使用pyFirmata报错：AttributeError: module 'inspect' has no attribute 'getargspec'

问题详情 #

运行最基础的pyFirmata代码也无法正常初始化Arduino，代码如下：

from pyfirmata import Arduino,util
import time

port = 'COM5'
board = Arduino(port)

执行后抛出错误：

Traceback (most recent call last):
  File "c:\Users\Public\pythonpublic\arduino.py", line 5, in <module>
    board = Arduino(port)
            ^^^^^^^^^^^^^
  File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\__init__.py", line 19, in __init__      
    super(Arduino, self).__init__(*args, **kwargs)
  File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py", line 101, in __init__    
    self.setup_layout(layout)
  File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py", line 157, in setup_layout
    self._set_default_handlers()
  File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py", line 161, in _set_default_handlers
    self.add_cmd_handler(ANALOG_MESSAGE, self._handle_analog_message)
  File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py", line 185, in add_cmd_handler
    len_args = len(inspect.getargspec(func)[0])
                   ^^^^^^^^^^^^^^^^^^
AttributeError: module 'inspect' has no attribute 'getargspec'. Did you mean: 'getargs'?

问题原因 #

Python 3.10及以上版本已移除inspect.getargspec()方法（该方法在Python 3.0就被标记为弃用），而当前使用的pyFirmata版本仍在调用这个已淘汰的API，导致报错。

解决方案 #

方案1：升级到维护版pyfirmata2 #

原版pyFirmata已长时间未更新，推荐使用兼容Python 3.10+的维护分支pyfirmata2：

1. 安装pyfirmata2：

pip install --upgrade pyfirmata2

2. 修改代码中的导入语句：

from pyfirmata2 import Arduino, util
import time

port = 'COM5'
board = Arduino(port)

方案2：手动修改pyFirmata源码 #

如果不想更换库，可直接修改报错的源码：

1. 找到报错的pyfirmata.py文件（路径见报错信息：C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py）
2. 定位到add_cmd_handler方法中的这一行：

len_args = len(inspect.getargspec(func)[0])

3. 将其替换为：

len_args = len(list(inspect.signature(func).parameters.keys()))

4. 保存文件后重新运行代码即可。

内容的提问来源于stack exchange，提问作者clueless