change rule and event handle

nonebot/message.py

@@ -1,19 +1,39 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
+import asyncio
+from typing import Set, Callable
+
 from nonebot.log import logger
 from nonebot.event import Event
 from nonebot.matcher import matchers
+from nonebot.exception import IgnoredException
+
+_event_preprocessors: Set[Callable] = set()
+
+
+def event_preprocessor(func: Callable) -> Callable:
+    _event_preprocessors.add(func)
+    return func
 
 
 async def handle_event(bot, event: Event):
     # TODO: PreProcess
+    coros = []
+    for preprocessor in _event_preprocessors:
+        coros.append(preprocessor(bot, event))
+    if coros:
+        try:
+            await asyncio.gather(*coros)
+        except IgnoredException:
+            logger.info(f"Event {event} is ignored")
+            return
 
     for priority in sorted(matchers.keys()):
         for index in range(len(matchers[priority])):
             Matcher = matchers[priority][index]
             try:
-                if not Matcher.check_rule(event):
+                if not Matcher.check_rule(bot, event):
                     continue
             except Exception as e:
                 logger.error(