Initial revision

Demo/pdist/cmdfw.py

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