[BUG][Ruby] Unable to detect content type in form-data file upload using Faraday

[dvacca-onfido]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Using faraday as network library, generated ruby client is not able to detect the mime file type when performing file upload as part of a multipart/form-data payload, but it's just using application/octet-stream. That's hardcoded and it's not even possible to change that via some parameter. Looking at the generated code, there is a TODO we'd like to fix:

           when ::File, ::Tempfile
            # TODO hardcode to application/octet-stream, need better way to detect content type
            data[key] = Faraday::FilePart.new(value.path, 'application/octet-stream', value.path)

openapi-generator version

Issue found in version 7.2.0+ (haven't checked previous versions).

OpenAPI declaration file content or url

https://github.com/onfido/onfido-openapi-spec/blob/2f6f506977ecbb340b80c6d31a2dffcb3cedf2bb/generated/artifacts/openapi-yaml/openapi/openapi.yaml#L199-L222

Generation Details

inputSpec: /local/openapi.yaml
useOneOfDiscriminatorLookup: true
invokerPackage: Onfido
packageName: onfido-ruby
moduleName: Onfido
library: faraday

Steps to reproduce

require "onfido"

Onfido.configure do |config|
  config.api_key['Token'] = "Token token=#{ENV["API_KEY"]}"
  config.debugging = true
end

document = onfido_api.upload_document('passport', 'random-uuid', File.open('example.jpg'))

Logs:

{"type"=>"passport", "applicant_id"=>"random-uuid", "file"=>#<Multipart::Post::UploadIO:0x000000011e326508 @content_type="application/octet-stream", @original_filename="example.jpg", @local_path="example.jpg", @io=#<File:example.jpg>, @opts={}>}

For a jpg image, we'd have expected to have received image/jpeg in place of application/octet-stream.

Related issues/PRs

N/A

Suggest a fix

Use ruby-filemagic gem to detect the content type (PR coming soon).