Ruby on rails創建一個驗證並在任何地方使用

Question

我有一個rails應用程序，我想添加驗證字符的長度。

它在應用程序中使用的地方有text field，我在應用程序中有很多模型。放在模型中的任何地方似乎都是重複的。

還能有我可以做一個單一的驗證和模型任何地方使用任何方法。

我不能只是得到一點，所以我還沒有嘗試到現在 解決方案將非常感激。如果有人可以提供答案

Answer 1

您可以創建一個custom validation

# app/validators/char_validator.rb 
class CharValidator < ActiveModel::EachValidator 
  def validate_each(record, attribute, value) 
    # your validation 
  end 
end 

# app/models/foo.rb 
class Foo < ActiveRecord::Base 
  validates :bar, presence: true, char: true 
end 

Answer 2

你可以使用這個問題。你可以把你方法在app/models/concerns文件夾，例如，因爲是Validatable模塊

module Concerns::Validatable 
    extend ActiveSupport::Concern 

    def format_website 
    Write your validation code here. 
    end 

end 

然後將其包含在每個模型作爲

include Concerns::Validatable 

Answer 3

一種方法是使用validates_with與自定義的驗證類一起。更多信息可在http://guides.rubyonrails.org/active_record_validations.html#validates-with

# Your custom validator. Validates that field is all capital letters 
class ShoutingValidator < ActiveModel::Validator 
    def validate(record) 
    options[:fields].each do |field| 
     original_value = record.public_send(field).to_s 
     uppercase_value = original_value.upcase 
     if original_value != uppercase_value 
     record.errors.add(field, "#{field} must be shouted in all capital letters.") 
     end 
    end 
    end 
end 

# Will likely be ActiveRecord::Base in your case Only difference would be to 
# remove the `include` and `attr_accessor` lines 
class Book 
    include ActiveModel::Model 
    validates_with ShoutingValidator, fields: [:title, :author] 
    attr_accessor :title, :author 
end 

# Second class to show that the same custom validator can be used 
# for other class and field too. 
class Person 
    include ActiveModel::Model 
    validates_with ShoutingValidator, fields: [:name] 
    attr_accessor :name 
end 

# When writing it, i created a test to see that it works 
describe Book do 
    it 'has shouting title' do 
    expect(described_class.new title: 'Non shout').to_not be_valid 
    end 
end