The example code pyserial doesn't work on windows,

[v479038280]

Description

pyserial works fine without nicegui,but when running the example on windows,this error occurred ,

"D:\Program Files\python\Lib\site-packages\serial\serialwin32.py", line 64, in open
    raise SerialException("could not open port {!r}: {!r}".format(self.portstr, ctypes.WinError()))
serial.serialutil.SerialException: could not open port 'COM1': PermissionError(13, 'Refused', None, 5)

It seems than we must open the port first

[v479038280]

got more error when running on another windows system

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "multiprocessing\spawn.py", line 122, in spawn_main
  File "multiprocessing\spawn.py", line 131, in _main
  File "multiprocessing\spawn.py", line 246, in prepare
  File "multiprocessing\spawn.py", line 297, in _fixup_main_from_path
  File "<frozen runpy>", line 291, in run_path
  File "<frozen runpy>", line 98, in _run_module_code
  File "<frozen runpy>", line 88, in _run_code
  File "D:\temp\dist_app\app100\serial_data_handle.py", line 9, in <module>
    ser = serial.Serial('COM1',115200,timeout=5)  
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\temp\dist_app\sys_pack\Lib\site-packages\serial\serialwin32.py", line 33, in __init__
    super(Serial, self).__init__(*args, **kwargs)
  File "D:\temp\dist_app\sys_pack\Lib\site-packages\serial\serialutil.py", line 244, in __init__
    self.open()
  File "D:\temp\dist_app\sys_pack\Lib\site-packages\serial\serialwin32.py", line 64, in open
    raise SerialException("could not open port {!r}: {!r}".format(self.portstr, ctypes.WinError()))
serial.serialutil.SerialException: could not open port 'COM1': PermissionError(13, 'Refused。', None, 5)

[v479038280]

This one works fine ,

import serial

from nicegui import app, run, ui

ui.input('Send command').on('keydown.enter', lambda e: (
    ser.write(f'{e.sender.value}\n'.encode()),
    e.sender.set_value(''),
))
log = ui.log()


async def read_loop() -> None:
    global ser
    ser = serial.Serial('COM1',115200,timeout=5)
    while not app.is_stopped and ser.is_open:
        line = await run.io_bound(ser.readline)
        if line:
            log.push(line.decode())
    ser.close()

app.on_startup(read_loop)
ui.run()

[v479038280]

run.io_bond() is too slow. serial_asyncio is much better .