Minor fixes (#991)

* Minor fixes

* verify port before starting

src/taipy/gui/gui.py

@@ -1629,9 +1629,11 @@ def _broadcast(self, name: str, value: t.Any):
         self.__send_ws_broadcast(name, value)
 
     def _broadcast_all_clients(self, name: str, value: t.Any):
-        self._set_broadcast()
-        self._update_var(name, value)
-        self._set_broadcast(False)
+        try:
+            self._set_broadcast()
+            self._update_var(name, value)
+        finally:
+            self._set_broadcast(False)
 
     def _set_broadcast(self, broadcast: bool = True):
         with contextlib.suppress(RuntimeError):

src/taipy/gui/server.py

@@ -16,7 +16,6 @@
 import os
 import pathlib
 import re
-import socket
 import sys
 import time
 import typing as t
@@ -36,7 +35,7 @@
 
 from ._renderers.json import _TaipyJsonProvider
 from .config import ServerConfig
-from .utils import _is_in_notebook, _RuntimeManager
+from .utils import _is_in_notebook, _is_port_open, _RuntimeManager
 from .utils.proxy import NotebookProxy
 
 if t.TYPE_CHECKING:
@@ -237,12 +236,6 @@ def _run_notebook(self):
     def _get_async_mode(self) -> str:
         return self._ws.async_mode
 
-    def _is_port_open(self, host, port) -> bool:
-        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        result = sock.connect_ex((host, port))
-        sock.close()
-        return result == 0
-
     def _apply_patch(self):
         if self._get_async_mode() == "gevent" and util.find_spec("gevent"):
             from gevent import monkey
@@ -258,7 +251,7 @@ def _apply_patch(self):
     def _get_random_port(self):  # pragma: no cover
         while True:
             port = randint(49152, 65535)
-            if port not in _RuntimeManager().get_used_port() and not self._is_port_open(self._host, port):
+            if port not in _RuntimeManager().get_used_port() and not _is_port_open(self._host, port):
                 return port
 
     def run(self, host, port, debug, use_reloader, flask_log, run_in_thread, allow_unsafe_werkzeug, notebook_proxy):
@@ -273,7 +266,7 @@ def run(self, host, port, debug, use_reloader, flask_log, run_in_thread, allow_u
         if _is_in_notebook() or run_in_thread:
             runtime_manager = _RuntimeManager()
             runtime_manager.add_gui(self._gui, port)
-        if debug and not is_running_from_reloader() and self._is_port_open(host_value, port):
+        if debug and not is_running_from_reloader() and _is_port_open(host_value, port):
             raise ConnectionError(
                 f"Port {port} is already opened on {host_value}. You have another server application running on the same port."
             )
@@ -316,7 +309,7 @@ def stop_thread(self):
                         self._thread.kill()
                 else:
                     self._thread.kill()
-            while self._is_port_open(self._host, self._port):
+            while _is_port_open(self._host, self._port):
                 time.sleep(0.1)
 
     def stop_proxy(self):

src/taipy/gui/utils/__init__.py

@@ -34,6 +34,7 @@
 from .getdatecolstrname import _RE_PD_TYPE, _get_date_col_str_name
 from .html import _get_css_var_value
 from .is_debugging import is_debugging
+from .is_port_open import _is_port_open
 from .isnotebook import _is_in_notebook
 from .types import (
     _TaipyBase,

src/taipy/gui/utils/is_port_open.py

@@ -0,0 +1,19 @@
+# Copyright 2023 Avaiga Private Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+# an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations under the License.
+
+import socket
+
+
+def _is_port_open(host, port) -> bool:
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    result = sock.connect_ex((host, port))
+    sock.close()
+    return result == 0

src/taipy/gui/utils/proxy.py

@@ -27,6 +27,7 @@
 from twisted.web.resource import Resource
 from twisted.web.server import NOT_DONE_YET, Site
 
+from .is_port_open import _is_port_open
 from .singleton import _Singleton
 
 if t.TYPE_CHECKING:
@@ -93,10 +94,16 @@ def __init__(self, gui: "Gui", listening_port: int) -> None:
     def run(self):
         if self._is_running:
             return
-        self._is_running = True
-        site = Site(_TaipyReverseProxyResource(self._gui._get_config("host", "127.0.0.1"), b"", self._gui))
-        reactor.listenTCP(self._listening_port, site)
+        host = self._gui._get_config("host", "127.0.0.1")
+        port = self._listening_port
+        if _is_port_open(host, port):
+            raise ConnectionError(
+                f"Port {port} is already opened on {host}. You have another server application running on the same port."
+            )
+        site = Site(_TaipyReverseProxyResource(host, b"", self._gui))
+        reactor.listenTCP(port, site)
         Thread(target=reactor.run, args=(False,)).start()
+        self._is_running = True
 
     def stop(self):
         if not self._is_running: