    validation_warning = 'Failed validating settings (%s): %s'
-    parse_error = 'Failed loading settings (%s): %s'
-
-    if os.path.exists(path):
-        with open(path) as fid:
-            try:  # to load and parse the settings file.
-                raw = fid.read() or raw
-                settings = json5.loads(raw)
-            except Exception as e:
-                raise web.HTTPError(500, parse_error % (schema_name, str(e)))
-
-    # Validate the parsed data against the schema.
-    if len(settings):
-        validator = Validator(schema)
-        try:
-            validator.validate(settings)
-        except ValidationError as e:
-            warning = validation_warning % (schema_name, str(e))
-            raw = '{}'
-
-    return (raw, settings, warning)
-
-
 def _get_version(schemas_dir, schema_name):
     """Returns the package version for a given schema or 'N/A' if not found."""
 
@@ -185,51 +152,128 @@ def _path(root_dir, schema_name, make_dirs=False, extension='.json'):
     return path
 
 
-class SettingsHandler(APIHandler):
+def _load_overrides(app_settings_dir):
+    """Load overrides settings from `app_settings_dir`."""
+    overrides_path = os.path.join(app_settings_dir, 'overrides.json')
+    if os.path.exists(overrides_path):
+        with open(overrides_path) as fid:
+            try:
+                overrides = json.load(fid)
+                error = ""
+            except Exception as e:
+                overrides = {}
+                error = e
 
-    def initialize(self, app_settings_dir, schemas_dir, settings_dir):
-        self.overrides = dict()
-        self.schemas_dir = schemas_dir
-        self.settings_dir = settings_dir
+    return overrides, error
 
-        overrides_path = os.path.join(app_settings_dir, 'overrides.json')
-        overrides_warning = 'Failed loading overrides: %s'
 
-        if os.path.exists(overrides_path):
-            with open(overrides_path) as fid:
-                try:
-                    self.overrides = json.load(fid)
-                except Exception as e:
-                    self.log.warn(overrides_warning % str(e))
+def _get_settings(settings_dir, schema_name, schema):
+    """
+    Returns a tuple containing the raw user settings, the parsed user
+    settings, and a validation warning for a schema.
+    """
+    path = _path(settings_dir, schema_name, False, SETTINGS_EXTENSION)
+    raw = '{}'
+    settings = {}
+    warning = ''
+    validation_warning = 'Failed validating settings (%s): %s'
+    parse_error = 'Failed loading settings (%s): %s'
 
-    @web.authenticated
-    def get(self, schema_name=''):
-        overrides = self.overrides
-        schemas_dir = self.schemas_dir
-        settings_dir = self.settings_dir
+    if os.path.exists(path):
+        with open(path) as fid:
+            try:  # to load and parse the settings file.
+                raw = fid.read() or raw
+                settings = json5.loads(raw)
+            except Exception as e:
+                raise web.HTTPError(500, parse_error % (schema_name, str(e)))
 
-        if not schema_name:
-            settings_list, warnings = _list_settings(
-                schemas_dir, settings_dir, overrides)
-            if warnings:
-                self.log.warn('\n'.join(warnings))
-            return self.finish(json.dumps(dict(settings=settings_list)))
+    # Validate the parsed data against the schema.
+    if len(settings):
+        validator = Validator(schema)
+        try:
+            validator.validate(settings)
+        except ValidationError as e:
+            warning = validation_warning % (schema_name, str(e))
+            raw = '{}'
 
+    return (raw, settings, warning)
+
+
+def get_settings(app_settings_dir, schemas_dir, settings_dir, schema_name="", overrides=None):
+    """
+    Get setttings.
+
+    Parameters
+    ----------
+    app_settings_dir:
+        Path to applications settings.
+    schemas_dir: str
+        Path to schemas.
+    settings_dir:
+        Path to settings.
+    schema_name str, optional
+        Schema name. Default is None.
+    overrides: dict, optional
+        Settings overrides. If not provided, the overrides will be loaded
+        from the `app_settings_dir`. Default is None.
+
+    Returns
+    -------
+    tuple
+        The first item is a dictionary with a list of setting if no `schema_name`
+        was provided, otherwise it is a dictionary with id, raw, scheme, settings
+        and version keys. The second item is a list of warnings.
+    """
+    if overrides is None:
+        overrides, _error = _load_overrides(app_settings_dir)
+
+    if schema_name == "":
+        settings_list, warnings = _list_settings(schemas_dir, settings_dir, overrides)
+        result = {
+            "settings": settings_list,
+        }
+    else:
         schema = _get_schema(schemas_dir, schema_name, overrides)
-        raw, settings, warning = _get_settings(
-            settings_dir, schema_name, schema)
+        raw, settings, _warning = _get_settings(settings_dir, schema_name, schema)
         version = _get_version(schemas_dir, schema_name)
+        result = {
+            "id": schema_name,
+            "raw": raw,
+            "schema": schema,
+            "settings": settings,
+            "version": version,
+        }
+        warnings = [_warning]
 
-        if warning:
-            self.log.warn(warning)
+    return result, warnings
 
-        self.finish(json.dumps(dict(
-            id=schema_name,
-            raw=raw,
-            schema=schema,
-            settings=settings,
-            version=version
-        )))
+
+class SettingsHandler(APIHandler):
+
+    def initialize(self, app_settings_dir, schemas_dir, settings_dir):
+        self.overrides, error = _load_overrides(app_settings_dir)
+        self.app_settings_dir = app_settings_dir
+        self.schemas_dir = schemas_dir
+        self.settings_dir = settings_dir
+
+        if error:
+            overrides_warning = 'Failed loading overrides: %s'
+            self.log.warn(overrides_warning % str(error))
+
+    @web.authenticated
+    def get(self, schema_name=""):
+        result, warnings = get_settings(
+            self.app_settings_dir,
+            self.schemas_dir,
+            self.settings_dir,
+            schema_name=schema_name,
+            overrides=self.overrides,
+        )
+
+        if warnings:
+            self.log.warn('\n'.join(warnings))
+
+        return self.finish(json.dumps(result))
 
     @web.authenticated
     def put(self, schema_name):