Carrierwave宝石.如何在重新创建后重命名上传的图像版本？

Question

我有类似RailsCasts中描述的模型:

应用程序/模型/ resident.rb:

class Resident < ActiveRecord::Base
  include PhotoConcern
end

应用程序/模型/ employee.rb:

class Employee < ActiveRecord::Base
  include PhotoConcern
end

应用程序/模型/忧虑/ photo_concern.rb:

module PhotoConcern
  extend ActiveSupport::Concern

  included do
    mount_uploader :photo, PhotoUploader

    attr_accessor :photo_crop_x, :photo_crop_y, :photo_crop_w, :photo_crop_h

    after_save :crop_photo

    def crop_photo
      photo.recreate_versions! if photo_crop_x.present?
    end
  end
end

应用程序/上传/ photo_uploader.rb:

class PhotoUploader < CarrierWave::Uploader::Base
  include CarrierWave::MiniMagick

  storage :file

  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  version :cropped do
    process :crop
  end

  version :thumb, from_version: :cropped do
    process resize_to_fill: [100, 100]
  end

  version :avatar, from_version: :cropped do
    process resize_to_fill: [200, 200]
  end

  def crop
    return if model.photo_crop_x.blank?

    resize_to_limit(500, nil)
    resize_to_fit(500, nil)

    manipulate! do |img|
      size = model.photo_crop_w << 'x' << model.photo_crop_h
      offset = '+' << model.photo_crop_x << '+' << model.photo_crop_y

      img.crop("#{size}#{offset}")
      img
    end
  end
end

应用程序/视图/员工/ show.slim

= image_tag (@employee.photo.present? ? @employee.photo.url(:avatar) : "client_#{@employee.sex}.png"), class: 'img-circle img-responsive'

我想在裁剪后重命名版本文件,这样我的用户就不会为缓存而烦恼.它在CarrierWave wiki中描述了如何重命名文件,但也写了 "为了保存新生成的文件名,你必须在recreate_versions之后调用模型上的save!".

如何重命名版本文件？我无法再次调用save!我的员工after_save,因为有更多的钩子不应该被调用两次.此外,PhotoConcern包含在另一个类中.

相关维基文章:

• 如何:为所有版本化文件创建随机和唯一的文件名
• 如何:自定义您的版本文件名
• 如何:在文件名中使用时间戳

Answer 1

为了保存新生成的文件名,您必须调用save!在recreate_versions之后的模型!

所以我相信你怀疑的答案包含在Carrierwave ruby​​documentation中

recreate_versions!(*versions) ? Object

重新创建版本并重新处理它们.如果它们的参数以某种方式发生了变化,这可用于重新创建版本.

*versions如果不省略它们,则此方法将存储,否则cached file将存储.

# File 'lib/carrierwave/uploader/versions.rb', line 216

def recreate_versions!(*versions)
  # Some files could possibly not be stored on the local disk. This
  # doesn't play nicely with processing. Make sure that we're only
  # processing a cached file
  #
  # The call to store! will trigger the necessary callbacks to both
  # process this version and all sub-versions
  if versions.any?
    file = sanitized_file if !cached?
    # the file will be stored
    store_versions!(file, versions)
  else
    cache! if !cached?
    # If new_file is omitted, a previously cached file will be stored.
    store!
  end

怎么store!办？

这是rubydoc页面store!

store!(new_file = nil) ? Object

通过将文件传递给此Uploader的存储引擎来存储文件.如果省略new_file,则将存储先前缓存的文件

此方法包含在您的中class PhotoUploader < CarrierWave::Uploader::Base,它用于with_callbacks使用回调存储您的文件:store.回调会触发此方法.

# File 'lib/carrierwave/uploader/store.rb', line 53

def store!(new_file=nil)
  cache!(new_file) if new_file && ((@cache_id != parent_cache_id) || @cache_id.nil?)
  if !cache_only and @file and @cache_id
    with_callbacks(:store, new_file) do
      new_file = storage.store!(@file)
      if delete_tmp_file_after_storage
        @file.delete unless move_to_store
        cache_storage.delete_dir!(cache_path(nil))
      end
      @file = new_file
      @cache_id = nil
    end
  end
end

是什么store_versions!方法呢？

def store_versions!(new_file, versions=nil)
  if versions
    active = Hash[active_versions]
    versions.each { |v| active[v].try(:store!, new_file) } unless active.empty?
  else
    active_versions.each { |name, v| v.store!(new_file) }
  end
end

什么是Carrierwave回调以及如何使用它们？

 after :store, :store_versions!

关于SO的这个问题解释了并且wiki解释了回调如何工作,通过after :store, :my_method在version :low do块内部执行,您将my_method仅在after :store回调时执行(仅适用于该版本).

该:store回调对应的执行store!.

什么@filename属性？如何recreate_versions!编码文件名？

@filename与方法定义filename在lib/carrierwave/uploader/store.rb

##
# Override this in your Uploader to change the filename.
#
# Be careful using record ids as filenames. If the filename is stored in the database
# the record id will be nil when the filename is set. Don't use record ids unless you
# understand this limitation.
#
# Do not use the version_name in the filename, as it will prevent versions from being
# loaded correctly.
#
# === Returns
#
# [String] a filename
#
def filename
  @filename
end

来自carrierwave的指南建议在def filename重新创建版本时使用重新创建唯一的文件名recreate_version!.

此方法不保存到数据库,保存到数据库,您需要save!在appropriata Carrierwave回调上调用,而不会破坏您的CarrierwaveGEM

我没有这个问题的解决方案,但没有相关的文档,我们应该开始构建它.