Question

我正在使用ActiveModel使我的无表格模型感觉像ActiveRecord模型。我正在使用自定义商店，我需要能够验证记录的唯一性。

如何使用ActiveModel实现所需的唯一性检查？

Answer 1

我最终做了这样的事情：

class Theme < Base

  include ActiveModel::Validations

  attr_accessor :id, :name
  validate      :uniqueness_of_theme_name, :on => :create

  def initialize(attrs = {})
    attrs.each do |name, value|
      send("#{name}=", value)
    end
  end

  def uniqueness_of_theme_name
    errors.add(:name, "name is already in use") unless Theme.find_by_name(name).nil?
  end

  def self.find_by_name(name)
    return store.find({ 'name' => "/^#{name}$/i" }).any?
  end

  def self.create(attributes = {})
    theme = Theme.new(attributes)
    theme.save

    return theme
  end

  def persisted?
    id && !id.nil?
  end

  def save()
    # only call validation during create context
    context = persisted? :update : :create
    false if invalid?(context)
    store.save(self)
    true
  end

  def self.create(attrs = {})
    theme = Theme.new(attrs)
    theme.save
    theme
  end

end

也许有人可以告诉我这是否是正确的方法

Answer 2

检查此railscast，它可能会有所帮助

http://railscasts.com/episodes/193-tableless-model

完成模型后，添加验证，然后添加@ model.valid？

Answer 3

ActiveModel可以根据另一个railscasts使用，这更适合该用例。

class Theme

  include ActiveModel::Validations
  include ActiveModel::Conversion
  extend ActiveModel::Naming

  attr_accessor :id, :name

  validates :name, uniqueness: true, on: :create

  def initialize(attributes = {})
    attributes.each do |name, value|
      send("#{name}=", value)
    end
  end

  def persisted?
    false
  end
end

如何在ActiveModel中使用validates_uniqueness_of？

3 个答案: