Rails 3 - 自定义验证

Question

我对自定义验证选项在Rails 3中的选择有些困惑，我希望有人能指点我可以帮助解决当前问题的资源。

我目前有3个型号，vehicle,trim和model_year。他们看起来如下：

class Vehicle < ActiveRecord::Base 
    attr_accessible :make_id, :model_id, :trim_id, :model_year_id 
    belongs_to :trim 
    belongs_to :model_year 
end
 

class ModelYear < ActiveRecord::Base attr_accessible :value has_many :model_year_trims has_many :trims, :through => :model_year_trims end
 

class Trim < ActiveRecord::Base attr_accessible :value, :model_id has_many :vehicles has_many :model_year_trims has_many :model_years, :through => :model_year_trims end 

我的查询是这样的 - 当我创建车辆时，如何确保所选的model_year对修剪有效（反之亦然）？

Answer 1

您可以使用自定义的验证方法，如描述here：

class Vehicle < ActiveRecord::Base 
    validate :model_year_valid_for_trim 

    def model_year_valid_for_trim 
    if #some validation code for model year and trim 
     errors.add(:model_years, "some error") 
    end 
    end 

end 

Answer 2

可以使用ActiveModel::Validator类，像这样：

class VehicleValidator < ActiveModel::Validator 
    def validate(record) 
    return true if # custom model_year and trip logic 
    record.errors[:base] << # error message 
    end 
end 

class Vehicle < ActiveRecord::Base 
    attr_accessible :make_id, :model_id, :trim_id, :model_year_id 
    belongs_to :trim 
    belongs_to :model_year 

    include ActiveModel::Validations 
    validates_with VehicleValidator 
end