Typed event

CHANGELOG.md

@@ -2,6 +2,13 @@
 
 All notable changes to this project will be documented in this file.
 
+## [1.0.20] - UNRELEASED
+
+### Added
+
+- Added `events` module
+
+
 ## [1.0.19] - 26-11-24
 
 ### Changed

dash_extensions/events.py

@@ -0,0 +1,157 @@
+import datetime
+from enum import Enum
+import re
+from typing import Optional, Type, TypeVar
+from logging import getLogger
+from dash import set_props, ctx
+
+from pydantic import BaseModel, Field
+from dash_extensions.enrich import Input, dcc
+from dash.dependencies import DashDependency
+
+logger = getLogger(__name__)
+
+
+T = TypeVar("T", bound=DashDependency)
+
+
+class EventModel(BaseModel):
+    """
+    The EventModel class provides the main interface for creating and dispatching events.
+    """
+
+    timestamp: float = Field(default_factory=datetime.datetime.now().timestamp)
+
+    def add_listener(self) -> Input:
+        """
+        Listen for event.
+        """
+        return self.get_dependency(Input)
+
+    def dispatch(self):
+        """
+        Dispatch event.
+        """
+        if self._component_id not in _event_registry:
+            logger.warning(f"No listener registered for {self._uid}. Event dispatch suppressed.")
+            return
+        set_props(self._component_id, {"data": self.model_dump()})
+
+    def get_dependency(self, dependency_type: Type[T]) -> T:
+        """
+        Get DashDependency (Input, Output, State) for event.
+        """
+        _register_event(self)  # TODO: Could also be on init?
+        return dependency_type(self._component_id, "data")
+
+    def is_trigger(self) -> bool:
+        return self._component_id in ctx.triggered_prop_ids.values()
+
+    @property
+    def _uid(self) -> str:
+        raise NotImplementedError
+
+    @property
+    def _component_id(self) -> str:
+        return f"event_store_{self._uid}"
+
+
+# region Simple interface (str, Enum; without payload)
+
+
+class SimpleEvent(EventModel):
+    """
+    Wrapper class for simple events.
+    """
+
+    type: str | Enum
+
+    @property
+    def _uid(self) -> str:
+        return _get_event_id(self.type)
+
+
+def _get_event_id(event: str | Enum) -> str:
+    if isinstance(event, Enum):
+        event_tag = event.name.lower()
+        event_type = _to_snake(event.__class__.__name__)
+        return f"{event_type}_{event_tag}"
+    return event
+
+
+def _to_snake(camel: str) -> str:
+    return re.sub(r"(?<!^)(?=[A-Z])", "_", camel).lower()
+
+
+def _base_event(event: str | Enum) -> SimpleEvent:
+    return SimpleEvent(type=event)
+
+
+def dispatch_event(event: str | Enum):
+    """
+    Dispatch an event.
+    """
+    return _base_event(event).dispatch()
+
+
+def get_event_dependency(event: str | Enum, dependency_type: Type[T]) -> T:
+    """
+    Get DashDependency (Input, Output, State) for a particular event type.
+    """
+    return _base_event(event).get_dependency(dependency_type)
+
+
+def add_event_listener(event: str | Enum) -> Input:
+    """
+    Listen for a particular event type.
+    """
+    return _base_event(event).get_dependency(Input)
+
+
+def register_event(event: str | Enum):
+    """
+    Register an event.
+    """
+    _register_event(_base_event(event))
+
+
+def is_event_trigger(event: str | Enum | list[str | Enum]) -> bool:
+    """
+    Check if an event is a trigger of the callback.
+    """
+    events = [event] if not isinstance(event, list) else event
+    return get_event_trigger(events) is not None
+
+
+def get_event_trigger(events: list[str | Enum]) -> Optional[str | Enum]:
+    """
+    Get the event that triggered the callback.
+    """
+    for event in events:
+        if _base_event(event).is_trigger():
+            return event
+    return None
+
+
+# endregion
+
+# region Event registry
+
+
+def resolve_event_components() -> list[dcc.Store]:
+    """
+    Returns the components that must be included in the layout.
+    """
+    return [dcc.Store(id=component_id, storage_type="memory") for component_id in list(_event_registry)]
+
+
+def _register_event(event: EventModel):
+    _event_registry.add(event._component_id)
+
+
+"""
+Registry over all events that have dependencies.
+"""
+_event_registry: set[str] = set()
+
+# endregion

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dash-extensions",
-  "version": "1.0.19",
+  "version": "1.0.20",
   "description": "Extensions for Plotly Dash.",
   "main": "build/index.js",
   "scripts": {

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "dash-extensions"
-version = "1.0.19"
+version = "1.0.20"
 description = "Extensions for Plotly Dash."
 authors = ["emher <emil.h.eriksen@gmail.com>"]
 license = "MIT"