paperclip - Rails with Paperclip 忽略空附件

Question

我正在使用带有导轨的回形针并且它工作正常，但是我的问题是更新时如果我不重新选择图像，那么它会将记录保存为 nil。这是我的代码:

<div class="form-group">
  <div class="media">
    <%= image_tag program_avatar(b), :id => 'avatar', :class => 'thumbnail media-object pull-left', :height => 100, :width => 100 %>
    <div class="media-body padding-top-40">
      <%= b.file_field :avatar, :class => 'file-upload' %>
    </div>
  </div>
</div>

<div class="form-group">
  <div class="media">
    <%= image_tag program_banner(b), :class => 'thumbnail media-object pull-left', :height => 100, :width => 300 %>
    <div class="media-body padding-top-40">
      <%= b.file_field :banner, :class => 'file-upload' %>
    </div>
  </div>
</div>

和 Controller :

respond_to do |format|
  if @program.update(program_params)
    format.html { redirect_to(program_path(@program), :notice => "Program updated") }
    format.js { render :json => @program.json }
  else
    format.html { render :new, :notice => "Error please try again" }
    format.js { render :json => "Error please try again" }
  end
end

型号:

书籍型号:

has_one :book_content, :dependent => :destroy  
accepts_nested_attributes_for :book_content, :allow_destroy => true

Book_content 模型:

has_attached_file :avatar, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "/images/:style/missing.png"
has_attached_file :banner, :styles => { :header => "600x150", :setting => "300x100"  }, :default_url => "/images/:style/found.jpeg"
belongs_to :book

这是一个嵌套表单，但因为它有多个附件所以我不能使用 reject_if
如果没有选择文件，如何告诉回形针保留原始文件？

谢谢

Answer 1

经过一番研究，我发现我的问题没有通过 id在参数中，所以我有这个:

params.require(:book).permit(:book_name, book_content_attributes: [:media, :rating, :book_id])

改成这样:

params.require(:book).permit(:book_name, book_content_attributes: [:id, :media, :rating, :book_id])

注意添加的 :id ，现在它工作正常。