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142 lines
4.5 KiB
Python
Executable file
142 lines
4.5 KiB
Python
Executable file
"Framework for command line interfaces like CVS. See class CmdFrameWork."
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class CommandFrameWork:
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"""Framework class for command line interfaces like CVS.
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The general command line structure is
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command [flags] subcommand [subflags] [argument] ...
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There's a class variable GlobalFlags which specifies the
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global flags options. Subcommands are defined by defining
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methods named do_<subcommand>. Flags for the subcommand are
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defined by defining class or instance variables named
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flags_<subcommand>. If there's no command, method default()
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is called. The __doc__ strings for the do_ methods are used
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for the usage message, printed after the general usage message
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which is the class variable UsageMessage. The class variable
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PostUsageMessage is printed after all the do_ methods' __doc__
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strings. The method's return value can be a suggested exit
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status. [XXX Need to rewrite this to clarify it.]
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Common usage is to derive a class, instantiate it, and then call its
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run() method; by default this takes its arguments from sys.argv[1:].
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"""
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UsageMessage = \
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"usage: (name)s [flags] subcommand [subflags] [argument] ..."
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PostUsageMessage = None
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GlobalFlags = ''
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def __init__(self):
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"""Constructor, present for completeness."""
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pass
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def run(self, args = None):
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"""Process flags, subcommand and options, then run it."""
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import getopt, sys
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if args is None: args = sys.argv[1:]
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try:
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opts, args = getopt.getopt(args, self.GlobalFlags)
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except getopt.error as msg:
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return self.usage(msg)
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self.options(opts)
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if not args:
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self.ready()
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return self.default()
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else:
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cmd = args[0]
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mname = 'do_' + cmd
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fname = 'flags_' + cmd
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try:
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method = getattr(self, mname)
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except AttributeError:
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return self.usage("command %r unknown" % (cmd,))
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try:
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flags = getattr(self, fname)
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except AttributeError:
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flags = ''
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try:
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opts, args = getopt.getopt(args[1:], flags)
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except getopt.error as msg:
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return self.usage(
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"subcommand %s: " % cmd + str(msg))
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self.ready()
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return method(opts, args)
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def options(self, opts):
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"""Process the options retrieved by getopt.
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Override this if you have any options."""
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if opts:
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print("-"*40)
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print("Options:")
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for o, a in opts:
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print('option', o, 'value', repr(a))
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print("-"*40)
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def ready(self):
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"""Called just before calling the subcommand."""
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pass
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def usage(self, msg = None):
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"""Print usage message. Return suitable exit code (2)."""
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if msg: print(msg)
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print(self.UsageMessage % {'name': self.__class__.__name__})
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docstrings = {}
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c = self.__class__
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while 1:
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for name in dir(c):
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if name[:3] == 'do_':
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if name in docstrings:
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continue
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try:
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doc = getattr(c, name).__doc__
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except:
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doc = None
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if doc:
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docstrings[name] = doc
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if not c.__bases__:
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break
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c = c.__bases__[0]
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if docstrings:
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print("where subcommand can be:")
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for name in sorted(docstrings.keys()):
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print(docstrings[name])
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if self.PostUsageMessage:
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print(self.PostUsageMessage)
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return 2
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def default(self):
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"""Default method, called when no subcommand is given.
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You should always override this."""
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print("Nobody expects the Spanish Inquisition!")
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def test():
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"""Test script -- called when this module is run as a script."""
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import sys
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class Hello(CommandFrameWork):
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def do_hello(self, opts, args):
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"hello -- print 'hello world', needs no arguments"
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print("Hello, world")
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x = Hello()
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tests = [
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[],
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['hello'],
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['spam'],
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['-x'],
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['hello', '-x'],
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None,
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]
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for t in tests:
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print('-'*10, t, '-'*10)
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sts = x.run(t)
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print("Exit status:", repr(sts))
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if __name__ == '__main__':
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test()
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