Rails的文件上传（回形针）的编辑 [英] Rails file upload (paperclip) on edit

问题描述

我自己做了一个简单的Rails博客类的应用程序，我用回形针上传图片files.I拥有一切工作的罚款和花花公子。我甚至把它迷上了一个S3桶等漂亮吧？

I made myself a simple rails blogging-type app where I use Paperclip to upload image files.I have everything working fine and dandy. I even have it hooked up to an S3 bucket, etc. Spiffy right?

但我想不通编辑/更新帖子的时候该怎么办。由于是代表现在，我只有这个领域对我的表单模板：

But I can't figure what to do when EDITING/UPDATING a post. As is stands now, all I have is this field on my form template:

= f.file_field :image

所以，说在后/ 5 /编辑即使有一个previously附加的图像，该字段显示没有文件选择。

So, say on "post/5/edit" even if there's a previously attached image, the field displays "No file chosen".

更糟糕的是，有没有明显的方法来清除当前的图像，如果我改变了主意，不想附加的图像。

Even worse, there's no apparent way to clear out current image if I change my mind and don't want to attach an image.

我如何使这个多一点人性化，并确保当前图像 - 文字/网址是好的 - 显示为文本字段和/或用户的值可以改变当前图像无

How do I make this a little more user-friendly and make sure the current image -- text/url is fine -- shows up as the value in the text field and/or the user can change the current image to none.

推荐答案

有关Rails3这里就是我做的。对不起，我没有使用过Rails4呢。

For Rails3 here's what I do. Sorry, I haven't used Rails4 yet.

要显示给用户，如果他们已经上传的文件，这样在您的看法：

To display to the user if they have already uploaded a file, do this in your view:

<% if @blog.image.exists? %>
  <%= image_tag @blog.image.url(:thumb) %><br/>
<% end %>
<%= f.file_field :image %>

随后，以允许用户删除当前文件的上传添加到您的视图（如果块中）：

Then, to allow for the user to remove the current upload add this to your view (inside that if block):

<%= f.check_box :delete_image %>Delete Image<br/>

和你处理这个复选框，在模型中：

And you handle that checkbox in your model:

  before_validation { image.clear if @delete_image }

  def delete_image
    @delete_image ||= false
  end

  def delete_image=(value)
    @delete_image  = !value.to_i.zero?
  end

这样，如果用户设置的复选框，将清除图像上的下一个保存。

That way if the user sets the checkbox it will clear the image on the next save.

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