What interface is a ‘Popen.stdout’ presenting?

Wed Dec 23 20:24:17 EST 2015

Howdy all,
When I want to wrap a binary stream to provide a text stream, such as
the ‘Popen.stdout’ attribute from a subprocess, I can use
‘io.TextIOWrapper’.
That works on Python 3::
 $ python3
 Python 3.4.4rc1 (default, Dec 7 2015, 11:09:54)
 [GCC 5.3.1 20151205] on linux
 Type "help", "copyright", "credits" or "license" for more information.
 >>> import subprocess
 >>> import io
 >>> gnupg_subprocess = subprocess.Popen(["/usr/bin/gpg", "--version"], stdout=subprocess.PIPE)
 >>> gnupg_stdout = io.TextIOWrapper(gnupg_subprocess.stdout)
 >>> type(gnupg_stdout)
 <class '_io.TextIOWrapper'>
but not Python 2::
 $ python2
 Python 2.7.11 (default, Dec 9 2015, 00:29:25)
 [GCC 5.3.1 20151205] on linux2
 Type "help", "copyright", "credits" or "license" for more information.
 >>> import subprocess
 >>> import io
 >>> gnupg_subprocess = subprocess.Popen(["/usr/bin/gpg", "--version"], stdout=subprocess.PIPE)
 >>> gnupg_stdout = io.TextIOWrapper(gnupg_subprocess.stdout)
 Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 AttributeError: 'file' object has no attribute 'readable'
I'm trying to write code that, as far as practicable, works unchanged on
Python 2 and Python 3.
How do I wrap an arbitrary byte stream – already opened, such as a
‘Popen.stdout’ attribute – in a text wrapper with a particular encoding?
-- 
 \ “With Lisp or Forth, a master programmer has unlimited power |
 `\ and expressiveness. With Python, even a regular guy can reach |
_o__) for the stars.” —Raymond Hettinger |
Ben Finney