base.py 文件源码

def execute(self, *args, **options):
        """
        Try to execute this command, performing system checks if needed (as
        controlled by attributes ``self.requires_system_checks`` and
        ``self.requires_model_validation``, except if force-skipped).
        """
        if options.get('no_color'):
            self.style = no_style()
            self.stderr.style_func = None
        if options.get('stdout'):
            self.stdout = OutputWrapper(options['stdout'])
        if options.get('stderr'):
            self.stderr = OutputWrapper(options.get('stderr'), self.stderr.style_func)

        saved_locale = None
        if not self.leave_locale_alone:
            # Only mess with locales if we can assume we have a working
            # settings file, because django.utils.translation requires settings
            # (The final saying about whether the i18n machinery is active will be
            # found in the value of the USE_I18N setting)
            if not self.can_import_settings:
                raise CommandError("Incompatible values of 'leave_locale_alone' "
                                   "(%s) and 'can_import_settings' (%s) command "
                                   "options." % (self.leave_locale_alone,
                                                 self.can_import_settings))
            # Deactivate translations, because django-admin creates database
            # content like permissions, and those shouldn't contain any
            # translations.
            from django.utils import translation
            saved_locale = translation.get_language()
            translation.deactivate_all()

        try:
            if (self.requires_system_checks and
                    not options.get('skip_validation') and  # Remove at the end of deprecation for `skip_validation`.
                    not options.get('skip_checks')):
                self.check()
            output = self.handle(*args, **options)
            if output:
                if self.output_transaction:
                    # This needs to be imported here, because it relies on
                    # settings.
                    from django.db import connections, DEFAULT_DB_ALIAS
                    connection = connections[options.get('database', DEFAULT_DB_ALIAS)]
                    if connection.ops.start_transaction_sql():
                        self.stdout.write(self.style.SQL_KEYWORD(connection.ops.start_transaction_sql()))
                self.stdout.write(output)
                if self.output_transaction:
                    self.stdout.write('\n' + self.style.SQL_KEYWORD(connection.ops.end_transaction_sql()))
        finally:
            if saved_locale is not None:
                translation.activate(saved_locale)