使用Ruby 1.8.7的未定义方法`has_attached_file’，带有paperclip 2.3.8 gem for Rails 2

我正在尝试使用我的rails应用程序中的paperclip插件上传post的图像。 我在Ubuntu 10.04操作系统上使用Rails 2.0.2和ruby 1.8.7用于项目特定目的。

我指的是以下教程： –

1. http://railscasts.com/episodes/134-paperclip?view=comments

2. http://jimneath.org/2008/04/17/paperclip-attaching-files-in-rails.html

我通过以下方式在paperclip插件上做了一个git clone： – https://github.com/thoughtbot/paperclip ，但像ruby script/generate paperclip group_post photo这样的命令没有为它生成迁移。 然后，我通过ruby脚本/生成创建了相同的迁移，并上传了我的表group_posts的相应列。

然后我尝试安装gem，因为我使用activerecord和activesupport 2.0.2我使用了rubygems.org的paperclip 2.3.8 gem。未定义的方法错误仍然存​​在，我真的无法弄清楚为什么。

现在这里..命令ruby script/generate paperclip group_post photo对我来说非常好。

我得到的当前错误看起来像这样： –

 undefined method `has_attached_file' for # 

我观察到这个行为的一个有趣的事情就是当我使用IRB时， require 'paperclip'返回true但我想知道为什么他们无法检测我的rails应用程序中插件附带的方法。

该应用程序跟踪是： –

 /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activerecord-2.0.2/lib/active_record/base.rb:1532:in `method_missing_without_paginate' vendor/plugins/will_paginate/lib/will_paginate/finder.rb:170:in `method_missing' app/models/group_post.rb:9 app/controllers/groups_controller.rb:27:in `show' 

以下是完整跟踪 ： –

 /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activerecord-2.0.2/lib/active_record/base.rb:1532:in `method_missing_without_paginate' vendor/plugins/will_paginate/lib/will_paginate/finder.rb:170:in `method_missing' app/models/group_post.rb:9 /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:203:in `load_without_new_constant_marking' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:203:in `load_file' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in `new_constants_in' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:202:in `load_file' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:94:in `require_or_load' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:248:in `load_missing_constant' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:453:in `const_missing_not_from_s3_library' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/aws-s3-0.6.2/lib/aws/s3/extensions.rb:206:in `const_missing' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:465:in `const_missing' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:471:in `send' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:471:in `const_missing' app/controllers/groups_controller.rb:27:in `show' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/base.rb:1158:in `send' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/base.rb:1158:in `perform_action_without_filters' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/filters.rb:697:in `call_filters' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/filters.rb:689:in `perform_action_without_benchmark' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/1.8/benchmark.rb:293:in `measure' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/rescue.rb:199:in `perform_action_without_caching' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/caching.rb:678:in `perform_action' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activerecord-2.0.2/lib/active_record/connection_adapters/abstract/query_cache.rb:33:in `cache' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activerecord-2.0.2/lib/active_record/query_cache.rb:8:in `cache' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/caching.rb:677:in `perform_action' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/base.rb:524:in `send' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/base.rb:524:in `process_without_filters' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/filters.rb:685:in `process_without_session_management_support' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/session_management.rb:123:in `process_without_test' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/test_process.rb:15:in `process' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/base.rb:388:in `process' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:171:in `handle_request' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:115:in `dispatch' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:126:in `dispatch_cgi' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:9:in `dispatch' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/bin/mongrel_rails:281 /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:489:in `load' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:489:in `load' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in `new_constants_in' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:489:in `load' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/commands/servers/mongrel.rb:64 /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in `require' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in `new_constants_in' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in `require' /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/commands/server.rb:39 /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 

我的groups_controller.rb show方法如下所示，第27行是@group_post = GroupPost.new(params[:group_post]) ： –

  def show @investor_group = InvestorGroup.find(params[:id]) @members = @investor_group.activated_members # code taken from discuss method investor_id = session['investor_id'] @investor = Investor.find(investor_id) @members = @investor_group.activated_members unless @current_user.is_an_existing_member_of_group(@investor_group) flash[:notice] = "Please join this group to participate in discussions" redirect_to :action => :show, :id => @investor_group and return else @group_post = GroupPost.new(params[:group_post]) # line 27, tried GroupPost.create also.. seems to be of no avail.. end #@group_post = GroupPost.new(params[:group_post]) @group_post.investor_group_id = @investor_group.id @group_post.post_by = investor_id unless @group_post.message.blank? if @group_post.save flash[:notice] = 'Post was successfull' else flash[:notice] = 'Post was not successfull' end #redirect_to :action => :show, :id => @investor_group and return to change.. appropriately.... end #if @group_post.message.blank? # flash[:notice] = 'Post can\'t be blank.' #end @group_all_posts = GroupPost.find(:all, :conditions => [ 'investor_group_id = ?', "#{@investor_group.id}" ], :order => 'created_at DESC') # code taken from discuss method end 

group_post模型如下所示，第9行包含以下代码has_attached_file：photo： –

class GroupPost <ActiveRecord :: Base has_many：group_comments belongs_to：investor_group validates_presence_of：message

#include Paperclip需要“paperclip”#Paperclip has_attached_file：photo＃line 9

结束

我的视图文件的一部分，我试图上传图片以及post如下： –

  {:action => :show},:html => {:multipart => 'true'},:id => 'new_post' do |f| -%> 
Start Discussion:
  
  

我尝试了以下内容： –

• 为什么在安装PaperClip时会得到“has_attached_file”的“未定义方法”？

这个选项似乎不适用于我的情况，因为它似乎使用更高的Rails版本

• Paperclip安装后未定义的方法has_attached_file？

  我尝试重新启动我的服务器，但它没有解决我的问题;

• https://github.com/thoughtbot/paperclip/issues/192

我试过包括Paperclip – 但它似乎对我的情况没有帮助……

我在我的group_post.rb和我的environment.rb文件中添加了一个require，需要“paperclip”。 我仍然得到一个未定义的方法错误。 我不知道为什么..

• NoMethodError：未定义的方法`has_attached_file’

在提到这个时我尝试了Imumar的回形针分支，我在git克隆之后手动将它粘贴在我的vendor / plugins目录中。我得到了以下错误（我有一种感觉肯定会出现依赖性问题，因为他的版本可能是仅与更高的rails版本兼容：

 mohnish@mohnish-desktop:~/UP/dev$ ruby script/server -p 4000 => Booting Mongrel (use 'script/server webrick' to force WEBrick) => Rails application starting on http://0.0.0.0:4000 => Call with -d to detach => Ctrl-C to shutdown server ** Starting Mongrel listening at 0.0.0.0:4000 ** Starting Rails with development environment... Exiting /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:263:in `load_missing_constant': uninitialized constant Paperclip::CallbackCompatability::Rails20 (NameError) from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:453:in `const_missing' from /home/mohnish/UP/dev/vendor/plugins/paperclip/lib/paperclip.rb:118:in `included' from /home/mohnish/UP/dev/vendor/plugins/paperclip/lib/paperclip.rb:364:in `include' from /home/mohnish/UP/dev/vendor/plugins/paperclip/lib/paperclip.rb:364:in `send' from /home/mohnish/UP/dev/vendor/plugins/paperclip/lib/paperclip.rb:364 from /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' from /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in `require' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in `new_constants_in' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in `require' from /home/mohnish/UP/dev/vendor/plugins/paperclip/init.rb:1:in `evaluate_init_rb' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/rails/plugin.rb:79:in `evaluate_init_rb' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/core_ext/kernel/reporting.rb:11:in `silence_warnings' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/rails/plugin.rb:75:in `evaluate_init_rb' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/rails/plugin.rb:39:in `load' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/rails/plugin/loader.rb:33:in `load_plugins' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/rails/plugin/loader.rb:32:in `each' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/rails/plugin/loader.rb:32:in `load_plugins' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/initializer.rb:189:in `load_plugins' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/initializer.rb:105:in `process' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/initializer.rb:49:in `send' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/initializer.rb:49:in `run' from /home/mohnish/UP/dev/config/environment.rb:16 from /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' from /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in `require' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in `new_constants_in' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in `require' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:147:in `rails' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/bin/mongrel_rails:113:in `cloaker_' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:149:in `call' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:149:in `listener' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/bin/mongrel_rails:99:in `cloaker_' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:50:in `call' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:50:in `initialize' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/bin/mongrel_rails:84:in `new' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/bin/mongrel_rails:84:in `run' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/mongrel-1.1.5/bin/mongrel_rails:281 from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:489:in `load' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:489:in `load' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in `new_constants_in' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:489:in `load' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/commands/servers/mongrel.rb:64 from /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' from /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in `require' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in `new_constants_in' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in `require' from /home/mohnish/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.0.2/lib/commands/server.rb:39 from /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' from /home/mohnish/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' from script/server:3 mohnish@mohnish-desktop:~/UP/dev$ 

我真的很想知道我哪里出错了..

任何建议/见解将受到高度赞赏。 这对我来说很紧急，因为我有部署到期，我很乐意得到及时的答案/答复。

非常感谢..

Answer 1

好的，首先，只是为了覆盖“明显的”基础：做“ls vendor / plugins”只是为了确保某些版本的回形针实际上在你的插件目录中，因此你的应用程序可以访问它。

其次 – 模型中的“需要回形针”对我来说似乎不对。 我猜这需要应该放在你的环境中。 尝试将它放在config / environments.rb的末尾。

第三（也许与您的具体问题无关） – 2.0.2是一个非常古老的rails版本。 如果你能升级到2.3.5，或者至少升级到2.2.x. 据我们所知 – 你可能会遇到一个问题，因为你有一个新版本的回形针和一个旧版本的导轨……这确实有所作为。

您发布的许多其他链接指的是Rails3之前的安装 – 由于这个原因，他们的问题的解决方案将与您的不同。

Answer 2

稍微相关，决定把这个放在这里为未来的googlers。

在Ruby 1.8.7上使用Rails 2.3.14和bundler。 正如thinkbot所建议我使用paperclip 2.7，即我的gemfile包含：

 gem "paperclip", "~> 2.7.0" 

我也收到了“未定义的方法”错误。 为我修复的是将paperclip.rb文件放入包含以下内容的config/initializers中：

 require "paperclip/railtie" Paperclip::Railtie.insert 

希望这会让人有点头疼。