ruby-on-rails - 为多个对象分配当前用户？

Question

在我下面的代码中，我想将当前用户分配给创建的产品。

ProductsController.rb

def new
  @products = Array.new(2) { Product.new }   
end

def create_multiple
  params[:product][:user_id] = current_user.id
  Product.transaction do
    begin
      @products = Product.create!(params[:products].map {|_k, up| up.merge params[:product]})
      redirect_to :back, :notice => "Success!"
    rescue ActiveRecord::Rollback
      redirect_to :back, :notice => "An error occured, please try again."
    end
  end
end

new.html.erb

<%= form_tag create_multiple_products_path, :method => :post do %>

  <%= date_select("product", "purchase_date")  %>

  <% @products.each_with_index do |product, index| %>
     <%= fields_for "products[#{index}]", product do |up| %>
        <%= render "fields", :f => up %>
     <% end %>
  <% end %>

  <%= submit_tag "Done" %>
<% end %>

未分配 USER ID(当前用户)。关于如何分配它有什么想法吗？

Answer 1

你可以通过记住两个事实来消除这里的很多逻辑:create 将采用哈希数组来创建多个对象，而它的 bang 方法对应物 create!如果任何验证失败，将抛出异常。

def create_multiple
  # like clyfe said, do this in a transaction
  Product.transaction do
    begin
      @products = current_user.products.create!(
        # Hash#map returns an Array, so no need to use Hash#values
        params[:products].map { |_k, up| up.merge params[:product] }
      )

      # if create! is successful...
      redirect_to :back, :notice => "Success!"

    # if it's not successful it'll throw this exception, which we can rescue
    rescue ActiveRecord::Rollback
      redirect_to :back, :notice => "An error occured, please try again."
    end
  end
end

---

处理 create! 问题的一种方法是去除 before_filter 中的所有“空白”条目，例如:

before_filter :toss_blank_products

def toss_blank_products
  params[:products].reject! do |prod|
    # this logic may need to be more complex depending on the meaning of "blank"
    # for your model/form
    prod.values.all? &:blank
  end
end