create & read from tempfile

Question

Is there anyway I could write to tempfile and include it in a command, and then close/remove it. I would like to execute the command, eg: some_command /tmp/some-temp-file.

Answer 1

Try this:

import tempfile
import commands
import os

commandname = "cat"

f = tempfile.NamedTemporaryFile(delete=False)
f.write("oh hello there")
f.close() # file is not immediately deleted because we
          # used delete=False

res = commands.getoutput("%s %s" % (commandname,f.name))
print res
os.unlink(f.name)

It just prints the content of the temp file, but that should give you the right idea. Note that the file is closed (f.close()) before the external process gets to see it. That's important -- it ensures that all your write ops are properly flushed (and, in Windows, that you're not locking the file). NamedTemporaryFile instances are usually deleted as soon as they are closed; hence the delete=False bit.

If you want more control over the process, you could try subprocess.Popen, but it sounds like commands.getoutput may be sufficient for your purposes.