rrule converter

gistfile1.py

from dateutil import parser, rrule

class BaseArgConverter(object):

    def convert_value(self, value):
        """convert either a single value or sequence"""
        sequence = value.split(',')
        if len(sequence) > 1:
            return map(self._convert_value, sequence)
        return self._convert_value(value)

class ConstantArgConverter(BaseArgConverter):
    kwargs = {'freq', 'wkst'}

    def _convert_value(self, value):
        return getattr(rrule, value.upper())

class BooleanArgConverter(BaseArgConverter):
    kwargs = {'cache'}

    def _convert_value(self, value):
        return bool(value)

class DateTimeArgConverter(BaseArgConverter):
    kwargs = {'dtstart', 'until'}

    def _convert_value(self, value):
        return parser.parse(value)

class IntegerArgConverter(BaseArgConverter):
    kwargs = {'bysetpos', 'bymonth', 'bymonthday', 'byyearday',
        'byweekno','byweekday', 'byhour', 'byminute', 'bysecond', 'byeaster',
        'count', 'interval'
    }

    def _convert_value(self, value):
        return int(value)

class ArgConverter(object):
    registry = {
        ConstantArgConverter, BooleanArgConverter,
        DateTimeArgConverter, IntegerArgConverter,
    }

    def __init__(self):
        self.arg_to_converter = dict()
        for converter_class in self.registry:
            converter = converter_class()
            for kwarg in converter.kwargs:
                self.arg_to_converter[kwarg.lower()] = converter

    def convert(self, kwarg, value):
        converter = self.arg_to_converter[kwarg.lower()]
        return converter.convert_value(value)

class RruleConverter(object):
    arg_converter = ArgConverter()

    def _convert(self, raw_rrule):
        args_raw = raw_rrule.split(';')

        rrule_kwargs = dict()
        for arg_raw in args_raw:
            kwarg, value = arg_raw.split('=')
            type_safe_value = self.arg_converter.convert(kwarg, value)
            rrule_kwargs[kwarg.lower()] = type_safe_value

        return rrule.rrule(**rrule_kwargs)

    def convert(self, raw_rrules):
        if isinstance(raw_rrules, (list, tuple)) and len(raw_rrules) > 1:
            return map(self._convert, raw_rrules)
        return self._convert(raw_rrules)

if __name__ == '__main__':
    rrule_converter = RruleConverter()
    rrule_raw = ['FREQ=DAILY;BYHOUR=10;BYMINUTE=00;UNTIL=20070527T235959', 'FREQ=DAILY;BYHOUR=17;BYMINUTE=00;UNTIL=20070527T235959', 'FREQ=DAILY;INTERVAL=1']
    print rrule_converter.convert(rrule_raw)