Fetch the definition live from a KORONA instance and regenerate from it:

• https://128.koronacloud.com/web/api/v3/openapi.json — OpenAPI 3.1, the newest and most complete spec. Use this. (Any <instance>.koronacloud.com host serves the same definition.)

Deprecated / stale sources, for reference only:

• https://128.koronacloud.com/web/api/v3/swagger.json — deprecated; the endpoint now just tells you to use openapi.json.
• https://support.korona.de/misc/korona-cloud-api-v3/swagger.196.json — a static Swagger 2.0 export on the support site, several versions behind the live spec.

Note: KORONA periodically returns enum values that are not yet in any published spec (e.g. new dsfinvkTaxKeys). The stock generator raises ArgumentError while deserializing such responses, so the enum-setter template override below is required in addition to regenerating from the newest spec — regeneration fixes today's known values, the override survives the next undocumented one.

npm install @openapitools/openapi-generator-cli -g

openapi-generator-cli version-manager list

Download the live definition and downgrade the declared OpenAPI version from 3.1.0 to 3.0.3. The spec uses no actual 3.1 features, but openapi-generator (all 7.x versions tested) crashes with a NullPointerException the moment it sees "openapi": "3.1.0" — flipping the version string makes its mature 3.0 parser handle the same content cleanly.

curl -fsSL https://128.koronacloud.com/web/api/v3/openapi.json \
  | ruby -rjson -e 'd=JSON.parse($stdin.read); d["openapi"]="3.0.3"; print JSON.generate(d)' > swagger.json

npx @openapitools/openapi-generator-cli generate -i swagger.json -g ruby -o gem -t templates \
--skip-validate-spec \
--package-name korona-cloud-client -p gemName=korona-cloud-client -p gemVersion=1.0.13 \
-p gemHomepage=https://github.com/giantmonkey/korona-cloud-client

--skip-validate-spec is required because the downgraded doc trips the 3.0 validator on a couple of benign points (e.g. an empty {} schema at Coupon/properties/external).

-t templates applies our local overrides in templates/. Currently this customizes partial_model_generic.mustache so enum setters tolerate unknown values instead of raising: the KORONA API ships enum values (e.g. new dsfinvkTaxKeys) that are not in its own published swagger.json, and the stock generator raises ArgumentError while deserializing such responses, crashing otherwise-valid API calls. Files not present in templates/ fall back to the generator's built-ins, so the override stays minimal. Re-extract pristine templates with openapi-generator-cli author template -g ruby -o /tmp/pristine when diffing against a new generator version.

update the gem version before running this:

brew install openapi-generator
openapi-generator generate -i swagger.json -g ruby -o gem --package-name korona-cloud-client \
-p gemName=korona-cloud-client -p gemHomepage=https://github.com/giantmonkey/korona-cloud-client -p gemVersion=1.0.13

(all ruby options: https://openapi-generator.tech/docs/generators/ruby/ )

cd gem
mv spec/models/promotion_benefit_extended_discount_position_selection_criteria_min_max_range_value_comperator_spec.rb spec/models/promotion_benefit_extended_discount_position_selection_comperator_spec.rb
gem build korona-cloud-client.gemspec

gem push korona-cloud-client-1.0.10.gem

config = KoronaCloudClient::Configuration.new do |config|
  config.username = '<KORONA_API_USERNAME>'
  config.password = '<KORONA_API_PASSWORD>'
  config.host     = '<HOST>.koronacloud.com'
end

api_client    = KoronaCloudClient::ApiClient.new config
products_api  = KoronaCloudClient::ProductsApi.new api_client
products      = products_api.get_products('<ACCOUNT_ID>')