unchained.py

from django.core.management import BaseCommand, LaxOptionParser, CommandError, ManagementUtility
from django.core.management.base import handle_default_options
from optparse import make_option, OptionParser
import sys

class SubManagementUtil(ManagementUtility):
    
    def __init__(self, argv=None, commands={}):
        self.commands = commands
        super(SubManagementUtil, self).__init__(argv)
    
    def main_help_text(self, commands_only=False):
        if commands_only:
            usage = sorted(self.commands.keys())
        else:
            usage = [
                "",
                "Type '%s help <subcommand>' for help on a specific subcommand." % self.prog_name,
                "",
                "Available subcommands:",
            ]
            for cmdname in self.commands.keys():
                usage.append("    %s" % cmdname)
        
        return '\n'.join(usage)
    
    def fetch_command(self, subcommand):
        try:
            cls = self.commands[subcommand]
            return cls()
        except KeyError:
            sys.stderr.write("Unknown command: %r\nType '%s help' for usage.\n" % \
            (subcommand, self.prog_name))
            sys.exit(1)



class SubCommand(BaseCommand):
    
    args = "<subcommand>"
    help = "Execute the specified subcommand"
    
    subcommands = {}
    
    def create_parser(self, prog_name, subcommand):
        return LaxOptionParser(prog=prog_name,
                                 usage=self.usage(subcommand),
                                 version=self.get_version(),
                                 option_list=self.option_list)
    
    def print_help(self, prog_name, subcommand):
        parser = self.create_parser(prog_name, subcommand)
        parser.print_lax_help()
    
    
    def get_subcommand(self, name):
        if not name in self.subcommands:
            raise CommandError('Unknown subcommand %s' % name)
        else:
            return self.subcommands[name]()
    
    
    def run_from_argv(self, argv):
        utility = SubManagementUtil(argv[1:], self.subcommands)
        utility.execute()