从2.3

Question

我在Rails 4.2中重写了一个旧的Rails 2.3应用程序，保留了数据库内容。

到目前为止一切顺利。

旧应用程序使用Paperclip 2.3插件并将文件存储在S3上。 在新的应用程序上，我安装了Paperclip 4.3.6 gem和aws-sdk 2.3。

我的问题：当我为任何现有用户调用头像时，例如

User.first.avatar 

应用返回：

undefined method `new' for nil:NilClass

我已经安装了ImageMagik并添加了

Paperclip.options[:command_path] = "/usr/local/bin/"

到我的development.rb

以下是我的型号/控制器：

user.rb

class User < ActiveRecord::Base

    has_attached_file :avatar, :styles => {:micro => "32x32#", :thumb => "50x50#", :big_thumb => "80x80#", :small => "220x220>", :featured => "220x220#", :medium => "600x600>"}#, :default_url => 'http://s3.amazonaws.com/ccu-static/file.small.png'

    validates_attachment_content_type :avatar, :content_type => ['image/jpeg', 'image/pjpeg', 'image/jpg', 'image/png', 'image/gif'], :if => lambda {|user| user.avatar_file_name}

end

users_controller.rb

class UsersController < ApplicationController

private

  def user_params
    params.require(:user).permit(:avatar)
  end

end

config＆gt;初始化器＆gt; paperclip_defaults.rb

module Paperclip
  class Attachment
    def self.default_options
      @default_options ||= {
        :storage           => :s3,
        :url               => "/system/:attachment/:id/:style/:filename",
        :path              => "/:attachment/:id/:style/:filename",
        :styles            => {},
        :processors        => [:thumbnail],
        :convert_options   => {},
        :default_url       => "/images/missing.:style.gif", #"http://s3.amazonaws.com/ccu-static/missing.:style.png", 
        :default_style     => :original,
        :s3_credentials => "#{Rails.root}/config/s3.yml",
        :whiny             => Paperclip.options[:whiny] || Paperclip.options[:whiny_thumbnails]
      }
    end
  end
end

config＆gt; S3.yml

production:
  bucket: ...
  access_key_id: ...
  secret_access_key: ...
development:
  bucket: ...
  access_key_id: ...
  secret_access_key: ...

schema.rb

  create_table "users", force: :cascade do |t|
    ...
    t.string   "avatar_file_name",           limit: 255
    t.integer  "avatar_file_size"
    t.string   "avatar_content_type",        limit: 255
    t.datetime "avatar_updated_at"
  end

视图：

<%= image_tag(@top_players_score[0].avatar.url(:thumb)) if @top_players_score[0].avatar %>

无论如何，即使从具有基本功能的控制台我也会得到同样的错误：

user.avatar