Windows下Python subprocess获取netsh输出的编码错误问题

问题描述 #

执行Windows命令netsh wlan show interfaces获取无线网卡信息时，使用utf-8编码解码subprocess输出触发UnicodeDecodeError，相关代码及报错信息如下：

原代码 #

import subprocess

class LocalNetwork:
    def networkinformations():
        result = subprocess.check_output('netsh wlan show interfaces',shell=True,encoding='utf-8').strip().splitlines()
        print(result)

LocalNetwork.networkinformations()

报错回溯 #

Traceback (most recent call last):
  File "d:\Python\Bibliotheken\NetyPy.py", line 8, in <module>
    LocalNetwork.networkinformations()
  File "d:\Python\Bibliotheken\NetyPy.py", line 5, in networkinformations
    result = sub.check_output('netsh wlan show interfaces', shell=True, encoding='utf-8').strip().splitlines()
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.2288.0_x64__qbz5n2kfra8p0\Lib\subprocess.py", line 466, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.2288.0_x64__qbz5n2kfra8p0\Lib\subprocess.py", line 550, in run
    stdout, stderr = process.communicate(input, timeout=timeout)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.2288.0_x64__qbz5n2kfra8p0\Lib\subprocess.py", line 1196, in communicate
    stdout = self.stdout.read()
             ^^^^^^^^^^^^^^^^^^
  File "<frozen codecs>", line 322, in decode
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x84 in position 285: invalid start byte

解决方案 #

Windows终端默认编码并非utf-8，通常为GBK或cp1252（依系统语言而定），以下是几种可行的解决方式：

• 直接指定Windows兼容编码
  将encoding参数改为gbk或cp1252，适配终端输出编码：

  import subprocess
  
  class LocalNetwork:
      def networkinformations():
          result = subprocess.check_output('netsh wlan show interfaces', shell=True, encoding='gbk').strip().splitlines()
          print(result)
  
  LocalNetwork.networkinformations()
  

• 先获取字节流再解码
  先获取原始字节数据，再用正确编码解码，避免编码参数冲突：

  import subprocess
  
  class LocalNetwork:
      def networkinformations():
          byte_result = subprocess.check_output('netsh wlan show interfaces', shell=True)
          result = byte_result.decode('gbk').strip().splitlines()
          print(result)
  
  LocalNetwork.networkinformations()
  

• 自动适配系统编码
  通过locale模块获取系统默认编码，动态设置解码方式：

  import subprocess
  import locale
  
  class LocalNetwork:
      def networkinformations():
          system_encoding = locale.getpreferredencoding()
          result = subprocess.check_output('netsh wlan show interfaces', shell=True, encoding=system_encoding).strip().splitlines()
          print(result)
  
  LocalNetwork.networkinformations()
  

内容的提问来源于stack exchange，提问作者Wolf Eberhardt