Graphiti ActiveStorage attachment

application_resource.rb

# app/resources/application_resource.rb

# ApplicationResource is similar to ApplicationRecord - a base class that
# holds configuration/methods for subclasses.
# All Resources should inherit from ApplicationResource.
class ApplicationResource < Graphiti::Resource
  # Use the ActiveRecord Adapter for all subclasses.
  # Subclasses can still override this default.
  self.abstract_class = true
  self.adapter = Graphiti::Adapters::ActiveRecord
  self.base_url = Rails.application.routes.default_url_options[:host]
  self.endpoint_namespace = '/api/v1'

  around_persistence :handle_attachment_attributes

  protected

  # Extract attachment from attributes before saving model
  # Attach attachments after save
  def handle_attachment_attributes(attrs)
    attachments_params = extract_attachments_params(attrs)
    model = yield
    save_attachments(model, attachments_params)
  end

  #@return [Hash] Attributes definitions matching type "attachment"
  def attachment_attributes
    self.attributes.select{|_name, opts| opts[:type].to_s == "attachment"}
  end

  #@return [Hash] Extracted attachment params
  def extract_attachments_params(attrs)
    Hash.new.tap do |attachments_params|
      attachment_attributes.each do |name, _opts|
        attachments_params[name] = attrs.delete(name.to_sym)
      end
    end
  end

  # Add attachments to saved model
  def save_attachments(model, attachments_params)
    attachments_params.each do |name, params|
      # ActiveStorage attachment name is inferred from the param name
      # but can also be overridden with option `:attached_as`
      type = attachment_attributes[name].fetch(:attached_as){name}
      attach(model, type, params)
    end
  end

  # Attach a single attachment
  def attach(record, type, params)
    file = tempfile_for(params[:data])
    record.send(type).attach(io: file, **params.slice(:filename, :content_type))
  end

  def tempfile_for(data)
    file = Tempfile.new('temp')
    file.binmode
    file.write(Base64.decode64(data))
    file.close
    file.open
    file
  end
end

attachment.rb

# app/models/types/attachment.rb

module Types
  module Attachment

    # validate attachment format
    # Use Types::Hash.strict to avoid sending unwanted params to ActiveStorage
    WriteAttachment = Types::Hash.schema(
      data: Types::Strict::String,
      filename: Types::Strict::String,
      content_type?: Types::Strict::String
    ).with_key_transform(&:to_sym).strict

    # Serialize to Hash
    ReadAttachment = Types::Nominal::Hash.constructor do |attachment|
      if attachment.attached?
        {
          url:  Rails.application.routes.url_helpers.rails_blob_path(attachment, only_path: true),
          filename: attachment.filename,
          content_type: attachment.content_type
        }
      else
        nil
      end
    end
  end
end

Example - GET response.json

{
    "data": {
        "id": "2235",
        "type": "places",
        "attributes": {
            "name": "Test name",
            "coordinates": {
                "lon": 5.11135,
                "lat": 45.41
            },
            "image": {
                "url": "/rails/active_storage/blobs/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaHBBcmNDIiwiZXhwIjpudWxsLCJwdXIiOiJibG9iX2lkIn19--6ba858d6903afb5290a959befe3fda6481c6332b/present.png",
                "filename": "image.png",
                "content_type": "image/png"
            }
        }
    },
    "meta": {}
}

Example - POST Request.json

{
	"data":{
		"type": "places",
		"attributes":{
			"name": "Test name",
			"coordinates": {
				"lon": 5.11135,
				"lat": 45.41
			},
			"image": {
				"filename": "image.png",
				"data": "iVBORw0KGgoAAAANSUh...truncated base64...5QzFVEtFUveAAAAAElFTkSuQmCC"
			}
		}
	}	
}

graphiti_types.rb

# config/initializers/graphiti_types.rb

Graphiti::Types[:attachment] = {
  params: Types::Attachment::WriteAttachment,
  read: Types::Attachment::ReadAttachment,
  write: Types::Attachment::WriteAttachment,
  kind: 'record',
  canonical_name: :attachment,
  description: 'Active Storage file attached to the resource model'
}

place.rb

# app/models/place.rb:7

class Place < ApplicationRecord

  validates :name, presence: true
  validates :coordinates, presence: true

  has_one_attached :photo

end

place_resource.rb

# app/resources/place_resource.rb

class PlaceResource < ApplicationResource

  attribute :name, :string
  attribute :coordinates, :geo_point

  attribute :image, :attachment, attached_as: "photo"

  def base_scope
    Place.with_attached_photo
  end
end

Thanks! Any suggestions/plan to update it for has_many_attached?