回形针和嵌套属性问题答案

【问题标题】：paperclip and nested attributes problem回形针和嵌套属性问题
【发布时间】：2011-03-28 23:35:19
【问题描述】：

使用回形针上传文件。我有项目、附件和关联表。我拥有可以上传文件的所有内容，但是当它进入项目控制器时，它会寻找方法attachment_file_name，但是，我相信它应该是user_file_file_name，因为:user_file 是附件模型用于has_attachment 语句。这是生产日志：

Started POST "/projects" for 136.152.181.137 at Mon Mar 28 16:23:28 -0700 2011
  Processing by ProjectsController#create as HTML
  Parameters: {"commit"=>"Create Project", "authenticity_token"=>"xh0Ld2RKyJ6EF9jLNl3D+r1m50lKv389NCIor3H4fag=", "utf8"=>"?~\~S", "project"=>{"name"=>"Upload Test", "icon_id"=>"1", "categories_attributes"=>{"0"=>{"name"=>"Category 1", "_destroy"=>"false"}}, "content"=>"skee", "description"=>"description", "attachments_attributes"=>{"0"=>{"name"=>"name", "user_file"=>#<ActionDispatch::Http::UploadedFile:0x2aaaaf6b0fd8 @tempfile=#<File:/tmp/RackMultipart20110328-18838-4wasuv-0>, @headers="Content-Disposition: form-data; name=\"project[attachments_attributes][0][user_file]\"; filename=\"resized_DSCF0229.JPG\"\r\nContent-Type: image/jpeg\r\n", @original_filename="resized_DSCF0229.JPG", @content_type="image/jpeg">}}}}
Completed   in 6ms

NoMethodError (undefined method `attachment_file_name' for #<Attachment:0x2aaaaf6a0638>):
  app/controllers/projects_controller.rb:48:in `create'
  app/controllers/projects_controller.rb:47:in `create'

如果有帮助，以下是模型：

class Project < ActiveRecord::Base
  has_many :project_file_assocs
  has_many :attachments, :through => :project_file_assocs
  accepts_nested_attributes_for :attachments
  attr_accessible :attachments_attributes
...
end


class Attachment < ActiveRecord::Base
  has_attached_file :user_file
  validates_attachment_presence :attachment

  has_many :project_file_assocs 
  has_many :projects, :through => :project_file_assocs
  attr_accessible :name, :description, :user_file_file_name, :user_file_content_type, :user_file_file_size
  #attr_accessible :name, :description, :user_file
end


class ProjectFileAssoc < ActiveRecord::Base
   belongs_to :attachment
   belongs_to :project
end

它为什么要寻找那个方法？提前感谢您的帮助！

这里是projects_controller.rb的创建方法：

def create
    @project = Project.new(params[:project])

    respond_to do |format|
      if @project.save
        format.html { redirect_to(@project, :notice => 'Project was successfully created.') }
        format.xml  { render :xml => @project, :status => :created, :location => @project }
      else
        format.html { render :action => "new" }
        format.xml  { render :xml => @project.errors, :status => :unprocessable_entity }
      end
    end
  end

【问题讨论】：

如果是生产日志，在开发环境中不会报同样的错误吗？

标签： ruby-on-rails ruby-on-rails-3 associations paperclip nested-attributes

【解决方案1】：

我认为问题出在附件模型中：

class Attachment < ActiveRecord::Base
  has_attached_file :user_file
  validates_attachment_presence :attachment

试试

  validates_attachment_presence :user_file

【讨论】：