驗證Ruby ActiveModel ::驗證和ActiveModel :: Errors設置功能

Question

我已經被授權編寫一個函數來驗證下面代碼中的名字和姓氏不一樣。我必須使用ActiveModel :: Validation和ActiveModel :: Errors，如果兩個名稱相同，它應該給出一個錯誤消息「Nope」。

我很少紅寶石的經驗，但這裏是我的嘗試：

require 'active_model' 

class Person 
    include ActiveModel::Validations 
    validate :test 
    validates_presence_of :first 
    validates_presence_of :last 

    def initialize(first, last) 
     @first = first 
     @last = last 
    end 

    def test 
     errors.add_to_base("Nope") if @first == @last 
    end 

end 

a = Person.new("James", "James") 
b = Person.new("James") 

所以我得到一個錯誤信息，當我嘗試實例b，但因爲我的功能是缺失的參數，這只是一個Ruby的錯誤。我相信這可能很簡單，但我會很感激任何幫助。

Answer 1

我想到了我自己的解決方案，這一點，我一直在尋找的是：

require 'active_model' 

class Person 
include ActiveModel::Validations 
attr_accessor :first, :last 
validate :first_does_not_equal_last 

def first_does_not_equal_last 
    if @first == @last 
    self.errors[:base] << "First cannot be the same as Last" 
    end 
end 

def initialize(first, last) 
    @first = first 
    @last = last 
end 

end 

Answer 2

檢查https://github.com/rails/rails/tree/master/activemodel更多信息：

require 'active_model' 

class TestValidator < ActiveModel::Validator 
    def validate(record) 
    record.errors[:base] = "First and last can't be the same" if record.first.presence == record.last.presence 
    end 
end 

class Person 
    include ActiveModel::Model 

    attr_accessor :first, :last 

    validates_presence_of :first, :last 
    validates_with TestValidator 
end 

p = Person.new(first: "Nick", last: "Nick") 
puts p.valid? # => false 
puts p.errors.full_messages # => First and last can't be the same 

p = Person.new(first: "Nick", last: "Doe") 
puts p.valid? # => true