使用回形针将对象与S3上的现有文件相关联

Question

I have a file already on S3 that I'd like to associate to a pre-existing instance of the Asset model.

Here's the model:

class Asset < ActiveRecord::Base
  attr_accessible(:attachment_content_type, :attachment_file_name,
                 :attachment_file_size, :attachment_updated_at, :attachment)

  has_attached_file :attachment, {
    storage: :s3,
    s3_credentials: {
      access_key_id: ENV['AWS_ACCESS_KEY_ID'],
      secret_access_key: ENV['AWS_SECRET_ACCESS_KEY'],
    },
    convert_options: { all: '-auto-orient' },
    url: ':s3_alias_url',
    s3_host_alias: ENV['S3_HOST_ALIAS'],
    path: ":class/:attachment/:id_partition/:style/:filename",
    bucket: ENV['S3_BUCKET_NAME'],
    s3_protocol: 'https'
  }
end

Let's say the path is assets/attachments/000/111/file.png , and the Asset instance I want to associate with the file is asset . Referring at the source , I've tried:

options = {
    storage: :s3,
    s3_credentials: {
      access_key_id: ENV['AWS_ACCESS_KEY_ID'],
      secret_access_key: ENV['AWS_SECRET_ACCESS_KEY'],
    },
    convert_options: { all: '-auto-orient' },
    url: ':s3_alias_url',
    s3_host_alias: ENV['S3_HOST_ALIAS'],
    path: "assets/attachments/000/111/file.png",
    bucket: ENV['S3_BUCKET_NAME'],
    s3_protocol: 'https'
  }
# The above is identical to the options given in the model, except for the path

Paperclip::Attachment.new("file.png", asset, options).save

As far as I can tell, this did not affect asset in any way. I cannot set asset.attachment.path manually.

Other questions on SO do not seem to address this specifically. " paperclip images not saving in the path i've set up ", " Paperclip and Amazon S3 how to do paths? ", and so on involve setting up the model, which is already working fine.

Anyone have any insight to offer?

Answer 1

As far as I can tell, I do need to turn the S3 object into a File , as suggested by @oregontrail256. I used the Fog gem to do this.

s3 = Fog::Storage.new(
        :provider => 'AWS',
        :aws_access_key_id => ENV['AWS_ACCESS_KEY_ID'],
        :aws_secret_access_key => ENV['AWS_SECRET_ACCESS_KEY']
      )

directory = s3.directories.get(ENV['S3_BUCKET_NAME'])
fog_file = directory.files.get(path)

file = File.open("temp", "wb")
file.write(fog_file.body)
asset.attachment = file
asset.save
file.close

Answer 2

Paperclip attachments have a copy_to_local_file() method that allows you to make a local copy of the attachment. So what about:

file_name = "temp_file"
asset1.attachment.copy_to_local_file(:style, file_name)
file = File.open(file_name)
asset2.attachment = file
file.close
asset2.save!

Even if you destroy asset1, you now have a copy of the attachment saved by asset2 separately. You probably want to do this in a background job if you're doing many of them.

Credit to this answer too: How to set a file upload programmatically using Paperclip