ActiveStorage & S3: Make files public

问题

In my rails application, some images should be public and others should be private. (I don't mind to have all of them public).

Currently, when calling ActiveStorage's service_url (when using s3), a new presigned url is being generated. I totally understand this, but it's not what I want to do.

Right now, generating the presigned url is taking too much time:

Example:

Getting 10 records:

ActiveRecord: 52.3ms
Generating the JSON: 1,790ms

If we dig deeper, we see the following:

S3 Storage (23.9ms) Checked if file exists at key: variants/p5Enur12ZMUEgMb6niJDtS2W/6cb99d2f2eca3bafc444d3c7cdfab34cd303f2578891852655d60028981c8950 (yes)
S3 Storage (3.2ms) Generated URL for file at key: variants/p5Enur12ZMUEgMb6niJDtS2W/6cb99d2f2eca3bafc444d3c7cdfab34cd303f2578891852655d60028981c8950

In my example, I'm getting 10 Matches, where each Match has teams and competition. Team and Competition have one image.

I'm also generating the following JSON Structure:

{
  ...
  image: {
    original: ...,
    thumbnail: ...,
    medium: ...,
    large: ...,
  }
}

With this taken into consideration, here are the numbers:

10 matches * ( 1 team + 1 competition ) = 20 images
each image has 4 sizes
each size takes around 27ms
--> 20 * 4 * 27 = ~2,160ms

Is there a way to make all the uploaded files public and we'll have the 2,160ms completely removed ?

---

Edit: answer

def url_for_file(file:, size: nil, process: false)
  s3_storage = Rails.application.config.active_storage.service == :amazon

  if size.nil?
    url = file
  else
    url = file.variant(size)

    if process
      url = url.processed
    end
  end

  if s3_storage
    amazon_config = Rails.application.config.active_storage.service_configurations.amazon
    return "https://s3.#{amazon_config.region}.amazonaws.com/#{amazon_config.bucket}/#{url.key}"
  else
    return url.service_url
  end
end

With this small hack, you will only process the files when you want ( and assume they are processed when presenting ), also, won't call .service_url which checks if the file exists. This is only valid if your acl config is public.

来源：https://stackoverflow.com/questions/57946351/activestorage-s3-make-files-public

标签

ruby-on-rails

amazon-s3

rails-activestorage