feat: implement local storage

* feat: propagate local storage into session to keep it into sync

src/writer/app_runner.py

@@ -174,6 +174,7 @@ def _handle_event(self, session: WriterSession, event: WriterEvent) -> EventResp
         import traceback as tb
 
         result = session.event_handler.handle(event)
+        session.process_local_storage_changes()
 
         mutations = {}
 

src/writer/core.py

@@ -139,6 +139,9 @@ class WriterSession:
     """
 
     def __init__(self, session_id: str, cookies: Optional[Dict[str, str]], headers: Optional[Dict[str, str]], local_storage: Optional[Dict[str, Any]]) -> None:
+        if local_storage is None:
+            local_storage = {}
+
         self.session_id = session_id
         self.cookies = cookies
         self.headers = headers
@@ -154,6 +157,19 @@ def __init__(self, session_id: str, cookies: Optional[Dict[str, str]], headers:
     def update_last_active_timestamp(self) -> None:
         self.last_active_timestamp = int(time.time())
 
+    def process_local_storage_changes(self) -> None:
+        """
+        Processes the local storage changes.
+
+        Changes to local storage are propagated by the mail protocol.
+        It process the mail messages to keep the representation of local storage in a consistent session
+        """
+        for m in self.session_state.mail:
+            if m["type"] == "localStorageSetItem":
+                self.local_storage[m['payload']['key']] = m['payload']['value']
+            elif m["type"] == "localStorageRemoveItem":
+                self.local_storage.pop(m['payload']['key'], None)
+
 
 @dataclasses.dataclass
 class MutationSubscription:

tests/backend/test_core.py

@@ -1222,6 +1222,7 @@ def test_get_new_session_proposed(self) -> None:
         self.sm.get_new_session(
             {"testCookie": "yes"},
             {"origin": "example.com"},
+            {},
             self.proposed_session_id
         )
         self.sm.get_session(self.proposed_session_id)