Rails Carrierwave NoMethodError

Question

我试图在我的应用程序中实现Jcrop，但一直收到以下错误：

NoMethodError in PeopleController#update
undefined method `body' for nil:NilClass

我使用的是Rails 4.0.2、Ruby 2.0.0p0、Bootstrap 2.3.2、Jcrop 0.9.12、Rmagick 2.13.2

奇怪的是，如果我重新加载这个人的页面，裁剪后的图片会保存到S3中并显示在UI中。但是，每次我尝试裁剪图片时，都会发生这个错误。

这是我的人物模型。我已经用**标记了这一行，当错误生成时，它会在浏览器中突出显示。

class Person < ActiveRecord::Base
    validates_presence_of :fname, :lname, :company, :department, :title, :work_phone, :mobile, :office, :address, :city, :state, :zipcode, :country, :suite, :column

    attr_accessor :crop_x, :crop_y, :crop_w, :crop_h

    mount_uploader :photo, PhotoUploader

    after_update :crop_photo

  def crop_photo
    **photo.recreate_versions! if crop_x.present?**
  end
end

这是我的PhotoUploader.rb文件：

# encoding: utf-8

class PhotoUploader < CarrierWave::Uploader::Base

  # Include RMagick or MiniMagick support:
  include CarrierWave::RMagick
  # include CarrierWave::MiniMagick

  # Choose what kind of storage to use for this uploader:
  # storage :file
   storage :fog

   include CarrierWave::MimeTypes
   process :set_content_type

  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  def default_url
    # For Rails 3.1+ asset pipeline compatibility:
    ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))

    # "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  end

  # Process files as they are uploaded:
  # process :scale => [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end

  # Create different versions of your uploaded files:

  version :large do
    process :resize_to_limit => [600, 600]
  end

  version :thumb do
    process :crop
    process :resize_to_limit => [200, 200]
  end

  def crop
    if model.crop_x.present?
      resize_to_limit(600, 600)
      manipulate! do |img|
        x = model.crop_x.to_i
        y = model.crop_y.to_i
        w = model.crop_w.to_i
        h = model.crop_h.to_i
        img.crop!(x, y, w, h)
      end
    end
  end

  after :store, :remove_original_file

  def remove_original_file(p)
    if self.version_name.nil?
      self.file.delete if self.file.exists?
    end
  end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  # def extension_white_list
  #   %w(jpg jpeg gif png)
  # end

  # Create random filename the filename of the uploaded files:
  def filename
     "#{secure_token(10)}.#{file.extension}" if original_filename.present?
  end

  protected
  def secure_token(length=16)
    var = :"@#{mounted_as}_secure_token"
    model.instance_variable_get(var) or model.instance_variable_set(var, SecureRandom.hex(length/2))
  end
end

下面是我的控制器中的Update操作：

  def update
    # respond_to do |format|
      if @person.update(person_params)
        if params[:person][:photo].present?
          render :crop
        else
          redirect_to @person, notice: "Successfully updated person."
        end
      #   format.html { redirect_to @person, notice: 'Person was successfully updated.' }
      #   format.json { head :no_content }
      # else
      #   format.html { render action: 'edit' }
      #   format.json { render json: @person.errors, status: :unprocessable_entity }
      end
    # end
  end

这是我的表格：

<%= simple_form_for @person, :html => { :class => 'form-horizontal', :multipart => 'true' } do |f| %>


  <div class="upload">
    <!-- <div class="photo"> -->
        <%= image_tag @person.photo.url(:thumb).to_s %> 
    <!-- </div> -->
        <%= f.file_field :photo, label: 'Upload Photo' %>
    </div>

  <%= f.input :ntid, label: 'NTID:', :input_html => { :readonly => true } %>
  <%= f.input :fname, label: 'First Name:' %>
  <%= f.input :mname, label: 'Middle Name:' %>
  <%= f.input :lname, label: 'Last Name:' %>
  <%= f.input :company, label: 'Company:' %>
  <%= f.input :department, label: 'Department:' %>
  <%= f.input :title, label: 'Title:' %>
  <%= f.input :email, label: 'E-Mail:' %>
  <%= f.input :work_phone, label: 'Work Phone:' %>
  <%= f.input :mobile, label: 'Mobile Phone:' %>
  <%= f.input :fax, label: 'FAX:' %>
  <%= f.input :office, label: 'Office:' %>
  <%= f.input :address, label: 'Address:' %>
  <%= f.input :city, label: 'City:' %>
  <%= f.input :state, collection: [ "Alabama", "Alaska", "Arizona", "Arkansas", "California", "Colorado", "Connecticut", "Delaware", "District of Columbia", "Florida", "Georgia", "Hawaii", "Idaho", "Illinois", "Indiana", "Iowa", "Kansas", "Kentucky", "Louisiana", "Maine", "Maryland", "Massachusetts", "Michigan", "Minnesota", "Mississippi", "Missouri", "Montana", "Nebraska", "Nevada", "New Hampshire", "New Jersey", "New Mexico", "New York", "North Carolina", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Puerto Rico", "Rhode Island", "South Carolina", "South Dakota", "Tennessee", "Texas", "Utah", "Vermont", "Virginia", "Washington", "West Virginia", "Wisconsin", "Wyoming" ], label: 'State:' %>
  <%= f.input :zipcode, label: 'Zipcode:' %>
  <%= f.input :country, priority: [ "US" ], collection: [ "Canada", "Ireland", "India", "US"], label: 'Country:' %>
  <%= f.input :suite, label: 'Suite:' %>
  <%= f.input :column, label: 'Column:' %>
  <%= f.input :assistant, label: 'Assistant:' %>

  <div class="form-actions">
    <%= f.button :submit, :class => 'btn-primary' %>
    <%= link_to t('.cancel', :default => t("helpers.links.cancel")),
                people_path, :class => 'btn' %>
  </div>
<% end %>

下面是我在development.log中看到的内容

Started PATCH "/people/3" for 127.0.0.1 at 2014-02-13 14:47:12 -0600
Processing by PeopleController#update as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"et3p2hPLTKvVh7aAkD9OCq8IHJe9kZ52L/WFiNmity0=", "person"=>{"crop_x"=>"200", "crop_y"=>"0", "crop_w"=>"400", "crop_h"=>"400"}, "commit"=>"Crop Photo", "id"=>"3"}
  [1m[36mPerson Load (1.5ms)[0m  [1mSELECT "people".* FROM "people" WHERE "people"."id" = $1 LIMIT 1[0m  [["id", "3"]]
  [1m[35m (1.3ms)[0m  BEGIN
  [1m[36m (0.2ms)[0m  [1mROLLBACK[0m
Completed 500 Internal Server Error in 1430ms

NoMethodError (undefined method `body' for nil:NilClass):
  app/models/person.rb:11:in `crop_photo'
  app/controllers/people_controller.rb:49:in `update'

这是我的完整跟踪：

carrierwave (0.9.0) lib/carrierwave/storage/fog.rb:227:in `read'
carrierwave (0.9.0) lib/carrierwave/uploader/cache.rb:77:in `sanitized_file'
carrierwave (0.9.0) lib/carrierwave/uploader/cache.rb:116:in `cache!'
carrierwave (0.9.0) lib/carrierwave/uploader/versions.rb:225:in `recreate_versions!'
app/models/person.rb:11:in `crop_photo'
activesupport (4.0.2) lib/active_support/callbacks.rb:386:in `_run__335866053033251740__update__callbacks'
activesupport (4.0.2) lib/active_support/callbacks.rb:80:in `run_callbacks'
activerecord (4.0.2) lib/active_record/callbacks.rb:310:in `update_record'
activerecord (4.0.2) lib/active_record/timestamp.rb:70:in `update_record'
activerecord (4.0.2) lib/active_record/persistence.rb:477:in `create_or_update'
activerecord (4.0.2) lib/active_record/callbacks.rb:302:in `block in create_or_update'
activesupport (4.0.2) lib/active_support/callbacks.rb:383:in `_run__335866053033251740__save__callbacks'
activesupport (4.0.2) lib/active_support/callbacks.rb:80:in `run_callbacks'
activerecord (4.0.2) lib/active_record/callbacks.rb:302:in `create_or_update'
activerecord (4.0.2) lib/active_record/persistence.rb:106:in `save'
activerecord (4.0.2) lib/active_record/validations.rb:51:in `save'
activerecord (4.0.2) lib/active_record/attribute_methods/dirty.rb:32:in `save'
activerecord (4.0.2) lib/active_record/transactions.rb:270:in `block (2 levels) in save'
activerecord (4.0.2) lib/active_record/transactions.rb:326:in `block in with_transaction_returning_status'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/database_statements.rb:200:in `transaction'
activerecord (4.0.2) lib/active_record/transactions.rb:209:in `transaction'
activerecord (4.0.2) lib/active_record/transactions.rb:323:in `with_transaction_returning_status'
activerecord (4.0.2) lib/active_record/transactions.rb:270:in `block in save'
activerecord (4.0.2) lib/active_record/transactions.rb:281:in `rollback_active_record_state!'
activerecord (4.0.2) lib/active_record/transactions.rb:269:in `save'
activerecord (4.0.2) lib/active_record/persistence.rb:230:in `block in update'
activerecord (4.0.2) lib/active_record/transactions.rb:326:in `block in with_transaction_returning_status'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/database_statements.rb:202:in `block in transaction'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/database_statements.rb:210:in `within_new_transaction'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/database_statements.rb:202:in `transaction'
activerecord (4.0.2) lib/active_record/transactions.rb:209:in `transaction'
activerecord (4.0.2) lib/active_record/transactions.rb:323:in `with_transaction_returning_status'
activerecord (4.0.2) lib/active_record/persistence.rb:228:in `update'
app/controllers/people_controller.rb:49:in `update'
actionpack (4.0.2) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (4.0.2) lib/abstract_controller/base.rb:189:in `process_action'
actionpack (4.0.2) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.0.2) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (4.0.2) lib/active_support/callbacks.rb:413:in `_run__922881453698794513__process_action__callbacks'
activesupport (4.0.2) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.2) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (4.0.2) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.0.2) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.0.2) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.0.2) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.0.2) lib/active_support/notifications.rb:159:in `instrument'
actionpack (4.0.2) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.0.2) lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
activerecord (4.0.2) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.0.2) lib/abstract_controller/base.rb:136:in `process'
actionpack (4.0.2) lib/abstract_controller/rendering.rb:44:in `process'
actionpack (4.0.2) lib/action_controller/metal.rb:195:in `dispatch'
actionpack (4.0.2) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.0.2) lib/action_controller/metal.rb:231:in `block in action'
actionpack (4.0.2) lib/action_dispatch/routing/route_set.rb:80:in `call'
actionpack (4.0.2) lib/action_dispatch/routing/route_set.rb:80:in `dispatch'
actionpack (4.0.2) lib/action_dispatch/routing/route_set.rb:48:in `call'
actionpack (4.0.2) lib/action_dispatch/journey/router.rb:71:in `block in call'
actionpack (4.0.2) lib/action_dispatch/journey/router.rb:59:in `each'
actionpack (4.0.2) lib/action_dispatch/journey/router.rb:59:in `call'
actionpack (4.0.2) lib/action_dispatch/routing/route_set.rb:680:in `call'
rack (1.5.2) lib/rack/etag.rb:23:in `call'
rack (1.5.2) lib/rack/conditionalget.rb:35:in `call'
rack (1.5.2) lib/rack/head.rb:11:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/flash.rb:241:in `call'
rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.5.2) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/cookies.rb:486:in `call'
activerecord (4.0.2) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call'
activerecord (4.0.2) lib/active_record/migration.rb:369:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.0.2) lib/active_support/callbacks.rb:373:in `_run__3121532127090690729__call__callbacks'
activesupport (4.0.2) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.2) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/reloader.rb:64:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.2) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.2) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.0.2) lib/active_support/tagged_logging.rb:67:in `block in tagged'
activesupport (4.0.2) lib/active_support/tagged_logging.rb:25:in `tagged'
activesupport (4.0.2) lib/active_support/tagged_logging.rb:67:in `tagged'
railties (4.0.2) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.2) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/static.rb:64:in `call'
rack (1.5.2) lib/rack/sendfile.rb:112:in `call'
railties (4.0.2) lib/rails/engine.rb:511:in `call'
railties (4.0.2) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
/Users/scottsipiora/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
/Users/scottsipiora/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
/Users/scottsipiora/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'

我能做些什么来解决这个问题呢？

谢谢

Answer 1

触发异常的实际代码在Carrierwave repository中。回溯到where，它实际上是被调用的，它告诉我们它正试图缓存一个由于某种原因而不存在的文件。调试的下一步是实际确保您尝试重新裁剪的文件存在。我在想，因为你是在after_update钩子中这样做的，所以你的文件可能不会以你需要的状态存在。