"""Plugin for creating and retrieving flash messages."""
from __future__ import annotations
from contextlib import suppress
from dataclasses import dataclass
from typing import TYPE_CHECKING, Any
import litestar.exceptions
from litestar.exceptions import MissingDependencyException
from litestar.middleware import DefineMiddleware
from litestar.middleware.session import SessionMiddleware
from litestar.plugins import InitPlugin
from litestar.security.session_auth.middleware import MiddlewareWrapper
from litestar.template.base import _get_request_from_context
from litestar.utils.predicates import is_class_and_subclass
if TYPE_CHECKING:
from collections.abc import Callable, Mapping
from litestar.config.app import AppConfig
from litestar.connection.base import ASGIConnection
from litestar.template import TemplateConfig
[docs]
@dataclass
class FlashConfig:
"""Configuration for Flash messages."""
template_config: TemplateConfig
[docs]
class FlashPlugin(InitPlugin):
"""Flash messages Plugin."""
[docs]
def __init__(self, config: FlashConfig):
"""Initialize the plugin.
Args:
config: Configuration for flash messages, including the template engine instance.
"""
self.config = config
[docs]
def on_app_init(self, app_config: AppConfig) -> AppConfig:
"""Register the message callable on the template engine instance.
Args:
app_config: The application configuration.
Returns:
The application configuration with the message callable registered.
"""
for mw in app_config.middleware:
if isinstance(mw, DefineMiddleware) and is_class_and_subclass(
mw.middleware, (MiddlewareWrapper, SessionMiddleware)
):
break
else:
raise litestar.exceptions.ImproperlyConfiguredException("Flash messages require a session middleware.")
template_callable: Callable[[Any], Any] = get_flashes
with suppress(MissingDependencyException):
from litestar.contrib.minijinja import MiniJinjaTemplateEngine, _transform_state
if isinstance(self.config.template_config.engine_instance, MiniJinjaTemplateEngine):
template_callable = _transform_state(get_flashes)
self.config.template_config.engine_instance.register_template_callable("get_flashes", template_callable) # pyright: ignore[reportGeneralTypeIssues]
return app_config
def flash(
request: ASGIConnection[Any, Any, Any, Any],
message: Any,
category: str,
) -> None:
request.session.setdefault("_messages", []).append({"message": message, "category": category})
def get_flashes(context: Mapping[str, Any]) -> Any:
return _get_request_from_context(context).session.pop("_messages", [])
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