call up an EDITOR (vim) from a python script

Question

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?

Answer 1

In python3: '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.

Then use 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"))

Result:

$ python3 editor.py
look a string

Answer 2

Package python-editor:

$ pip install python-editor
$ python
>>> import editor
>>> result = editor.edit(contents="text to put in editor\n")

More details here: https://github.com/fmoo/python-editor

Answer 3

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.

Answer 4

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.