add support to get localStorage from backend (#2190)

taipy/gui/__init__.py

@@ -78,6 +78,7 @@
 from .gui_actions import (
     broadcast_callback,
     download,
+    get_local_storage,
     get_module_context,
     get_module_name_from_state,
     get_state_id,

taipy/gui/data/data_scope.py

@@ -23,7 +23,8 @@
 class _DataScopes:
     _GLOBAL_ID = "global"
     _META_PRE_RENDER = "pre_render"
-    _DEFAULT_METADATA = {_META_PRE_RENDER: False}
+    _META_LOCAL_STORAGE = "local_storage"
+    _DEFAULT_METADATA = {_META_PRE_RENDER: False, _META_LOCAL_STORAGE: {}}
 
     def __init__(self, gui: "Gui") -> None:
         self.__gui = gui

taipy/gui/gui.py

@@ -691,6 +691,8 @@ def _manage_message(self, msg_type: _WsType, message: dict) -> None:
                         self.__handle_ws_app_id(message)
                     elif msg_type == _WsType.GET_ROUTES.value:
                         self.__handle_ws_get_routes()
+                    elif msg_type == _WsType.LOCAL_STORAGE.value:
+                        self.__handle_ws_local_storage(message)
                     else:
                         self._manage_external_message(msg_type, message)
                 self.__send_ack(message.get("ack_id"))
@@ -1281,6 +1283,27 @@ def __handle_ws_get_routes(self):
             send_back_only=True,
         )
 
+    def __handle_ws_local_storage(self, message: t.Any):
+        if not isinstance(message, dict):
+            return
+        name = message.get("name", "")
+        payload = message.get("payload", None)
+        scope_metadata = self._get_data_scope_metadata()
+        if payload is None:
+            return
+        if name == "init":
+            scope_metadata[_DataScopes._META_LOCAL_STORAGE] = payload
+        elif name == "update":
+            key = payload.get("key", "")
+            value = payload.get("value", None)
+            if value is None:
+                del scope_metadata[_DataScopes._META_LOCAL_STORAGE][key]
+            else:
+                scope_metadata[_DataScopes._META_LOCAL_STORAGE][key] = value
+
+    def _get_local_storage(self):
+        return self._get_data_scope_metadata()[_DataScopes._META_LOCAL_STORAGE]
+
     def __send_ws(self, payload: dict, allow_grouping=True, send_back_only=False) -> None:
         grouping_message = self.__get_message_grouping() if allow_grouping else None
         if grouping_message is None:

taipy/gui/gui_actions.py

@@ -440,3 +440,16 @@ def thread_status(name: str, period_s: float, count: int):
     thread.start()
     if isinstance(period, int) and period >= 500 and callable(user_status_function):
         thread_status(thread.name, period / 1000.0, 0)
+
+
+def get_local_storage(state: State) -> t.Optional[t.Dict[str, str]]:
+    """Get all local storage values
+    Arguments:
+        state (State^): The current user state as received in any callback.
+    Returns:
+        All local storage values
+    """
+    if state and isinstance(state._gui, Gui):
+        return state._gui._get_local_storage()
+    _warn("'get_local_storage()' must be called in the context of a callback.")
+    return None

taipy/gui/types.py

@@ -53,6 +53,7 @@ class _WsType(Enum):
     GET_ROUTES = "GR"
     FAVICON = "FV"
     BROADCAST = "BC"
+    LOCAL_STORAGE = "LS"
 
 
 NumberTypes = {"int", "int64", "float", "float64"}
@@ -158,8 +159,7 @@ class PropertyType(Enum):
 
 
 @t.overload  # noqa: F811
-def _get_taipy_type(a_type: None) -> None:
-    ...
+def _get_taipy_type(a_type: None) -> None: ...
 
 
 @t.overload
@@ -175,8 +175,7 @@ def _get_taipy_type(a_type: PropertyType) -> t.Type[_TaipyBase]:  # noqa: F811
 @t.overload
 def _get_taipy_type(  # noqa: F811
     a_type: t.Optional[t.Union[t.Type[_TaipyBase], t.Type[Decimator], PropertyType]],
-) -> t.Optional[t.Union[t.Type[_TaipyBase], t.Type[Decimator], PropertyType]]:
-    ...
+) -> t.Optional[t.Union[t.Type[_TaipyBase], t.Type[Decimator], PropertyType]]: ...
 
 
 def _get_taipy_type(  # noqa: F811