如何获取活动存储映像的URL

我想通过API获取带有附加图像的记录列表,作为链接或文件。

我有一个简单的模型:

class Category < ApplicationRecord
  has_one_attached :image
  validates :name, presence: true, uniqueness: true
end

下一步行动:

  def index
    @categories = Category.all.with_attached_image

    render json: @categories.to_json(include: { image_attachment: { include: :blob } })
  end

这是我获得图像对象的唯一方法。

我看到了下一个结果:

{"id":4,"name":"Cat1","description":""},
{"id":1,"name":"Cat2","description":"","image_attachment":
  {"id":8,"name":"image","record_type":"Category","record_id":1,"blob_id":8,"created_at":"2018-06-09T13:45:40.512Z","blob":
  {"id":8,"key":"3upLhH4vGxZEhhf3TaAjDiCW","filename":"Screen Shot 2018-06-09 at 20.43.24.png","content_type":"image/png","metadata":
  {"identified":true,"width":424,"height":361,"analyzed":true},"byte_size":337347,"checksum":"Y58zbYUVOlZRadx81wxOJA==","created_at":"2018-06-09T13:45:40.482Z"}}},
...

我可以在这里看到文件名。但是文件存在于不同的文件夹中,对我来说,这似乎不是获取和链接文件的方便方法。

我找不到关于这个的任何信息。

更新

根据igian解决方案,我的代码变成:

  def index
    @categories = Category.all.with_attached_image

    render json: @categories.map { |category|
      category.as_json.merge({ image: url_for(category.image) })
    }
  end