Change ActiveStorage DirectDisk service configuration at runtime

Question

I am using Rails 5.2 and ActiveStorage 5.2.3 and DirectDiskService.

In order to have user uploads grouped nicely in directories and in order to be able to use CDNs as I please (eg CloudFlare or CloudFront or any other), I am trying to set up a method in ApplicationController that sets the (local) path for uploads, something like:

class ApplicationController < ActionController::Base
  before_action :set_uploads_path

  # ...

private
  def set_upload_paths
     # this doesn't work
     ActiveStorage::Service::DirectDiskService.set_root p: "users/#{current_user.username}"
     # ... expecting the new root to become "public/users/yaddayadda"
  end
end

In config/initializers/active_storage.rb I have:

module SetDirectDiskServiceRoot
    def set_root(p:)
        @root = Rails.root.join("public", p)
        @public_root = p
        @public_root.prepend('/') unless @public_root.starts_with?('/')
    end
end

ActiveStorage::Service::DirectDiskService.module_eval { attr_writer :root }
ActiveStorage::Service::DirectDiskService.class_eval { include SetDirectDiskServiceRoot }

It does let me set the root on a new instance of the service but not on the one the Rails application is using.

What am I doing wrong? Or how do I get this done?

Answer 1

Here's a dirty hack that helps you keep your local (disk) uploads grouped nice under public/websites/domain_name/uploads.

Step 1) install ActiveStorage DirectDisk service from here: https://github.com/sandrew/activestorage_direct_disk

Step 2) in app/models/active_storage/current.rb

class ActiveStorage::Current < ActiveSupport::CurrentAttributes #:nodoc:
  attribute :host
  attribute :domain_name
end

Step 3) lib/set_direct_disk_service_path.rb

module SetCurrentDomainName
    def set_domain_name(d)
        self.domain_name = d
    end
end

ActiveStorage::Current.class_eval { include SetCurrentDomainName }

module SetDirectDiskServiceRoot
    def initialize(p:, public: false, **options)
        @root = Rails.root.join("public", p)
        @public_root = p
        @public_root.prepend('/') unless @public_root.starts_with?('/')
        puts options
    end

    def current_domain_name
        ActiveStorage::Current.domain_name
    end

    def folder_for(key)
        # original: File.join root, folder_for(key), key
        p = [ current_domain_name, "uploads", "all", key ]
        blob = ActiveStorage::Blob.find_by(key: key)
        if blob
            att = blob.attachments.first
            if att
                rec = att.record
                if rec
                    p = [ current_domain_name, "uploads", rec.class.name.split("::").last.downcase, rec.id.to_s, att.name, key ]
                end
            end
        end
        return File.join p
    end
end

ActiveStorage::Service::DirectDiskService.module_eval { attr_writer :root }
ActiveStorage::Service::DirectDiskService.class_eval { include SetDirectDiskServiceRoot }

Step 4) in config/initializers/active_storage.rb

require Rails.root.join("lib", "set_direct_disk_service_path.rb")

Step 5) in app/controllers/application_controller.rb

before_action :set_active_storage_domain_name

# ...
def set_active_storage_domain_name
    ActiveStorage::Current.domain_name = current_website.domain_name # or request.host
end

Step 6) in config/storage.yml

development:
  service: DirectDisk
  root: 'websites_development'

production:
  service: DirectDisk
  root: 'websites'

Disadvantages:

While ActiveRecord technically "works", it's missing some very important features that make it unusable for most people, so eventually the developer(s) will listen and adjust; at that time you may need to revisit this code AND all of your uploads.

The service attempts to "guess" the class name a blob is attached to since AS doesn't pass that, so it runs extra 2-3 queries against your database. If this bothers you just remove that bit and let it all go under websites/domain_name/uploads/all/

In some cases (eg variants, or a new record with action_text column) it can't figure out the attachment record and its class name, so it will upload under websites/domain/uploads/all/...