Written by Jamie Tanna
on 
CC-BY-NC-SA-4.0 Apache-2.0
2 mins

Introducing openapi-sorbet, a command-line tool for generating Sorbet types from OpenAPI

For a couple of the Ruby on Rails applications I work on at work, we use Sorbet for type checking.

Late last year we were integrating a JSON Schema based Lambda with the Rails application, so needed to create models to interact with it.

I started hacking on a command-line tool to generate the schemas, but ended up not finishing it, as it was straightforward enough to hand-write the models.

This week, I revisited the need to generate Sorbet types from OpenAPI when trying to integrate with an API, but finding that there wasn't a generator out there for Sorbet, I sought to build it myself.

I've released the first iteration of this, schema-sorbet which includes an OpenAPI-to-Sorbet command-line tool.

For instance, if we take the petstore example:

go install gitlab.com/tanna.dev/schema-sorbet/cmd/openapi-sorbet@latest
curl https://raw.githubusercontent.com/OAI/OpenAPI-Specification/main/examples/v3.0/petstore.yaml -Lo petstore.yaml
openapi-sorbet -path petstore.yaml -module ExternalClients::Petstore

This will output the following files for the #!/components/schemas in the OpenAPI spec:

out/external_clients/petstore/pets.rb:

# typed: strict
# frozen_string_literal: true

=begin
Generated from OpenAPI specification for
  Swagger Petstore 1.0.0
using
  openapi-sorbet version v0.4.0.
DO NOT EDIT.
=end
 module ExternalClients
 module Petstore
=begin
Pets
=end
Pets = T.type_alias { T::Array[Pet]}
end
end

out/external_clients/petstore/pet.rb:

# typed: strict
# frozen_string_literal: true

=begin
Generated from OpenAPI specification for
  Swagger Petstore 1.0.0
using
  openapi-sorbet version v0.4.0.
DO NOT EDIT.
=end
 module ExternalClients
 module Petstore
=begin
Pet
=end
class Pet  < T::Struct
extend T::Sig

const :id, Integer
const :name, String
const :tag, T.nilable(String)
end
end
end

out/external_clients/petstore/error.rb:

# typed: strict
# frozen_string_literal: true

=begin
Generated from OpenAPI specification for
Swagger Petstore 1.0.0
using
openapi-sorbet version (unknown).
DO NOT EDIT.
=end
module ExternalClients
module Petstore
=begin
Error
=end
class Error  < T::Struct
extend T::Sig

const :code, Integer
const :message, String
end
end
end

Note that these aren't formatted, so need some post-processing.

I've been using it so far with some fairly straightforward OpenAPI specifications, and it's been handy!

Written by Jamie Tanna's profile image Jamie Tanna on , and last updated on .

Content for this article is shared under the terms of the Creative Commons Attribution Non Commercial Share Alike 4.0 International, and code is shared under the Apache License 2.0.

#blogumentation #sorbet #ruby #go #command-line #openapi.

This blog post is 100% human-written, and has nothing derived from LLMs (be it code, editorial support or prose).

This post was filed under articles.

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