1

I have a MOTD-type message which prints on invocation of the interpreter. Currently this is printed up in sitecustomize. I'd like to suppress the message if the interpreter is not in interactive mode; unfortunately all of the checks in Tell if Python is in interactive mode do not work in sitecustomize. (sys.argv, sys.ps1, __main__.__file__ are not populated.) Are there checks which work in sitecustomize?

Community
  • 1
  • 1
jtniehof
  • 581
  • 3
  • 8

3 Answers3

2

JAB got me looking at the code and I ultimately came up with this:

import ctypes
import getopt

ctypes.pythonapi.Py_GetArgcArgv.restype = None
ctypes.pythonapi.Py_GetArgcArgv.argtypes = [
    ctypes.POINTER(ctypes.c_int),
    ctypes.POINTER(ctypes.POINTER(ctypes.c_char_p))]
count = ctypes.c_int()
args = ctypes.pointer(ctypes.c_char_p())
ctypes.pythonapi.Py_GetArgcArgv(ctypes.byref(count), ctypes.byref(args))
argc = count.value
argv = [args[i] for i in range(count.value)]
if argc > 1:
    interactive = False
    opts, args = getopt.getopt(argv[1:], 'i')
    for o, a in opts:
        if o == '-i':
            interactive = True
else:
    interactive = True

Kinda ugly (and for Py3k the c_char_p need to be c_wchar_p) but does the job.

jtniehof
  • 581
  • 3
  • 8
2

Checking the sys.flags is a cleaner way.

>>> import sys  
>>> sys.flags.interactive  
1

Note, the IDLE is also interactive in its nature, but the flag is not set. I would do below: 

>>> if sys.flags.interactive or sys.modules.has_key('idlelib'):  
>>>     pass # do stuff specific to interactive.
Martijn Pieters
  • 1,048,767
  • 296
  • 4,058
  • 3,343
dmu
  • 21
  • 2
  • This only checks if -i was specified on the command line...it fails if the interpreter was started "bare," which still puts it in interactive mode. – jtniehof Aug 29 '11 at 20:30
1

Perhaps this idea for checking interpreter interactivity that utilizes the inspect module and checks stack frames might be of some use to you:

http://mail.python.org/pipermail/pythonmac-sig/2002-February/005054.html

You could also try looking directly at the source of pydoc.help(), which the above-linked code snippets were inspired by.

Just realized that you could simply utilize a file containing your interactive prompt with the PYTHONSTARTUP environment variable. The commands in the file pointed to by PYTHONSTARTUP will only be executed when the interpreter is run interactively.

http://docs.python.org/tutorial/interpreter.html#the-interactive-startup-file

If you don't want to set the environment variable outside of Python, you might be able to set the variable to the desired file in sitecustomize.py, but when I tried looking into it to find the loading order it took me right back to the link from the first part of my answer.

JAB
  • 20,783
  • 6
  • 71
  • 80
  • That code is no longer in pydoc (check the date...) and the stack frame in sitecustomize has no difference between interactive and noninteractive modes. Was worth a check, though. – jtniehof Jul 07 '11 at 17:06
  • Suddenly realized that, for your situation, there's a surprisingly simple solution. See my answer again. – JAB Jul 07 '11 at 17:40
  • I couldn't think of a good way to handle that without stepping on the user's PYTHONSTARTUP, but it got me looking at that code...see my answer. – jtniehof Jul 13 '11 at 17:41