I want to call up an editor in a python script to solicit input from the user, much like
crontab e or
git commit does.
Here’s a snippet from what I have running so far. (In the future, I might use $EDITOR instead of vim so that folks can customize to their liking.)
tmp_file = '/tmp/up.'+''.join(random.choice(string.ascii_uppercase + string.digits) for x in range(6)) edit_call = [ "vim",tmp_file] edit = subprocess.Popen(edit_call,stdin=subprocess.PIPE, stdout=subprocess.PIPE, shell=True )
My problem is that by using Popen, it seems to keep my i/o with the python script from going into the running copy of vim, and I can’t find a way to just pass the i/o through to vim. I get the following error.
Vim: Warning: Output is not to a terminal Vim: Warning: Input is not from a terminal
What’s the best way to call a CLI program from python, hand control over to it, and then pass it back once you’re finished with it?
Calling up $EDITOR is easy. I’ve written this kind of code to call up editor:
import sys, tempfile, os from subprocess import call EDITOR = os.environ.get('EDITOR','vim') #that easy! initial_message = "" # if you want to set up the file somehow with tempfile.NamedTemporaryFile(suffix=".tmp") as tf: tf.write(initial_message) tf.flush() call([EDITOR, tf.name]) # do the parsing with `tf` using regular File operations. # for instance: tf.seek(0) edited_message = tf.read()
The good thing here is, the libraries handle creating and removing the temporary file.
'str' does not support the buffer interface
$ python3 editor.py Traceback (most recent call last): File "editor.py", line 9, in <module> tf.write(initial_message) File "/usr/lib/python3.4/tempfile.py", line 399, in func_wrapper return func(*args, **kwargs) TypeError: 'str' does not support the buffer interface
For python3, use
initial_message = b"" to declare the buffered string.
edited_message.decode("utf-8") to decode the buffer into a string.
import sys, tempfile, os from subprocess import call EDITOR = os.environ.get('EDITOR','vim') #that easy! initial_message = b"" # if you want to set up the file somehow with tempfile.NamedTemporaryFile(suffix=".tmp") as tf: tf.write(initial_message) tf.flush() call([EDITOR, tf.name]) # do the parsing with `tf` using regular File operations. # for instance: tf.seek(0) edited_message = tf.read() print (edited_message.decode("utf-8"))
$ python3 editor.py look a string
$ pip install python-editor $ python import editor result = editor.edit(contents="text to put in editorn")
More details here: https://github.com/fmoo/python-editor
The PIPE is the problem. VIM is an application that depends on the fact that the stdin/stdout channels are terminals and not files or pipes. Removing the stdin/stdout paramters worked for me.
I would avoid using os.system as it should be replaced by the subprocess module.
click is a great library for command line processing and it has some utilities, click.edit() is portable and uses the EDITOR environment variable. I typed the line,
stuff, into the editor. Notice it is returned as a string. Nice.
(venv) /tmp/editor $ export EDITOR='=mvim -f' (venv) /tmp/editor $ python import click click.edit() 'stuffn'
Check out the docs https://click.palletsprojects.com/en/7.x/utils/#launching-editors My entire experience:
/tmp $ mkdir editor /tmp $ cd editor /tmp/editor $ python3 -m venv venv /tmp/editor $ source venv/bin/activate (venv) /tmp/editor $ pip install click Collecting click Using cached https://files.pythonhosted.org/packages/fa/37/45185cb5abbc30d7257104c434fe0b07e5a195a6847506c074527aa599ec/Click-7.0-py2.py3-none-any.whl Installing collected packages: click Successfully installed click-7.0 You are using pip version 19.0.3, however version 19.3.1 is available. You should consider upgrading via the 'pip install --upgrade pip' command. (venv) /tmp/editor $ export EDITOR='=mvim -f' (venv) /tmp/editor $ python Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 16:52:21) [Clang 6.0 (clang-600.0.57)] on darwin Type "help", "copyright", "credits" or "license" for more information. import click click.edit() 'stuffn' >>>