ZIO HTTP basic app example

March 17, 2021

ZIO-HTTP is a new ZIO lib for HTTP applications creation.
It integrates very naturally with ZIO.

Here is a very simple example using ZIO effects and dependency injection with ZLayer :

	import zio._
	import zhttp.http._
	import zhttp.http.HttpError.InternalServerError
	import zhttp.service.Server
	import zio.clock.Clock

	import java.time.DateTimeException

	object HelloWorld extends App {

	val app = Http.collectM[Request] {
	case Method.GET -> Root / "hello" =>
	HelloWorldService.helloWorld.fold({
	//error case(s) :
	case dateTimeError: DateTimeException =>
	Response.fromHttpError(InternalServerError("Internal error : " + dateTimeError.getMessage))
	},
	// success case :
	message => Response.text(message)
	)
	// you can add more routes here :
	// case Method.GET -> Root / "fruits" => ...
	}

	override def run(args: List[String]) = {
	val serverIO = Server.start(8090, app).provideLayer(Clock.live) // <- bind clock implementation
	serverIO.exitCode
	}
	}

	object HelloWorldService {

	val clock = ZIO.access[Clock](_.get) // <- dependency injection : can use Clock.live, or a fake clock for tests

	def helloWorld: ZIO[Clock, DateTimeException, String] =
	for {
	c <- clock
	time <- c.localDateTime
	} yield s"Hello world, the current date is $time"
	}

view raw HelloZioHttp.scala hosted with ❤ by GitHub