Rails - Refile - IO错误关闭流

Question

我有三个型号Product，Image，Post。帖子和产品有很多图像，这是多态的。当我尝试使用包含的图像创建新产品或帖子时，我得到：

IOError (closed stream):
  app/controllers/posts_controller.rb:18:in `create'

有趣的是：如果我创建产品或发布没有图像，然后回来编辑模型，我就可以上传图片没问题。

class Product < ActiveRecord::Base
  belongs_to :category
  has_many :images, as: :imageable, :dependent => :destroy
  accepts_attachments_for :images, attachment: :file
  has_many :line_items
end


class Post < ActiveRecord::Base
  validates_presence_of :title, :body
  has_many :images, as: :imageable, :dependent => :destroy
  accepts_attachments_for :images, attachment: :file
end



class Image < ActiveRecord::Base
  belongs_to :imageable, polymorphic: true
  attachment :file
end

class PostsController < ApplicationController

  load_and_authorize_resource

  def index
     @posts = Post.all.order("created_at desc")
  end

  def show
    @post = Post.find(params[:id])
  end

  def new
    @post = Post.new
  end

  def create
    @post = Post.new(post_params)
    if @post.save
      redirect_to @post
    else
      render 'new'
    end
  end

  def edit
    @post = Post.find(params[:id])
  end

  def update
    @post = Post.find(params[:id])
    if @post.update_attributes!(post_params)
      redirect_to @post
    else
      render "edit"
    end
  end

  private

  def post_params
      params.require(:post).permit(:title, :subtitle, :body, images_files: [])
  end

end

这是/posts/_form.html.slim

.form
  = form_for @post do |post|
    = post.text_field :title
    = post.label :title
    = post.text_field :sub_title
    = post.label :subtitle

    div
      - @post.images.each do |image|
        .photo
          = attachment_image_tag(image, :file, :fill, 150, 150)
          div
            = check_box_tag "images_ids[]", image.id, false, :id => "image_#{image.id}"
            label remove
      div
        = post.attachment_field :images_files, multiple: true
      label Photos

    .edit-section
      label Body
      = post.text_area :body, :class => "edit", :style => "display: none"
      .field.editable[contenteditable="true" data-field-id="body"]
        - if @post.body?
          = @post.body.html_safe
        - else
          p
            | Body goes here
    .button-box
      = post.submit :class => "button primary"
      = link_to "Cancel", :back, :class => "button cancel"