make websocket server to send ping frame to client

CHANGELOG.md

@@ -1,5 +1,13 @@
 ## CHANGELOG
 
+### `jupyter-lsp 1.0.1` (unreleased)
+
+- bug fixes:
+
+  - send periodic pings on websocket channels to maintain connection ([#459], thanks @franckchen)
+
+[#459]: https://github.com/krassowski/jupyterlab-lsp/pull/459
+
 ### `@krassowski/jupyterlab-lsp 3.0.0` (2021-01-06)
 
 - features

python_packages/jupyter_lsp/jupyter_lsp/handlers.py

@@ -26,6 +26,7 @@ def open(self, language_server):
         self.language_server = language_server
         self.manager.subscribe(self)
         self.log.debug("[{}] Opened a handler".format(self.language_server))
+        super().open()
 
     async def on_message(self, message):
         self.log.debug("[{}] Handling a message".format(self.language_server))

python_packages/jupyter_lsp/jupyter_lsp/tests/conftest.py

@@ -5,7 +5,9 @@
 
 from jupyter_server.serverapp import ServerApp
 from pytest import fixture
+from tornado.httputil import HTTPServerRequest
 from tornado.queues import Queue
+from tornado.web import Application
 
 # local imports
 from jupyter_lsp import LanguageServerManager
@@ -87,18 +89,24 @@ def app():
 # mocks
 class MockWebsocketHandler(LanguageServerWebSocketHandler):
     _messages_wrote = None  # type: Queue
+    _ping_sent = None  # type: bool
 
     def __init__(self):
-        pass
+        self.request = HTTPServerRequest()
+        self.application = Application()
 
     def initialize(self, manager):
         super().initialize(manager)
         self._messages_wrote = Queue()
+        self._ping_sent = False
 
     def write_message(self, message: Text) -> None:
         self.log.warning("write_message %s", message)
         self._messages_wrote.put_nowait(message)
 
+    def send_ping(self):
+        self._ping_sent = True
+
 
 class MockHandler(LanguageServersHandler):
     _payload = None

python_packages/jupyter_lsp/jupyter_lsp/tests/test_session.py

@@ -70,3 +70,30 @@ async def test_start_unknown(known_unknown_server, handlers, jsonrpc_init_msg):
 
     assert not manager.sessions.get(ws_handler.language_server)
     assert_status_set(handler, {"not_started"})
+
+
+@pytest.mark.asyncio
+async def test_ping(handlers):
+    """see https://github.com/krassowski/jupyterlab-lsp/issues/458"""
+    a_server = "pyls"
+
+    handler, ws_handler = handlers
+    manager = handler.manager
+
+    manager.initialize()
+
+    assert ws_handler.ping_interval > 0
+    # the default ping interval is 30 seconds, too long for a test
+    ws_handler.settings["ws_ping_interval"] = 0.1
+    assert ws_handler.ping_interval == 0.1
+
+    assert ws_handler._ping_sent is False
+
+    ws_handler.open(a_server)
+
+    assert ws_handler.ping_callback is not None and ws_handler.ping_callback.is_running
+    await asyncio.sleep(ws_handler.ping_interval * 3)
+
+    assert ws_handler._ping_sent is True
+
+    ws_handler.on_close()