Streamed hello world / published by https://github.com/dacr/code-examples-manager #ee6c3275-18d1-4651-a6fa-7b27371d09b2/72869f114f00b13635b288971d2236a23db898c5

tapir-zio-stream.sc

// summary : Streamed hello world
// keywords : scala, zio, tapir, http, zhttp, stream, @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 : ee6c3275-18d1-4651-a6fa-7b27371d09b2
// created-on : 2024-05-15T09:53:10+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file
// test-with : curl http://127.0.0.1:8080/hello

// ---------------------
//> using scala "3.4.2"
//> using dep "com.softwaremill.sttp.tapir::tapir-zio:1.10.7"
//> using dep "com.softwaremill.sttp.tapir::tapir-zio-http-server:1.10.7"
//> using dep "com.softwaremill.sttp.tapir::tapir-json-zio:1.10.7"
// ---------------------

import sttp.tapir.ztapir.*
import sttp.tapir.server.ziohttp.ZioHttpInterpreter
import zio.*
import zio.stream.*
import zio.json.*
import zio.http.Server
import sttp.capabilities.zio.ZioStreams
import sttp.model.{MediaType, StatusCode}
import sttp.tapir.{CodecFormat, Schema}
import sttp.tapir.generic.auto.*
import sttp.tapir.json.zio.*
import sttp.tapir.ztapir.*

case class Greeting(message:String) derives JsonCodec

case class JsonSeqCodecFormat() extends CodecFormat {
  override val mediaType: MediaType = MediaType.unsafeApply("application", "json-seq")
}

object WebApp extends ZIOAppDefault {

  // --------------------------------------------------
  val greetingStream: ZIO[Any, String, ZStream[Any, Throwable, Byte]] = ZIO.succeed(
    ZStream
      .repeat(Greeting("Hello world"))
      .schedule(Schedule.spaced(1.second))
      .flatMap(greeting => ZStream.fromIterable( (greeting.toJson+"\n").getBytes ))
  )

  val failingGreetingStream1: ZIO[Any, String, ZStream[Any, Throwable, Byte]] = ZIO.fail(
    "Can not build the stream"
  )

  val failingGreetingStream2: ZIO[Any, String, ZStream[Any, Throwable, Byte]] = ZIO.succeed(
    ZStream.fail(Exception("Can not build the stream"))
  ) // of course http success here

  val failingGreetingStream3: ZIO[Any, String, ZStream[Any, Throwable, Byte]] = ZIO.succeed(
    ZStream.fromJavaStreamZIO(
      ZIO.fail(Exception("Can not build the stream"))
    )
  ) // of course http success here

  val helloEndPoint =
    endpoint
      .description("Returns greeting")
      .get
      .in("hello")
      .out(streamBody(ZioStreams)(Schema.derived[Greeting], JsonSeqCodecFormat()))
      .out(statusCode(StatusCode.Ok).description("query success"))
      .errorOutVariantPrepend(oneOfVariant(StatusCode.InternalServerError, plainBody[String]))


  //val helloRoute = helloEndPoint.zServerLogic[Any](_ => greetingStream)
  val helloRoute = helloEndPoint.zServerLogic[Any](_ => failingGreetingStream3)

  val routes = ZioHttpInterpreter().toHttp(List(helloRoute))
  override def run = Server.serve(routes).provide(Server.default)
}

WebApp.main(Array.empty)