Example.scala

package example

import zio.schema.*
import zio.http.*
import zio.http.endpoint.*
import zio.*
import zio.http.Method.*
import zio.http.codec.ContentCodec
import zio.http.codec.HeaderCodec
import zio.http.Header.ContentType

case class Foo(bars: List[Int]) derives Schema

object App extends zio.ZIOAppDefault:
  val unexpected = Endpoint(POST / "unexpected").in[Foo].out[Foo]
  val expected =
    import zio.json.*
    given fooCodec: JsonCodec[Foo] =
      schema.codec.JsonCodec.jsonCodec(Foo.derived$Schema)
    Endpoint(POST / "expected")
      .in[Foo]
      .out[Foo]
      .outCodec(
        ContentCodec
          .content[String](MediaType.text.plain)
          .transformOrFail(s => s.fromJson[Foo])(e => Right(e.toJson))
      )
      .outHeader(HeaderCodec.contentType)
      .transformOut((foo, _) => foo)(foo =>
        (foo, ContentType(MediaType.application.json))
      )
  val routes = Routes(
    unexpected.implement(foo => ZIO.succeed(foo)),
    expected.implement(foo => ZIO.succeed(foo))
  )
  def checkRoute(path: String, foo: Foo) =
    import zio.schema.codec.JsonCodec.*
    routes
      .apply(
        Request(
          Version.`HTTP/1.1`,
          POST,
          URL.decode(path).toOption.get,
          Headers.apply(Header.Accept(MediaType.application.json)),
          Body.from(foo),
          None,
          None
        )
      )
      .flatMap(_.body.asString)
  def run =
    for
      _ <- checkRoute("/unexpected", Foo(List(1, 2, 3))).debug("unexpected")
      _ <- checkRoute("/expected", Foo(List(1, 2, 3))).debug("expected")
      _ <- checkRoute("/unexpected", Foo(Nil)).debug("unexpected")
      _ <- checkRoute("/expected", Foo(Nil)).debug("expected")
    yield ()