from __future__ import absolute_import
# Copyright (c) 2010-2017 openpyxl
"""
Based on Python Cookbook 3rd Edition, 8.13
http://chimera.labs.oreilly.com/books/1230000000393/ch08.html#_discussion_130
"""
import datetime
import re
from openpyxl.compat import basestring, bytes, long
from openpyxl.utils.datetime import W3CDTF_to_datetime
from .namespace import namespaced
[docs]class Descriptor(object):
def __init__(self, name=None, **kw):
self.name = name
for k, v in kw.items():
setattr(self, k, v)
def __set__(self, instance, value):
instance.__dict__[self.name] = value
[docs]class Typed(Descriptor):
"""Values must of a particular type"""
expected_type = type(None)
allow_none = False
nested = False
def __init__(self, *args, **kw):
super(Typed, self).__init__(*args, **kw)
self.__doc__ = "Values must be of type {0}".format(self.expected_type)
def __set__(self, instance, value):
if not isinstance(value, self.expected_type):
if (not self.allow_none
or (self.allow_none and value is not None)):
raise TypeError('expected ' + str(self.expected_type))
super(Typed, self).__set__(instance, value)
def __repr__(self):
return self.__doc__
def _convert(expected_type, value):
"""
Check value is of or can be converted to expected type.
"""
if not isinstance(value, expected_type):
try:
value = expected_type(value)
except:
raise TypeError('expected ' + str(expected_type))
return value
[docs]class Convertible(Typed):
"""Values must be convertible to a particular type"""
def __set__(self, instance, value):
if ((self.allow_none and value is not None)
or not self.allow_none):
value = _convert(self.expected_type, value)
super(Convertible, self).__set__(instance, value)
[docs]class Max(Convertible):
"""Values must be less than a `max` value"""
expected_type = float
allow_none = False
def __init__(self, **kw):
if 'max' not in kw and not hasattr(self, 'max'):
raise TypeError('missing max value')
super(Max, self).__init__(**kw)
def __set__(self, instance, value):
if ((self.allow_none and value is not None)
or not self.allow_none):
value = _convert(self.expected_type, value)
if value > self.max:
raise ValueError('Max value is {0}'.format(self.max))
super(Max, self).__set__(instance, value)
[docs]class Min(Convertible):
"""Values must be greater than a `min` value"""
expected_type = float
allow_none = False
def __init__(self, **kw):
if 'min' not in kw and not hasattr(self, 'min'):
raise TypeError('missing min value')
super(Min, self).__init__(**kw)
def __set__(self, instance, value):
if ((self.allow_none and value is not None)
or not self.allow_none):
value = _convert(self.expected_type, value)
if value < self.min:
raise ValueError('Min value is {0}'.format(self.min))
super(Min, self).__set__(instance, value)
[docs]class MinMax(Min, Max):
"""Values must be greater than `min` value and less than a `max` one"""
pass
[docs]class Set(Descriptor):
"""Value can only be from a set of know values"""
def __init__(self, name=None, **kw):
if not 'values' in kw:
raise TypeError("missing set of values")
kw['values'] = set(kw['values'])
super(Set, self).__init__(name, **kw)
self.__doc__ = "Value must be one of {0}".format(self.values)
def __set__(self, instance, value):
if value not in self.values:
raise ValueError(self.__doc__)
super(Set, self).__set__(instance, value)
[docs]class NoneSet(Set):
"""'none' will be treated as None"""
def __init__(self, name=None, **kw):
super(NoneSet, self).__init__(name, **kw)
self.values.add(None)
def __set__(self, instance, value):
if value == 'none':
value = None
super(NoneSet, self).__set__(instance, value)
[docs]class Integer(Convertible):
expected_type = long
[docs]class Float(Convertible):
expected_type = float
[docs]class Bool(Convertible):
expected_type = bool
def __set__(self, instance, value):
if isinstance(value, str):
if value in ('false', 'f', '0'):
value = False
super(Bool, self).__set__(instance, value)
[docs]class String(Typed):
expected_type = basestring
[docs]class Text(String, Convertible):
pass
[docs]class ASCII(Typed):
expected_type = bytes
[docs]class Tuple(Typed):
expected_type = tuple
[docs]class Length(Descriptor):
def __init__(self, name=None, **kw):
if "length" not in kw:
raise TypeError("value length must be supplied")
super(Length, self).__init__(**kw)
def __set__(self, instance, value):
if len(value) != self.length:
raise ValueError("Value must be length {0}".format(self.length))
super(Length, self).__set__(instance, value)
[docs]class Default(Typed):
"""
When called returns an instance of the expected type.
Additional default values can be passed in to the descriptor
"""
def __init__(self, name=None, **kw):
if "defaults" not in kw:
kw['defaults'] = {}
super(Default, self).__init__(**kw)
def __call__(self):
return self.expected_type()
[docs]class Alias(Descriptor):
"""
Aliases can be used when either the desired attribute name is not allowed
or confusing in Python (eg. "type") or a more descriptve name is desired
(eg. "underline" for "u")
"""
def __init__(self, alias):
self.alias = alias
def __set__(self, instance, value):
setattr(instance, self.alias, value)
def __get__(self, instance, cls):
return getattr(instance, self.alias)
[docs]class MatchPattern(Descriptor):
"""Values must match a regex pattern """
allow_none = False
def __init__(self, name=None, **kw):
if 'pattern' not in kw and not hasattr(self, 'pattern'):
raise TypeError('missing pattern value')
super(MatchPattern, self).__init__(name, **kw)
self.test_pattern = re.compile(self.pattern, re.VERBOSE)
def __set__(self, instance, value):
if value is None and not self.allow_none:
raise ValueError("Value must not be none")
if ((self.allow_none and value is not None)
or not self.allow_none):
if not self.test_pattern.match(value):
raise ValueError('Value does not match pattern {0}'.format(self.pattern))
super(MatchPattern, self).__set__(instance, value)
[docs]class DateTime(Typed):
expected_type = datetime.datetime
def __set__(self, instance, value):
if value is not None and isinstance(value, basestring):
try:
value = W3CDTF_to_datetime(value)
except ValueError:
raise ValueError("Value must be ISO datetime format")
super(DateTime, self).__set__(instance, value)