ZIO learning - an enhanced authentication service using a http service / published by https://github.com/dacr/code-examples-manager #597f2fb2-15e1-4d28-aefd-37dc463ed4f7/da2712a2ed96fb6bb6f7d4c8bd506b5ea21813ae

zio-learning-14-service-3.sc

// summary : ZIO learning - an enhanced authentication service using a http service
// keywords : scala, zio, learning, authentication, pure-functional, @testable
// 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 : 597f2fb2-15e1-4d28-aefd-37dc463ed4f7
// created-on : 2021-05-01T21:42:05+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala  "3.2.2"
//> using dep "dev.zio::zio:2.0.13"
//> using dep "fr.janalyse::zio-worksheet:2.0.13.0"
// ---------------------
import zio.*, zio.worksheet.*

// -------------------------------------------------------------
trait HttpService:
  def httpGet(query: String): Task[String]

case class HttpServiceLive() extends HttpService:
  override def httpGet(query: String): Task[String] =
    for
      httpProxy <- System.env("http_proxy")
      body      <- ZIO.succeed("secured-auth-token")
    yield body

object HttpService:
  val live = ZLayer.succeed(HttpServiceLive())

  def httpGet(query: String): RIO[HttpService, String] = ZIO.serviceWithZIO(_.httpGet(query))

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

case class AuthToken(token: String)

trait Authenticator:
  def authenticate: Task[AuthToken]

case class AuthenticatorLive(httpService: HttpService) extends Authenticator:
  override def authenticate: Task[AuthToken] =
    for
      username <- System.env("APP_USERNAME")
      password <- System.env("APP_PASSWORD")
      body     <- httpService.httpGet("http://127.0.0.1/auth")
      token     = "secured-auth-token"
    yield AuthToken(token)

object Authenticator:
  val live = ZLayer(
    for httpService <- ZIO.service[HttpService]
    yield AuthenticatorLive(httpService)
  )

  def authenticate: RIO[Authenticator, AuthToken] = ZIO.serviceWithZIO(_.authenticate)

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

val app: ZIO[Authenticator, Throwable, Unit] =
  for
    _     <- Console.printLine("started")
    token <- Authenticator.authenticate
    _     <- Console.printLine(s"got token $token")
  yield ()

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

app.provideLayer(HttpService.live >>> Authenticator.live).unsafeRun