Question

我有一个名为Resource的模型，配置有：

class Resource < ActiveRecord::Base    
has_many_attached :assets
end

我在resources_controller.rb中创建了一个动作，如下所示：

  def delete_asset_attachment
    @asset = ActiveStorage::Attachment.find_by(params[:id])
    logger.debug "The value of @asset is #{@asset}"
    @asset.purge
    redirect_to @resource
  end

我有一个显示资源并循环浏览附加资产的表格。下面是循环遍历资产的代码片段：

<% @resource.assets.each do |asset| %>
<%= link_to 'Remove Attachment', delete_asset_attachment_resource_url(@resource, asset.id), method: :delete, data: { confirm: 'Are you sure?' } %>
<% end %>

/ resources页面正确显示资源以及附加资产。但是，当我尝试单击链接以删除其中一项资产时，收到错误消息：“未定义的方法'purge'为nil：NilClass”。但是，在控制台中，我看到附件存在。

这是服务器控制台的输出：

    Started DELETE "/resources/10/delete_asset_attachment.18" for ::1 at 2019-03-09 17:27:28 -0500
Processing by ResourcesController#delete_asset_attachment as 
  Parameters: {"authenticity_token"=>"EFZO5V9Bii3dId0I6hn5DajFR5WJYZBc8qPAAi5ppQOFW3cws5I4FjyVP9IlvA+2a2kKUJhobnqd8atG4L3k+g==", "id"=>"10"}
  Resource Load (0.1ms)  SELECT  "resources".* FROM "resources" WHERE "resources"."id" = ? LIMIT ?  [["id", 10], ["LIMIT", 1]]
  User Load (0.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT ?  [["id", 1], ["LIMIT", 1]]
  ActiveStorage::Attachment Load (0.1ms)  SELECT  "active_storage_attachments".* FROM "active_storage_attachments" WHERE (10) LIMIT ?  [["LIMIT", 1]]
The value of @asset is #<ActiveStorage::Attachment:0x00007f8d7bd4df68>
  ActiveStorage::Blob Load (0.2ms)  SELECT  "active_storage_blobs".* FROM "active_storage_blobs" WHERE "active_storage_blobs"."id" = ? LIMIT ?  [["id", 27], ["LIMIT", 1]]
Completed 500 Internal Server Error in 5ms (ActiveRecord: 0.6ms)

NoMethodError - undefined method `purge' for nil:NilClass:

::1 - - [09/Mar/2019:17:27:28 EST] "POST /resources/10/delete_asset_attachment.18 HTTP/1.1" 500 76939
http://localhost:3000/resources/10/edit -> /resources/10/delete_asset_attachment.18
Started POST "/__better_errors/70da0e976a425fce/variables" for ::1 at 2019-03-09 17:27:28 -0500
  ActiveStorage::Blob Load (0.2ms)  SELECT  "active_storage_blobs".* FROM "active_storage_blobs" WHERE "active_storage_blobs"."id" = ? LIMIT ?  [["id", 27], ["LIMIT", 11]]
::1 - - [09/Mar/2019:17:27:28 EST] "POST /__better_errors/70da0e976a425fce/variables HTTP/1.1" 200 36499
http://localhost:3000/resources/10/delete_asset_attachment.18 -> /__better_errors/70da0e976a425fce/variables

我到处都在寻找解决方案。存在于stackoverflow上的夫妇并没有解决我的问题。在Rails指南或Web上的其他任何地方都缺少用于处理删除附件的特定细节和示例，这令人难以置信。不胜感激。

更新：这是我的routes.rb：

resources：resources做获得“列表”，：on =>：collection ：sort，on：：collection 会员做删除：delete_asset_attachment 结束结束

更新2：rails路由输出

resources GET    /resources(.:format)                                                                     resources#index
                             POST   /resources(.:format)                                                                     resources#create
                new_resource GET    /resources/new(.:format)                                                                 resources#new
               edit_resource GET    /resources/:id/edit(.:format)                                                            resources#edit
                    resource GET    /resources/:id(.:format)                                                                 resources#show
                             PATCH  /resources/:id(.:format)                                                                 resources#update
                             PUT    /resources/:id(.:format)                                                                 resources#update
                             DELETE /resources/:id(.:format)                                                                 resources#destroy

Answer 1

我已经能够完成这项工作。啊经过数小时的挫折之后，仓促。

阅读本文后将事情拼凑在一起 Deleting ActiveStorage Attachments From the Controller, 3 Ways

我将控制器代码更改为：

  def delete_asset_attachment
    @resource.assets.find_by(params[:attachment_id]).purge
    redirect_to @resource
  end

和我的形式如下：

   <% @resource.assets.each do |asset| %>
      <%= asset.filename %>
      <%= link_to 'Remove Attachment', delete_asset_attachment_resource_url(@resource, asset.id), method: :delete, data: { confirm: 'Are you sure?' } %>
   <% end %>

我认为问题在于我的旧代码行：

@asset = ActiveStorage::Attachment.find_by(params[:id])

...仅传递@resource ID，但未找到附件。关键是更改此行：

@resource.assets.find_by(params[:attachment_id]).purge

...更正确地指向正确的资源，然后指向要清除的特定资产（附件）。

Answer 2

修正find_by的语法并改用安全的＆符

    @asset = ActiveStorage::Attachment.find_by(params[:id])
    @asset.purge

尝试：

    @asset = ActiveStorage::Attachment.find_by(id: params[:id])
    @asset&.purge

无法清除活动存储附件

2 个答案: