Ruby-on-rails 为什么我在安装 PaperClip 时得到“has_attached_file”的“未定义方法”？
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Why do I get an "undefined method for `has_attached_file` when installing PaperClip?
提问by bgadoci
I just installed the plugin for Paperclip and I am getting the following error message but I am not sure why:
我刚刚安装了 Paperclip 插件，但收到以下错误消息，但我不知道为什么：
NoMethodError (undefined method `has_attached_file' for #<Class:0x10338acd0>):
/Users/bgadoci/.gem/ruby/1.8/gems/will_paginate-2.3.12/lib/will_paginate/finder.rb:170:in `method_missing'
app/models/post.rb:2
app/controllers/posts_controller.rb:50:in `show'
It is referencing the will_paginate gem. From what I can find, it seems that either there is something wrong with my PostsController#indexor perhaps a previously attempt at installing the gem instead of the plugin, in which case I have read I should be able to remedy through the /config/environments.rbfile somehow.
它引用 will_paginate gem。据我所知，似乎是我的PostsController#index或之前尝试安装 gem 而不是插件有问题，在这种情况下，我已经阅读过我应该能够以/config/environments.rb某种方式修复该文件。
I didn't think that previous gem installation would matter as I did it in an old version of the site that I trashed before installing the plugin. In the current version of the site I show that the table has been updated with the Paperclip columns after migration. Here is my code:
我不认为以前的 gem 安装会很重要，因为我在安装插件之前丢弃的旧版本站点中这样做了。在该站点的当前版本中，我显示该表在迁移后已使用 Paperclip 列进行更新。这是我的代码：
PostsConroller#show:
PostsConroller#show：
def show
@post = Post.find(params[:id])
respond_to do |format|
format.html # show.html.erb
format.xml { render :xml => @post }
end
end
Postmodel:
Post模型：
class Post < ActiveRecord::Base
has_attached_file :photo
validates_presence_of :body, :title
has_many :comments, :dependent => :destroy
has_many :tags, :dependent => :destroy
has_many :votes, :dependent => :destroy
belongs_to :user
after_create :self_vote
def self_vote
# I am assuming you have a user_id field in `posts` and `votes` table.
self.votes.create(:user => self.user)
end
cattr_reader :per_page
@@per_page = 10
end
/views/posts/new.html.erb:
/views/posts/new.html.erb：
<h1>New post</h1>
<%= link_to 'Back', posts_path %>
<% form_for(@post, :html => { :multipart => true}) do |f| %>
<%= f.error_messages %>
<p>
<%= f.label :title %><br />
<%= f.text_field :title %>
</p>
<p>
<%= f.label :body %><br />
<%= f.text_area :body %>
</p>
<p>
<%= f.file_field :photo %>
</p>
<p>
<%= f.submit 'Create' %>
</p>
<% end %>
回答by Raunak
It is very important that you restart your server after installing new gems/plugins. This should solve your problem
安装新的 gems/插件后重新启动服务器非常重要。这应该可以解决您的问题
回答by Eimantas
I'd suggest installing paperclip gem. Then you'd just need to add config.gem 'paperclip'to your environment.rb and run sudo rake gems:install.
我建议安装回形针 gem。然后你只需要添加config.gem 'paperclip'到你的 environment.rb 并运行sudo rake gems:install.
回答by kotesh
create the file paperclip.rb inside the config/initializers/paperclip.rb
在 config/initializers/paperclip.rb 中创建文件 paperclip.rb
Add the below lines and restart the server
添加以下行并重新启动服务器
require "paperclip/railtie"
需要“回形针/轨道”
Paperclip::Railtie.insert
回形针::Railtie.insert
回答by chris finne
I got this error spontaneously on 2 different dev machines after Paperclip was working fine for weeks.
在 Paperclip 正常工作数周后，我在 2 台不同的开发机器上自发地收到了这个错误。
spring stop
spring stop
then restarted my rails console was needed
然后重新启动需要我的 rails 控制台
回答by TheRightChoyce
I guess this should have been obvious, but I'm using mongo/mongoid as my data layer and needed to install mongoid paperclipfor it to work.
我想这应该是显而易见的，但我使用 mongo/mongoid 作为我的数据层，并且需要安装mongoid 回形针才能使其工作。
