[Python] - Getting data from external program

Question

Hey,

I need a method to get the data from an external editor.

def _get_content():
     from subprocess import call
     file = open(file, "w").write(some_name)
     call(editor + " " + file, shell=True)
     file.close()
     file = open(file)
     x = file.readlines()

     [snip]

I personally think there should be a more elegant way. You see, I need to interact with an external editor and get the data.

Do you know any better approaches/have better ideas?

EDIT:

Marcelo brought me on the idea of using tempfile for doing that.

Here's how I do it:

def _tempfile_write(input):
    from tempfile import NamedTemporaryFile

    x = NamedTemporaryFile()
    x.file.write(input)
    x.close()
    y = open(x)

    [snip]

This does the job, but also not quite satisfying. Heard something about spawning?..

Answer 1

This is the way all programs do it, AFAIK. Certainly all version control systems that I've used create a temporary file, pass it to the editor and retrieve the result when the editor exits, just as you have.

Answer 2

an editor just lets you edit a file interactively. you can also edit files with Python. there's no need to call external editor.

for line in open("file"):
    print "editing line ", line
    # eg replace strings
    line = line.replace("somestring","somenewstring")
    print line

Answer 3

I'd recommend using a list, not a string:

def _get_content(editor, initial=""):
    from subprocess import call
    from tempfile import NamedTemporaryFile

    # Create the initial temporary file.
    with NamedTemporaryFile(delete=False) as tf:
        tfName = tf.name
        tf.write(initial)

    # Fire up the editor.
    if call([editor, tfName]) != 0:
        return None # Editor died or was killed.

    # Get the modified content.
    with open(tfName).readlines() as result:
        os.remove(tfName)
        return result