[BUG] [Ruby] Client does not form-encode PUT requests

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

The Ruby client relies on Typhoeus to make http requests. Due to typhoeus/typhoeus#389 the generated Ruby client does not form encode PUT requests even when the Content-Type is supposed to be 'multipart/form-data'. POST requests are form-encoded just fine.

openapi-generator version

latest master branch

OpenAPI declaration file content or url

https://docs.pulpproject.org/en/3.0/nightly/api.json

Command line used for generation

docker run -u $(id -u) --rm -v ${PWD}:/local openapitools/openapi-generator-cli generate \
    -i /local/api.json \
    -g ruby \
    -o /local/pulpcore-client \
    -DgemName=pulpcore_client \
    -DgemLicense="GPLv2" \
    -DgemVersion=3.0.0rc2 \
    --skip-validate-spec \
    --strict-spec=false

Steps to reproduce

require 'pulpcore_client'
PulpcoreClient.configure do |config|
          config.host= "http://localhost:24817"
          config.username= 'admin'
          config.password= 'admin'
end

api_instance = PulpcoreClient::UploadsApi.new
content_range = "bytes 0-2373/2373" # String | The Content-Range header specifies the location of the file chunk within the file.

file = File.new('katello.gemspec') # File | A chunk of a file to upload.

begin
  #Start Upload
  result = api_instance.uploads_create(content_range, file)
  p result
rescue PulpcoreClient::ApiError => e
  puts "Exception when calling UploadsApi->uploads_create: #{e}"
end

Related issues/PRs

https://github.com/swagger-api/swagger-codegen/issues/7889
https://github.com/typhoeus/typhoeus/issues/389

Suggest a fix

Add ability to use a different library to perform requests.

Start by reproducing the generated Ruby client request using the provided Docker generation command and the UploadsApi example. Read the Ruby client request path and the linked Typhoeus issue first; done means multipart/form-data PUT requests are form-encoded correctly without breaking the existing POST behavior.