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?
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3 Answers
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.
1 Comment
JAB
Glad you were able to find a solution that works the way you want.
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.
1 Comment
jtniehof
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.
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.
3 Comments
jtniehof
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.
JAB
Suddenly realized that, for your situation, there's a surprisingly simple solution. See my answer again.
jtniehof
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.