Question

I want to replicate the functionality that happens when you do something like ‘git commit’. It opens up your editor and you type some stuff and then save/exit to hand off that file back to the script that launched the editor.

How would I implement this functionality in Python?

EDIT:

Thanks for the suggestions, here’s a working example based on the answers:

import os, subprocess, tempfile

(fd, path) = tempfile.mkstemp()
fp = os.fdopen(fd, 'w')
fp.write('default')
fp.close()

editor = os.getenv('EDITOR', 'vi')
print(editor, path)
subprocess.call('%s %s' % (editor, path), shell=True)

with open(path, 'r') as f:
  print(f.read())

os.unlink(path)

Answer 1

The usual case is to:

1. Create a temporary file, write default contents to it
2. Launch the command stored in the environment variable “EDITOR”. This usually is a shell command, so it might contain arguments -> run it thourgh the shell or parse it accordingly
3. Once the process terminates, read back temporary file
4. Remove temporary file

So something like this:

import os, subprocess, tempfile
f, fname = tempfile.mkstemp()
f.write('default')
f.close()
cmd = os.environ.get('EDITOR', 'vi') + ' ' + fname
subprocess.call(cmd, shell=True)
with open(fname, 'r') as f:
    #read file
os.unlink(fname)