ActiveStorage raw file uploads fail with "An unknown file format not allowed" due filename being lost

[Alexey1100]

Bug report for Cloudinary Ruby SDK

Before proceeding, please update to latest version and test if the issue persists

Describe the bug in a sentence or two.

When uploading raw files (e.g. CSV) through the ActiveStorage integration, the Cloudinary API rejects the upload with CloudinaryException: An unknown file format not allowed.

This is a regression from the 1.x series, which used rest-client and preserved the original filename in multipart requests.

Issue Type (Can be multiple)

• Build - Cannot install or import the SDK
• Performance - Performance issues
• Behaviour - Functions are not working as expected (such as generate URL)
• Documentation - Inconsistency between the docs and behaviour
• Other (Specify)

Steps to reproduce

1. Configure ActiveStorage with the Cloudinary service (config/storage.yml):

   cloudinary:
     service: Cloudinary
     type: private

2. Configure a Cloudinary upload preset as the default for "API raw" with allowed_formats: ["csv"]
3. Create a model with has_one_attached :csv_file
4. Upload a .csv file through ActiveStorage
5. Observe the error:

   ActiveStorage::IntegrityError (An unknown file format not allowed)
   Caused by: CloudinaryException (An unknown file format not allowed)

Error screenshots or Stack Trace (if applicable)

…

Operating System

• Linux
• Windows
• macOS
• All

Environment and Libraries (fill in the version numbers)

• Cloudinary Ruby SDK version - 2.1.2
• Ruby Version - 3.4.1
• Rails Version - 8.1.2
• Other Libraries (Carrierwave, ActiveStorage, etc) - 0.0.0

Repository

If possible, please provide a link to a reproducible repository that showcases the problem

Suggested Fix

In lib/active_storage/service/cloudinary_service.rb, the upload method should pass the filename to the uploader as original_filename:

def upload(key, io, filename: nil, checksum: nil, **options)
  instrument :upload, key: key, checksum: checksum do
    begin
      extra_headers = checksum.nil? ? {} : {Headers::CONTENT_MD5 => checksum}
      options = @options.merge(options)
      options[:original_filename] = filename.to_s if filename.present?  # <-- add this
      resource_type = resource_type(io, key)
      options[:format] = ext_for_file(key) if resource_type == "raw"
      Cloudinary::Uploader.upload_large(
        io,
        # ... rest unchanged
      )
    end
  end
end

[skalahasti-cloudinary]

Hi @Alexey1100 ,

Thanks for posting the issue.

Can you please confirm what is the value that is being set for format when calling ext_for_file(key)?

Thanks,
Sree

[Alexey1100]

Hello @skalahasti-cloudinary
Looks like it returns "csv", for my example above.

[dejihastrup-cl]

Hi @Alexey1100,

Thanks for following up.

It looks like this may be related to the resource_type being set when using type: private. If resource_type is not explicitly set, the upload can fail with “unknown file format not allowed” even when the format is permitted in the preset.

Could you please try adding :resource_type => auto to the upload options and see if the issue persists?

Best Regards,
Deji