src/mailman/utilities/interact.py

   1 # Copyright (C) 2006-2016 by the Free Software Foundation, Inc.
   2 #
   3 # This file is part of GNU Mailman.
   4 #
   5 # GNU Mailman is free software: you can redistribute it and/or modify it under
   6 # the terms of the GNU General Public License as published by the Free
   7 # Software Foundation, either version 3 of the License, or (at your option)
   8 # any later version.
   9 #
  10 # GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
  11 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13 # more details.
  14 #
  15 # You should have received a copy of the GNU General Public License along with
  16 # GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 """Provide an interactive prompt, mimicking the Python interpreter."""
  19
  20 import os
  21 import sys
  22 import code
  23
  24 from mailman import public
  25
  26
  27 DEFAULT_BANNER = object()
  28
  29
  30 @public
  31 def interact(upframe=True, banner=DEFAULT_BANNER, overrides=None):
  32     """Start an interactive interpreter prompt.
  33
  34     :param upframe: Whether or not to populate the interpreter's globals with
  35         the locals from the frame that called this function.
  36     :type upframe: bool
  37     :param banner: The banner to print before the interpreter starts.
  38     :type banner: string
  39     :param overrides: Additional interpreter globals to add.
  40     :type overrides: dict
  41     """
  42     # The interactive prompt's namespace.
  43     namespace = dict()
  44     # Populate the console's with the locals of the frame that called this
  45     # function (i.e. one up from here).
  46     if upframe:
  47         frame = sys._getframe(1)
  48         namespace.update(frame.f_globals)
  49         namespace.update(frame.f_locals)
  50     if overrides is not None:
  51         namespace.update(overrides)
  52     interp = code.InteractiveConsole(namespace)
  53     # Try to import the readline module, but don't worry if it's unavailable.
  54     try:
  55         import readline                             # noqa
  56     except ImportError:                             # pragma: no cover
  57         pass
  58     # Mimic the real interactive interpreter's loading of any $PYTHONSTARTUP
  59     # file.  Note that if the startup file is not prepared to be exec'd more
  60     # than once, this could cause a problem.
  61     startup = os.environ.get('PYTHONSTARTUP')
  62     if startup:
  63         with open(startup, 'r', encoding='utf-8') as fp:
  64             interp.runcode(compile(fp.read(), startup, 'exec'))
  65     # We don't want the funky console object in parentheses in the banner.
  66     if banner is DEFAULT_BANNER:
  67         banner = '''\
  68 Python %s on %s
  69 Type "help", "copyright", "credits" or "license" for more information.''' % (
  70             sys.version, sys.platform)
  71     interp.interact(banner)