检索 subprocess.call() 的输出

2022-01-18 00:00:00 python subprocess pipe stringio

问题描述

如何获得使用 subprocess.call() 运行的进程的输出?

How can I get the output of a process run using subprocess.call()?

将 StringIO.StringIO 对象传递给 stdout 会出现以下错误:

Passing a StringIO.StringIO object to stdout gives this error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/subprocess.py", line 444, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/subprocess.py", line 588, in __init__
    errread, errwrite) = self._get_handles(stdin, stdout, stderr)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/subprocess.py", line 945, in _get_handles
    c2pwrite = stdout.fileno()
AttributeError: StringIO instance has no attribute 'fileno'
>>>

解决方案

subprocess.call() 的输出只能重定向到文件.

Output from subprocess.call() should only be redirected to files.

您应该改用 subprocess.Popen().然后，您可以为 stderr、stdout 和/或 stdin 参数传递 subprocess.PIPE，并使用 communicate() 方法从管道中读取:

You should use subprocess.Popen() instead. Then you can pass subprocess.PIPE for the stderr, stdout, and/or stdin parameters and read from the pipes by using the communicate() method:

from subprocess import Popen, PIPE

p = Popen(['program', 'arg1'], stdin=PIPE, stdout=PIPE, stderr=PIPE)
output, err = p.communicate(b"input data that is passed to subprocess' stdin")
rc = p.returncode

原因是subprocess.call()使用的类文件对象必须有一个真实的文件描述符，从而实现fileno()方法.仅使用任何类似文件的对象都无法解决问题.

The reasoning is that the file-like object used by subprocess.call() must have a real file descriptor, and thus implement the fileno() method. Just using any file-like object won't do the trick.

请参阅此处了解更多信息.

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