Update notifications.py

Author: ankit-gautam23

notifications.py

@@ -5,3 +5,24 @@ def handle_connect():
 @socketio.on('disconnect')
 def handle_disconnect():
     print('Client disconnected')
+    
+@socketio.on('subscribe')
+def handle_subscribe():
+    conn.cursor().execute('LISTEN user_changed')
+
+
+CREATE OR REPLACE FUNCTION notify_user_changed()
+RETURNS trigger AS
+$$
+BEGIN
+    PERFORM pg_notify('user_changed', NEW.id::text);
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER user_changed_trigger
+AFTER INSERT OR UPDATE OR DELETE ON users
+FOR EACH ROW
+EXECUTE PROCEDURE notify_user_changed();
+
+