ruby-on-rails-3 - CarrierWave 显示 image_url 错误

Question

我正在使用 CarrierWave 将图像上传到我的服务器。但是，当我用 image_url 引用它们时，我得到了 nil:NilClass 的 NoMethodError for image_url。

app/assets/views/albums/index.html.erb

<% @albums.each do |album| %>
....
<div>
    <%= image_tag @album.image_url.to_s %>
</div>
<%end%>

app/config/routes.rb

namespace :admin do
    root :to => "dashboard#index"
    resources :dashboard
    resources :albums do
        resources :images
end
    get "admin/album"

app/assets/views/albums/new.html.erb

<div>
    <%= f.file_field :image %>
</div>

app/assets/models/Image.rb

class Image < ActiveRecord::Base
    attr_accessible :album_id, :title, :image
    belongs_to :album
    mount_uploader :image, ImageUploader
end

image_uploader.rb

 # encoding: utf-8

class ImageUploader < CarrierWave::Uploader::Base

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

  # Include the Sprockets helpers for Rails 3.1+ asset pipeline compatibility:
  # include Sprockets::Helpers::RailsHelper
  # include Sprockets::Helpers::IsolatedHelper

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

  # 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:
  #   # 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 :thumb do
  #   process :scale => [50, 50]
  # 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

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  # def filename
  #   "something.jpg" if original_filename
  # end

end

我已经尝试了几个小时来修复这个错误。我可以通过将 image_tag 路径设置为 image_url(@album) 来消除错误，但这不会显示图像。

更多信息

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app/views/admin/albums/index.html.erb:3:in `each'
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script/rails:6:in `require'
script/rails:6

app/assets/views/albums/index.html.erb

 <h1>These are the albums</h1>
 <% @albums.each do |album| %>
 <div class="item" style="background: #e4e4e4; border: 2px solid #c9c9c9; padding:1.5em  0 1.5em 0; width:17em; font-family: 'Signika Negative';">
 <div class="title" style="background: #d3d3d3; display: inline-block; padding:1.5em 0      1.5em 1em; width: 12em;">
<strong>Title</strong> </br>
<%= album.title %></div>
 </br>
 <div class="description" style="background: #f9f9f9; display: inline-block; padding: 1.5em 0 1.5em 1em; width: 12em;">
<strong>Description</strong> </br>
<%= album.description %>
 </div>
</br>
<div>
<%= image_tag album.image.image_url.to_s %>
</div>
<div>

</div>
<%= link_to "Delete", admin_album_path(album), :method => :delete, :style => "margin: 1em 0 0 1em; display: block;" %>
</br>
</div>
<% end %>
<%=link_to "New Album", :controller => "albums", :action => "new" %>
<%=link_to "Manage Pictures"%>

Answer 1

你似乎与相册和图像有关系。假设相册有_许多您需要的图片:

@albums.each do |album|
  album.images.each{|image| image.image_url }
end