ruby-on-rails - 如何 DRY 我在 5 个模型中编写的 has_attached_file

Question

这是我在 5 种不同模型(相同代码)中编写的代码。

has_attached_file :image,
    s3_region: 'ap-northeast-1',
    storage: :s3,
    s3_protocol: :https,
    s3_credentials:  "#{Rails.root}/config/amazon_s3.yml",
    url: ':s3_domain_url',
    path:  '/images/:id/:filename',
    s3_host_alias: 'https://s3-ap-northeast-1.amazonaws.com/'

有什么方法可以将它晾干，以便我只将它放在一个地方并在不同的模型中使用它？

Answer 1

当然，您可以使用 concenrs .

# models/concenrs/attachable.rb
module Attachable
  extend ActiveSupport::Concern

  included do
    has_attached_file :image,
      s3_region: 'ap-northeast-1',
      storage: :s3,
      s3_protocol: :https,
      s3_credentials:  "#{Rails.root}/config/amazon_s3.yml",
      url: ':s3_domain_url',
      path:  '/images/:id/:filename',
      s3_host_alias: 'https://s3-ap-northeast-1.amazonaws.com/'
  end
end

在模型中:

class User < ApplicationRecord
  include Attachable
end

附言Ilya 的谨慎评论的意思是，虽然在模型中保留 S3 存储设置是一个可行的解决方案，但您最好将这些设置放入配置文件中。有关一些示例，请参阅 official Paperclip-with-Amazon-S3 guide (还有关于 Paperclip::Storage::S3 类的其他文章和文档的链接)。

一个选项是:

# config/secrets.yml
defaults: &defaults
  amazon:
    s3_bucket_name: 's3_bucket_name'
    aws_access_key_id: 'access_key_id'
    aws_secret_access_key: 'aws_secret_access_key'
    aws_region: 'aws_region'

# config/environments/production.rb
config.paperclip_defaults = {
  storage: :s3,
  s3_credentials: {
    bucket: Rails.application.secrets.amazon['s3_bucket_name'],
    access_key_id: Rails.application.secrets.amazon['aws_access_key_id'],
    secret_access_key: Rails.application.secrets.amazon['aws_secret_access_key'],
    s3_region: Rails.application.secrets.amazon['aws_regio'],
  }
}