Merge pull request #49 from open-ephys/development

Add callable stop flag to `EventListener` class

Author: jsiegle

src/open_ephys/__init__.py

@@ -1 +1 @@
-__version__ = "1.0.0"
+__version__ = "1.0.1"

src/open_ephys/streaming/README.md

@@ -85,3 +85,30 @@ stream.start(ttl_callback=ttl_callback,
 
 To stop listening, press `ctrl-C`.
 
+
+### Running the event listener in a separate thread
+
+To receive and respond to events in a separate thread, you can use the Python `threading` library:
+
+```python
+import threading
+from open_ephys.streaming import EventListener
+
+stream = EventListener(port=5557)
+
+thread = threading.Thread(
+            target = stream.start, 
+            args = (ttl_callback, spike_callback), # Arguments to the target function
+            daemon = True # Ensures the main program doesn't exit when the thread finishes
+        )
+
+thread.start()
+```
+
+To stop listening, call the `EventListener.stop()` method, and allow the thread to shut down gracefully by calling `thread.join()`:
+
+```python
+stream.stop()
+thread.join()
+```
+

src/open_ephys/streaming/event_listener.py

@@ -24,6 +24,7 @@
 
 import zmq
 import json
+import threading
 
 
 def default_spike_callback(info):
@@ -99,6 +100,8 @@ def __init__(self, ip_address="127.0.0.1", port=5557):
         self.socket = self.context.socket(zmq.SUB)
         self.socket.connect(self.url)
         self.socket.setsockopt(zmq.SUBSCRIBE, b"")
+        self.socket.setsockopt(zmq.RCVTIMEO, 1000) # 1 second timeout
+        self._stop_event = threading.Event()        
 
         print("Initialized EventListener at " + self.url)
 
@@ -120,8 +123,9 @@ def start(
         """
 
         print("Starting EventListener")
+        self._stop_event.clear()  # Clear stop event
 
-        while True:
+        while not self._stop_event.is_set():
             try:
                 parts = self.socket.recv_multipart()
 
@@ -133,7 +137,18 @@ def start(
                         spike_callback(info)
                     else:
                         ttl_callback(info)
-
+            except zmq.Again:
+                # Timeout occurred, continue loop to check stop flag
+                continue
             except KeyboardInterrupt:
-                print()  # Add final newline
+                print("Stopped by KeyboardInterrupt")
+                break
+            except Exception as e:
+                print(f"Error: {e}")
                 break
+
+        print("EventListener stopped")
+
+    def stop(self):
+        """Call this method to stop the listener"""
+        self._stop_event.set()