Shrine Ruby on Rails无服务器图像处理程序，后台作业

Question

我正在使用S3 multipart upload在我的Ruby on Rails项目中使用神社宝石来处理文件。我想使用派生插件指向一个AWS Lamdba无服务器图像处理程序作为我的派生remote_url，并在后台工作中处理这些派生。只有一个问题，我已经让它工作了：

上传文件后，该记录立即与神社cache存储url一起保存。一旦后台作业完成处理并创建了派生，promote作业就会使用store端点更新attachment_url。

因此，我想要做的是首先将原始的URL提升到store存储桶(这样default_url将指向store存储桶，而不是缓存)，然后再处理派生的URL。然而，我不太明白如何做到这一点。下面是我的神社初始化器和上传器。

# config/initializers/shrine.rb

require 'shrine'
require 'shrine/storage/s3'
# require "shrine/storage/file_system"

s3_options = Rails.application.credentials.s3

Shrine.storages = {
  cache: Shrine::Storage::S3.new(prefix: 'cache', public: true, **s3_options),
  store: Shrine::Storage::S3.new(prefix: 'media', public: true, **s3_options),
}

Shrine.plugin :activerecord           # Load Active Record integration
Shrine.plugin :cached_attachment_data # For retaining cached file on form redisplays
Shrine.plugin :determine_mime_type
Shrine.plugin :infer_extension
Shrine.plugin :instrumentation
Shrine.plugin :pretty_location
Shrine.plugin :remote_url, max_size: 40*1024*1024 # ~40mb
Shrine.plugin :restore_cached_data    # Refresh metadata for cached files
Shrine.plugin :type_predicates
Shrine.plugin :uppy_s3_multipart      # Enable S3 multipart upload for Uppy https://github.com/janko/uppy-s3_multipart
Shrine.plugin :url_options, store: { host: Rails.application.credentials.asset_host } if Rails.application.credentials.asset_host.present?

# app/uploaders/file_uploader.rb

class FileUploader < Shrine
  plugin :derivatives
  plugin :default_url
  plugin :backgrounding

  # TODO: images returned by Shrine.remote_url have file extension set as .jpeg, not .jpg, which is annoying
  # TODO: set up URL fallbacks for backgrounded derivatives? https://shrinerb.com/docs/processing#url-fallbacks

  # The Cloudfront URL generated by the serverless image handler
  SERVERLESS_IMAGE_HOST = Rails.application.credentials.image_handler_host
  DEFAULT_EDITS = {
    rotate: 'auto',
    quality: 60,
    progressive: true,
    chromaSubsampling: '4:4:4',
    withoutEnlargement: true,
    sharpen: true
  }

  # Fall back to the original file URL when the derivative
  # https://shrinerb.com/docs/processing#url-fallbacks
  Attacher.default_url do |derivative: nil, **|
    file&.url if derivative
  end

  # Perform derivative transformations inside a background job
  Attacher.promote_block do |**options|
    if file.image?
      # TODO: the initially promoted file URL is saved to the record as the cache URL. We need to
      # promote the original image first, then perform the derivative job.
      # promote
      AttachmentDerivativeJob.perform_later(self.class.name, record.class.name, record.id, name, file_data)
    else
      promote
    end
  end

  # The derivatives plugin allows storing processed files ("derivatives") alongside the main attached file
  # https://shrinerb.com/docs/plugins/derivatives
  Attacher.derivatives do |original|
    def serverless_image_request(edits = {})
      request_path = Base64.strict_encode64({
        bucket: Shrine.storages[:cache].bucket.name,
        key: [Shrine.storages[:cache].prefix, record.attachment.id].reject(&:blank?).join('/'), # The aws object key of the original image in the `store` S3 bucket
        edits: edits
      }.to_json).chomp
      "#{SERVERLESS_IMAGE_HOST}/#{request_path}"
    end

    if file.image?
      process_derivatives(:image, original)
    else
      process_derivatives(:file, original)
    end
  end

  Attacher.derivatives :image do |original|
    {
      thumb: Shrine.remote_url( serverless_image_request({
        resize: {
          width: 200,
          height: 200,
          fit: 'cover'
        }.reverse_merge(DEFAULT_EDITS)
      })),
      small: Shrine.remote_url( serverless_image_request({
        resize: {
          width: 600,
          height: 600,
          fit: 'inside'
        }.reverse_merge(DEFAULT_EDITS)
      })),
      medium: Shrine.remote_url( serverless_image_request({
        resize: {
          width: 1200,
          height: 1200,
          fit: 'inside'
        }.reverse_merge(DEFAULT_EDITS)
      })),
      large: Shrine.remote_url( serverless_image_request({
        resize: {
          width: 2200,
          height: 2200,
          fit: 'inside'
        }.reverse_merge(DEFAULT_EDITS)
      }))
    }
  end

  Attacher.derivatives :file do |original|
    {}
  end
end

Answer 1

一个更新--我能够通过重写Attacher类中的activerecord_after_save方法来配置我的Uploader类，让它按照我想要的方式执行。我不确定这是否是最好的解决方案，但它的行为似乎符合我的预期。

现在，当我上传一系列图像时，它们被直接上传到S3，原始文件被提升为永久神社store。在保存之后的回调中，我触发了AttachmentDerivativeJob，它使用AWS Lambda的默认serverless image handler处理派生数据。

class FileUploader < Shrine
  plugin :derivatives
  plugin :default_url

  # The Cloudfront URL generated by the serverless image handler
  SERVERLESS_IMAGE_HOST = Rails.application.credentials.image_handler_host
  DEFAULT_EDITS = {
    rotate: 'auto',
    quality: 60,
    progressive: true,
    chromaSubsampling: '4:4:4',
    withoutEnlargement: true,
    sharpen: true
  }

  # Active Record - Overriding callbacks
  # https://shrinerb.com/docs/plugins/activerecord#overriding-callbacks
  class Attacher
    private

    def activerecord_after_save
      super

      if file.image? && derivatives.blank?
        AttachmentDerivativeJob.perform_later(self.class.name, self.record.class.name, self.record.id, self.name, self.file_data)
      end
    end
  end

  # Fall back to the original file URL when the derivative
  # https://shrinerb.com/docs/processing#url-fallbacks
  Attacher.default_url do |derivative: nil, **|
    file&.url if derivative
  end

  # The derivatives plugin allows storing processed files ("derivatives") alongside the main attached file
  # https://shrinerb.com/docs/plugins/derivatives
  Attacher.derivatives do |original|
    def serverless_image_request(edits = {})
      request_path = Base64.strict_encode64({
        bucket: Shrine.storages[:store].bucket.name,
        key: [Shrine.storages[:store].prefix, record.attachment.id].reject(&:blank?).join('/'), # The aws object key of the original image in the `store` S3 bucket
        edits: edits
      }.to_json).chomp
      "#{SERVERLESS_IMAGE_HOST}/#{request_path}"
    end

    if file.image?
      process_derivatives(:image, original)
    else
      process_derivatives(:file, original)
    end
  end

  Attacher.derivatives :image do |original|
    {
      thumb: Shrine.remote_url( serverless_image_request({
        resize: {
          width: 200,
          height: 200,
          fit: 'cover'
        }.reverse_merge(DEFAULT_EDITS)
      })),
      small: Shrine.remote_url( serverless_image_request({
        resize: {
          width: 600,
          height: 600,
          fit: 'inside'
        }.reverse_merge(DEFAULT_EDITS)
      })),
      medium: Shrine.remote_url( serverless_image_request({
        resize: {
          width: 1200,
          height: 1200,
          fit: 'inside'
        }.reverse_merge(DEFAULT_EDITS)
      })),
      large: Shrine.remote_url( serverless_image_request({
        resize: {
          width: 2200,
          height: 2200,
          fit: 'inside'
        }.reverse_merge(DEFAULT_EDITS)
      }))
    }
  end

  Attacher.derivatives :file do |original|
    {}
  end
end