[SOLVED] How to resolve url for static asset in S3 with DefaultUrl plugin

How to resolve url for static asset in S3 with DefaultUrl plugin

i'm having trouble finding the correct way to generate a S3 URL for a public static asset through the default_url plugin in Shrine. The asset is the users avatar, which can be nil, so the idea was to use the plugin default_url to get the empty avatar image. Following the docs I've arrived to this:

class AvatarUploader < Shrine
  plugin :default_url

  Attacher.default_url do |options|
    '/user_avatar.png'
  end
end

But this generates a relative URL. I've also tried using the :host option as pointed out here. But it only works if I hardcode the complete endpoing URL, which is no good.

plugin :default_url, host: "https://my-public-bucket.s3.amazonaws.com"

attacher.url #=> "https://my-public-bucket.s3.amazonaws.com/user_avatar.png"

Other option would be, to set the bucket name in an environment variable:

plugin :default_url, host: "https://#{ENV["S3BUCKET_PUBLIC"]}.s3.amazonaws.com"

but I think is not good either.

Is there a way to programmatically create the full URL directly from Shrine, using its existing configs?

Solution

To programmatically create the URL I needed to call Shrine#uploaded_file with an options hash:

class AvatarUploader < Shrine
  plugin :default_url
  
  Attacher.default_url do |options|
    data = { "id" => "user_avatar.png", "storage" => :bucket_name_from_config }
    shrine_class.uploaded_file(data).url
  end
end