openapi4s

OpenApi generators for Scala.

Here is a small video demo: https://youtu.be/kf0vGrlKNb8

Features and Benefits

• incremental generator
  • doesn't touch the code that you added manually
  • additive only, adds new properties/methods/classes
• lenient parser+generator
  • if something is not supported it will still (mostly) work
  • you can adapt your openapi spec to work gradually

Limitations

• JSON only
• only named entities, no anonymous objects

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Generators

Circe models backend

• discriminated models (sealed traits / enums)
• enums (singleton enums)

Tupson models backend

• discriminated models (sealed traits / enums)
• enums (singleton enums)

Sharaf framework backend

Supports almost all features:

• controllers
• validations
• query params

Http4s framework backend

Supports some features:

• routes (controllers)

TODO: query params, validation..
Contributions welcome!

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Usage

Mill plugin

See https://github.com/sake92/mill-openapi4s

CLI

You can use openapi4s-cli with Coursier launcher to generate your sources:

cs launch ba.sake::openapi4s-cli:0.6.1 -M ba.sake.openapi4s.cli.OpenApi4sMain -- \
  --models tupson \
  --framework sharaf \
  --url openapi.json \
  --baseFolder src \
  --basePackage com.example

You can now combine model and framework generation independently:

# circe models + http4s routes
--models circe --framework http4s

# circe models + sharaf controllers
--models circe --framework sharaf

# models only
--models tupson --framework none

# framework only (expects existing com.example.models)
--models none --framework http4s