我有几个带有日期属性的模型,对于每个模型,我想根据给定的范围验证这些日期.一个基本的例子是：
validates_inclusion_of :dated_on,:in => Date.new(2000,1,1)..Date(2020,1)
理想情况下,我想使用与named_scope使用类似的方法在运行时评估日期范围,例如：
validates_inclusion_of :dated_on,:in => lambda {{ (Date.today - 2.years)..(Date.today + 2.years)}}
解决方法
如果每个类的验证相同,答案很简单：将验证方法放入模块并将其混合到每个模型中,然后使用validate添加验证：
# in lib/validates_dated_on_around_now
module ValidatesDatedOnAroundNow
protected
def validate_dated_around_now
# make sure dated_on isn't more than five years in the past or future
self.errors.add(:dated_on,"is not valid") unless ((5.years.ago)..(5.years.from_now)).include?(self.dated_on)
end
end
class FirstModel
include ValidatesDatedOnAroundNow
validate :validate_dated_around_now
end
class SecondModel
include ValidatesDatedOnAroundNow
validate :validate_dated_around_now
end
如果你想为每个模型设置不同的范围,你可能想要更像这样的东西：
module ValidatesDateOnWithin
def validates_dated_on_within(&range_lambda)
validates_each :dated_on do |record,attr,value|
range = range_lambda.call
record.errors.add(attr_name,:inclusion,:value => value) unless range.include?(value)
end
end
end
class FirstModel
extend ValidatesDatedOnWithin
validates_dated_on_within { ((5.years.ago)..(5.years.from_now)) }
end
class SecondModel
extend ValidatesDatedOnWithin
validates_dated_on_within { ((2.years.ago)..(2.years.from_now)) }
end