Rails 3 - 自定義驗證

Question

我對自定義驗證選項在Rails 3中的選擇有些困惑，我希望有人能指點我可以幫助解決當前問題的資源。

我目前有3個型號，vehicle,trim和model_year。他們看起來如下：

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 

我的查詢是這樣的 - 當我創建車輛時，如何確保所選的model_year對修剪有效（反之亦然）？

Answer 1

您可以使用自定義的驗證方法，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類，像這樣：

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