python validation

在Ruby on Rails中，Active Validation是模型层中处理“数据校验”的核心机制。它提供了统一的校验逻辑。但是在Python中缺没有类似的工具。所以，模仿了 Active Validation，写了Python版本的。

#coding: utf-8
import re

class NoOptionError(Exception):
    def __init__(self, options = []):
        self.msg = 'should be in [%s], but noting' % ', '.join(options)


class OptionNameError(Exception):
    def __init__(self, option, options = []):
        should_be = ', '.join(options)
        self.msg = 'should be in [%s], but %s' % (should_be, option)


class Validator(object):

    def _validate_options(self, **options):
        all_null = True
        for opt in options:
            if opt not in self._options:
                raise OptionNameError(opt, self._options)
            else:
                if options[opt] is not None:
                    all_null = False
        if all_null:
            raise NoOptionError(self._options)
        return True


class PresenceValidator(Validator):

    def validate(self, value, allow_blank = True):
        if value is None:
            return False

        if allow_blank:
            if isinstance(value, str): # 字符串要单独处理
                if not value.strip():
                    return True
            if not value:
                return True
        else:
            if isinstance(value, str): # 字符串要单独处理
                if not value.strip():
                    return False
            if (isinstance(value, str) or isinstance(value, list) 
                or isinstance(value, dict) or isinstance(value, tuple)) and not value: # 数字0不用做这个判断
                return False

        return True


class InclusionValidator(Validator):

    def validate(self, value, in_values = [], allow_null = False, allow_blank = False):
        if value is None:
            return allow_null

        if isinstance(value, str):
            value = value.strip()

        if isinstance(value, str) and not value:
            return allow_blank
        return value in in_values


class NumericalityValidator(Validator):
    _options = set([
        'greater_than', 'greater_than_or_equal_to', 'equal_to', 
        'less_than', 'less_than_or_equal_to', 'odd', 'even'
    ])

    def validate(self, value, **options):
        self._validate_options(**options)
        if value is None:
            raise Exception('value can not be null.')
        if type(value) not in (int, long, float):
            raise Exception('value should be a number, but a %s' % type(value))
        if options.get('greater_than', False) and value <= options['greater_than']: 
            return False
        if options.get('greater_than_or_equal_to', False) and value < options['greater_than_or_equal_to']:
            return False
        if options.get('equal_to', False) and value != options['equal_to']:
            return False
        if options.get('less_than', False) and value >= options['less_than']:
            return False
        if options.get('less_than_or_equal_to', False) and value > options['less_than_or_equal_to']:
            return False
        odd = options.get('odd', None)
        if odd in (True, False):
            if odd:
                if value % 2 == 0: return False
            else:
                if value % 2 != 0: return False
        even = options.get('even', None)
        if even in (True, False):
            if even:
                if value % 2 != 0: return False
            else:
                if value % 2 == 0: return False
        return True


class AcceptanceValidator(Validator):

    def validate(self, value, allow_null = True ):
        if allow_null:
            return True
        return value is not None


class LengthValidator(Validator):
    _options = set([
        '_is', 'minimum', 'maximum', 
        'allow_null', 'allow_blank'
    ])

    def validate(self, value, **options):
        self._validate_options(**options)
        if value is None:
            return options.get('allow_null', True)

        if options.get('allow_blank', True):
            if isinstance(value, str):
                if value.strip() == '':
                    return True
            if not value:
                return True
        else:
            if isinstance(value, str):
                if value.strip() == '':
                    return False
            if (isinstance(value, str) or isinstance(value, list) 
                or isinstance(value, dict) or isinstance(value, tuple)) and not value: # 数字0不用做这个判断
                return False

        if options.get('_is', False) and len(value) != options['_is']: 
            return False
        if options.get('minimum', False) and len(value) < options['minimum']:
            return False
        if options.get('maximum', False) and len(value) > options['maximum']:
            return False
        return True


class ConfirmationValidator(Validator):

    def validate(self, value, confirmation_value):
        return confirmation_value == value


class FormatValidator(Validator):

    def validate(self, value, _with = None, allow_null = True, allow_blank = True):
        if value is None:
            return allow_null

        if allow_blank:
            if isinstance(value, str):
                if not value.strip():
                    return True
            if (isinstance(value, str) or isinstance(value, list) 
                or isinstance(value, dict) or isinstance(value, tuple)) and not value: # 数字0不用做这个判断
                return True

        return True if re.match(_with, value) else False


class ExclusionValidator(Validator):

    def validate(self, value, exclusion_values = [], allow_null = False, allow_blank = False):
        if value is None:
            return allow_null

        if isinstance(value, str):
            value = value.strip()

        if (isinstance(value, str) or isinstance(value, list) 
                or isinstance(value, dict) or isinstance(value, tuple)) and not value: # 数字0不用做这个判断
            return allow_blank

        return value not in exclusion_values