Refactor: Use type[Event] instead of str to filter events (#6480)

Co-authored-by: openhands <openhands@all-hands.dev>

openhands/events/stream.py

@@ -319,7 +319,7 @@ class EventStream:
         self,
         event,
         query: str | None = None,
-        event_type: str | None = None,
+        event_type: type[Event] | None = None,
         source: str | None = None,
         start_date: str | None = None,
         end_date: str | None = None,
@@ -329,7 +329,7 @@ class EventStream:
         Args:
             event: The event to check
             query (str, optional): Text to search for in event content
-            event_type (str, optional): Filter by event type (e.g., "FileReadAction")
+            event_type (type[Event], optional): Filter by event type class (e.g., FileReadAction)
             source (str, optional): Filter by event source
             start_date (str, optional): Filter events after this date (ISO format)
             end_date (str, optional): Filter events before this date (ISO format)
@@ -337,7 +337,7 @@ class EventStream:
         Returns:
             bool: True if the event should be filtered out, False if it matches all criteria
         """
-        if event_type and not event.__class__.__name__ == event_type:
+        if event_type and not isinstance(event, event_type):
             return True
 
         if source and not event.source.value == source:
@@ -361,7 +361,7 @@ class EventStream:
     def get_matching_events(
         self,
         query: str | None = None,
-        event_type: str | None = None,
+        event_type: type[Event] | None = None,
         source: str | None = None,
         start_date: str | None = None,
         end_date: str | None = None,
@@ -372,7 +372,7 @@ class EventStream:
 
         Args:
             query (str, optional): Text to search for in event content
-            event_type (str, optional): Filter by event type (e.g., "FileReadAction")
+            event_type (type[Event], optional): Filter by event type class (e.g., FileReadAction)
             source (str, optional): Filter by event source
             start_date (str, optional): Filter events after this date (ISO format)
             end_date (str, optional): Filter events before this date (ISO format)

openhands/server/routes/conversation.py

@@ -2,11 +2,26 @@ from fastapi import APIRouter, HTTPException, Request, status
 from fastapi.responses import JSONResponse
 
 from openhands.core.logger import openhands_logger as logger
+from openhands.events.event import Event
+from openhands.events.serialization.event import event_from_dict
 from openhands.runtime.base import Runtime
 
 app = APIRouter(prefix='/api/conversations/{conversation_id}')
 
 
+def str_to_event_type(event: str | None) -> Event | None:
+    if not event:
+        return None
+
+    for event_type in ['observation', 'action']:
+        try:
+            return event_from_dict({event_type: event})
+        except Exception:
+            continue
+
+    return None
+
+
 @app.get('/config')
 async def get_remote_runtime_config(request: Request):
     """Retrieve the runtime configuration.
@@ -126,9 +141,11 @@ async def search_events(
         )
     # Get matching events from the stream
     event_stream = request.state.conversation.event_stream
+
+    cast_event_type = str_to_event_type(event_type)
     matching_events = event_stream.get_matching_events(
         query=query,
-        event_type=event_type,
+        event_type=cast_event_type,
         source=source,
         start_date=start_date,
         end_date=end_date,

tests/unit/test_event_stream.py

@@ -74,12 +74,12 @@ def test_get_matching_events_type_filter(temp_dir: str):
     event_stream.add_event(NullAction(), EventSource.AGENT)
 
     # Filter by NullAction
-    events = event_stream.get_matching_events(event_type='NullAction')
+    events = event_stream.get_matching_events(event_type=NullAction)
     assert len(events) == 2
     assert all(e['action'] == 'null' for e in events)
 
     # Filter by NullObservation
-    events = event_stream.get_matching_events(event_type='NullObservation')
+    events = event_stream.get_matching_events(event_type=NullObservation)
     assert len(events) == 1
     assert events[0]['observation'] == 'null'