only use redis if NICEGUI_REDIS_URL is provided as environment variable

nicegui/persistence/file_persistent_dict.py

@@ -3,11 +3,13 @@
 
 import aiofiles
 
-from nicegui import background_tasks, core, json, observables
+from nicegui import background_tasks, core, json
 from nicegui.logging import log
 
+from .persistent_dict import PersistentDict
 
-class FilePersistentDict(observables.ObservableDict):
+
+class FilePersistentDict(PersistentDict):
 
     def __init__(self, filepath: Path, encoding: Optional[str] = None, *, indent: bool = False) -> None:
         self.filepath = filepath

nicegui/persistence/persistent_dict.py

@@ -0,0 +1,11 @@
+
+from nicegui import observables
+
+
+class PersistentDict(observables.ObservableDict):
+
+    async def initialize(self) -> None:
+        """Load initial data from the persistence layer."""
+
+    async def close(self) -> None:
+        """Clean up the persistence layer."""

nicegui/persistence/redis_persistent_dict.py

@@ -1,12 +1,14 @@
 import redis.asyncio as redis
 
-from nicegui import background_tasks, core, json, observables
+from nicegui import background_tasks, core, json
 from nicegui.logging import log
 
+from .persistent_dict import PersistentDict
 
-class RedisPersistentDict(observables.ObservableDict):
 
-    def __init__(self, redis_url: str = 'redis://localhost:6379', key_prefix: str = 'nicegui:', encoding: str = 'utf-8') -> None:
+class RedisPersistentDict(PersistentDict):
+
+    def __init__(self, redis_url: str, key_prefix: str = 'nicegui:', encoding: str = 'utf-8') -> None:
         self.redis_client = redis.from_url(redis_url)
         self.pubsub = self.redis_client.pubsub()
         self.key_prefix = key_prefix

nicegui/storage.py

@@ -53,9 +53,13 @@ class Storage:
 
     def __init__(self) -> None:
         self.path = Path(os.environ.get('NICEGUI_STORAGE_PATH', '.nicegui')).resolve()
+        """Path to use for local persistence. Defaults to '.nicegui'."""
         self.max_tab_storage_age: float = timedelta(days=30).total_seconds()
         """Maximum age in seconds before tab storage is automatically purged. Defaults to 30 days."""
-        self._general = RedisPersistentDict()  # PersistentDict(self.path / 'storage-general.json', encoding='utf-8')
+        self.redis_url = os.environ.get('NICEGUI_REDIS_URL', None)
+        """URL to use for shared persistent storage via Redis. Defaults to None, which means local file storage is used."""
+        self._general = RedisPersistentDict(self.redis_url) if self.redis_url \
+            else FilePersistentDict(self.path / 'storage-general.json', encoding='utf-8')
         self._users: Dict[str, FilePersistentDict] = {}
         self._tabs: Dict[str, observables.ObservableDict] = {}