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所以我有一个网站已经在生产中，它使用存储在亚马逊 s3 上的图像的carrierwave gem。我的上传者使用该store_dir方法指定特定结构以放入处理后的图像。

好吧，现在在我的开发环境中，我添加了carrierwave_direct gem 以开始直接上传到S3。问题是这个 gem 完全覆盖了我的上传器中的 store_dir 和文件名默认值。我无法实时推送我完全正常工作的上传器，因为我所有的旧图片链接都会被破坏。

据我了解，CWdirect gem 会将原始图像文件上传到 S3 上的“临时”目录，然后 S3 会响应并为您提供一个key变量，以便您可以获取该文件并按照您认为合适的方式处理它。那么，我应该在carrierwave中使用一个完全独立的图像上传器类来处理图像并将它们放在正确的文件夹中吗？这意味着我将有一个专门用于carrierwave_direct 的上传器，可以上传这个gem 似乎想要上传到的任何地方；我将使用另一个链接到我的真实模型的 uploader.rb 类来保持我当前的 store_dir 和文件名结构？

无论如何，我的基本问题是，如果我已经在生产中运行 CW，并且图像在特定文件夹结构中，我该如何使用 CarrierWave_Direct gem？

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1 回答 1

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好的，所以我确实想出了如何做到这一点，我将在下面解释。我的直觉是使用两个不同的 CarrierWave 上传器类是正确的——一个类专门用于上传到 S3（使用 CarrierWave_Direct gem），第二个类仅用于图像处理（我已经在生产中使用的类）。我会尝试在下面发布相关代码，但如果有人有问题请告诉我。我不确定为什么我没有看到其他人使用这样的单独类，但它似乎对我有用。

我的图片上传器类app\uploaders\image_uploader.rb使用carrierwave_direct gem：

class ImageUploader < CarrierWave::Uploader::Base
  include CarrierWaveDirect::Uploader

  include ActiveModel::Conversion
  extend ActiveModel::Naming

  include CarrierWave::MimeTypes
  process :set_content_type

  # 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

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

  # Override the directory where uploaded files will be stored.
  # CarrierWaveDirect::Uploader puts raw uploaded files in this directory on S3 as a first step
  def store_dir
    "unprocessed_uploads"
  end
end

**注意在这个类中没有进行任何处理

我的图像处理类app\uploaders\image_processor.rb（生产中已经存在的）：

class ImageProcessor < CarrierWave::Uploader::Base

  # Include RMagick or MiniMagick support:
  # include CarrierWave::RMagick
  include CarrierWave::MiniMagick
  include CarrierWave::MimeTypes
  process :set_content_type

  # 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 :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}"
    # "uploads/#{model.class.to_s.underscore}/path/#{model.id}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  def default_url
    "logos/" + [version_name, "default.png"].compact.join('_')
  end

  # Process files fetched from S3 after they are uploaded:

  def make_thumbnail(width, height)
    # uses MiniMagick classes to get a square, centered thumbnail image
    manipulate! do |img|
      if img[:width] < img[:height]
        remove = ((img[:height] - img[:width])/2).round
        img.shave("0x#{remove}")
      elsif img[:width] > img[:height]
        remove = ((img[:width] - img[:height])/2).round
        img.shave("#{remove}x0")
      end

      img.resize("#{width}x#{height}")
      img
    end        
  end


  # Create different versions of your uploaded files:
  # the process statement below isn't defined within a version block on purpose--this means the ORIGINAL uploaded photo is constrained to 1050 pics
  process :resize_to_limit => [1050, 1050]
  process :quality => 85 # this reduces filesize greatly and saves space

  version :thumb do
    process :make_thumbnail => [100, 100]
    process :quality => 85 # this reduces filesize greatly and saves space
  end

  version :big_thumb do
    process :make_thumbnail => [350, 350]
    process :quality => 85 # this reduces filesize greatly and saves space
  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
    if original_filename
      if model && model.read_attribute(:image).present?
        model.read_attribute(:image)
      else
        "#{secure_token}.#{file.extension}"
      end
    end
  end

protected
  def secure_token
    var = :"@#{mounted_as}_secure_token"
    model.instance_variable_get(var) or model.instance_variable_set(var, SecureRandom.uuid)
  end

end

我的照片模型（总结）：

class Photo < ActiveRecord::Base
  mount_uploader :image, ImageProcessor

  def save_and_process_image(options = {})
    s3_unprocessed_image_url = self.image.asset_host + '/' + self.key
      # this next line downloads the image from S3
      # and this save line below will process the image and reupload to S3 according to ImageProcessor settings
      self.remote_image_url = s3_unprocessed_image_url
      save
  end

end

我也有可用的照片控制器和查看代码，如果你想要它让我知道。基本上，我使用 ImageUploader 类将初始上传到 S3 到一个名为 unprocessed_uploads 的文件夹。然后 S3 用key我传递给 ImageProcessor 类的 URL 中的一个字段进行响应——它附加到照片并处理缩略图和其他图像，然后将它们重新上传到我在 S3 上的上传文件夹。

这种分离意味着我在添加carrierwave_direct gem 时不需要更改我在S3 上的当前文件夹结构。希望这对其他人有帮助。如果您需要更多代码，请告诉我，我有点厌倦了打字:)

更新——添加更多代码：

照片控制器：

class PhotosController < ApplicationController

  def index
    @photos = @photos.sort_by(&:created_at)

    @uploader = ImageUploader.new
    @uploader.success_action_redirect = new_tank_photo_url(@tank)

    respond_to do |format|
      format.html # index.html.erb
      format.json { render json: @photos }
    end
  end

  def create
    respond_to do |format|

      if @photo.save_and_process_image
        format.html { redirect_to tank_photos_path(@tank), notice: 'Photo uploaded successfully and is being processed...' }
        format.json { render json: @photo, status: :created, location: @photo }
      else
        format.html { render :new }
        format.json { render json: @photo.errors, status: :unprocessable_entity }
      end
    end
  end

照片索引视图，带有上传按钮的表单：

    <%= direct_upload_form_for @uploader, :html => {:class => "form-inline"} do |f| %>
        <%= f.file_field :image %>
        <%= f.submit "Upload", :class => "btn btn-primary btn-medium" %>
    <% end %>

因此，添加了上述视图/控制器代码后，这里是所采取步骤的摘要。ImageUploader请注意类和类之间的区别ImageProcessor：

  1. 在我的照片控制器中，我创建了属于 ImageUploader 类的 @uploader 变量——这意味着在使用 @uploader 的索引/视图表单中提交的图像会将图像上传到“临时”文件夹——因为它使用 ImageUploader 类然后在上传此图像时（尚未）不进行任何处理。
  2. 当用户单击表单上的“上传”按钮时，会调用照片>>创建操作。此操作调用@photo.save_and_process_image - 查看模型以查看此方法实际上从 S3 的“临时”文件夹中获取最近上传的图像，对其进行处理，然后将处理后的图像重新上传到其最终目的地。这一切都是可能的，因为我的 Photo 模型链接到ImageProcessor类，该类进行处理/上传。它没有链接到单独的 ImageUploader 类。

希望这有助于解释我正在发生的事情

于 2013-02-12T22:13:18.493 回答