http server random hello world using sealed traits or union types - experiments / published by https://github.com/dacr/code-examples-manager #5a1b725d-853a-45c6-9d9d-612f67174552/7944c5966360c2ce1072e1e6207f378bd913a750

tapir-zio-hello-sealed-traits-pickler.sc

// summary : http server random hello world using sealed traits or union types - experiments
// keywords : scala, zio, tapir, http, zhttp, @testable, @exclusive
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 5a1b725d-853a-45c6-9d9d-612f67174552
// created-on : 2024-01-24T09:46:26+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file
// test-with : curl -L http://127.0.0.1:8080/hello

// ---------------------
//> using scala "3.4.2"
//> using dep "com.softwaremill.sttp.tapir::tapir-zio:1.9.6"
//> using dep "com.softwaremill.sttp.tapir::tapir-json-zio:1.9.6"
//> using dep "com.softwaremill.sttp.tapir::tapir-json-pickler:1.9.6"
//> using dep "com.softwaremill.sttp.tapir::tapir-zio-http-server:1.9.6"
//> using dep "com.softwaremill.sttp.tapir::tapir-swagger-ui-bundle:1.9.6"
// ---------------------

import zio.*
import zio.http.Server
//import zio.json.{JsonCodec, jsonDiscriminator}
//import sttp.tapir.json.zio.*
import sttp.tapir.json.pickler.*
import sttp.tapir.Codec.JsonCodec
import sttp.tapir.ztapir.*
import sttp.tapir.server.ziohttp.ZioHttpInterpreter
import sttp.apispec.openapi.Info
import sttp.tapir.generic.Configuration
import sttp.tapir.swagger.bundle.SwaggerInterpreter
import sttp.tapir.generic.auto.*

/*
curl -L http://127.0.0.1:8080/docs
 */

object WebApp extends ZIOAppDefault {
  // -------------------------------------------------------------------------
  sealed trait Feedback
  case class Message(userText: String) extends Feedback

  sealed trait Greetings
  case class Simple(message: Message)                extends Greetings
  case class Polite(bodyTile: Int, message: Message) extends Greetings

  // -------------------------------------------------------------------------
  implicit val tapirConfig: Configuration =
    Configuration.default
      .withDiscriminator("@kind")
      .withKebabCaseMemberNames
      .withKebabCaseDiscriminatorValues

  implicit lazy val feedbackRW: upickle.default.ReadWriter[Feedback] = upickle.default.macroRW
  implicit lazy val messageRW: upickle.default.ReadWriter[Message]   = upickle.default.macroRW

  implicit lazy val greetingsRW: upickle.default.ReadWriter[Greetings] = upickle.default.macroRW
  implicit lazy val simpleRW: upickle.default.ReadWriter[Simple]       = upickle.default.macroRW
  implicit lazy val politeRW: upickle.default.ReadWriter[Polite]       = upickle.default.macroRW

  implicit lazy val feedbackPickler: Pickler[Feedback] = Pickler.derived
  implicit lazy val feedbackCodec: JsonCodec[Feedback] = feedbackPickler.toCodec

  implicit lazy val messagePickler: Pickler[Message] = Pickler.derived
  implicit lazy val messageCodec: JsonCodec[Message] = messagePickler.toCodec

  implicit lazy val greetingsPickler: Pickler[Greetings] = Pickler.derived
  implicit lazy val greetingsCodec: JsonCodec[Greetings] = greetingsPickler.toCodec

  implicit lazy val simplePickler: Pickler[Simple] = Pickler.derived
  implicit lazy val simpleCodec: JsonCodec[Simple] = simplePickler.toCodec

  implicit lazy val politePickler: Pickler[Polite] = Pickler.derived
  implicit lazy val politeCodec: JsonCodec[Polite] = politePickler.toCodec

  val helloEndPoint =
    endpoint
      .description("say hello")
      .get
      .in("hello")
      .out(jsonBody[Feedback])

  val helloRoute = helloEndPoint.zServerLogic[Any](_ => ZIO.succeed(Message("Hello")))

  // --------------------------------------------------
  val greetingEndPoint =
    endpoint
      .description("Return random greeting")
      .get
      .in("greeting")
      .out(jsonBody[Greetings])

  val greetings = List[Greetings](
    Simple(Message("Hi")),
    Simple(Message("Hello")),
    Polite(30, Message("Nice to meed you"))
  )

  val greetingRoute = greetingEndPoint.zServerLogic[Any](_ => Random.shuffle(greetings).map(_.head))

  // --------------------------------------------------

  val docEndpoints =
    SwaggerInterpreter()
      .fromServerEndpoints(
        List(helloRoute, greetingRoute),
        Info(title = "Greeting API", version = "1.0", description = Some("Everything required to be polite"))
      )

  // --------------------------------------------------

  val routes = ZioHttpInterpreter().toHttp(List(helloRoute, greetingRoute) ++ docEndpoints)

  // --------------------------------------------------

  override def run =
    Server
      .serve(routes)
      .provide(Server.default)
}

WebApp.main(Array.empty)