workin on JWT Emmiter and trying to understand how zio handles exceptions

JWTEmitter/src/org/tbasket/jwt/JwtGeneration.scala

@@ -1,12 +0,0 @@
-package org.tbasket.jwt
-
-import zio.Task
-import zio.http.{Request, Response}
-
-object JwtGeneration {
-  
-  def generateTokenResponse(request: Request): Task[Response] = {
-    ???
-  }
-  
-}

JWTEmitter/src/org/tbasket/jwt/JwtGenerator.scala

@@ -0,0 +1,35 @@
+package org.tbasket.jwt
+
+import pdi.jwt.*
+import zio.*
+import zio.http.{Request, Response}
+import zio.json.*
+import zio.json.ast.Json
+
+import java.lang.System.currentTimeMillis
+import java.nio.file.*
+import java.security.Key
+import java.security.interfaces.RSAPrivateKey
+import java.security.spec.PKCS8EncodedKeySpec
+import java.util.concurrent.TimeUnit
+import java.util.{Date, UUID}
+import javax.crypto.SecretKey
+import scala.concurrent.duration
+
+object JwtGenerator:
+
+  private val ExpirationDate = Duration(15, TimeUnit.DAYS).toMillis
+  private val Key = Files.readString(Path.of("id_rsa"))
+
+  private def claims(content: String) = JwtClaim(
+    expiration = Some(currentTimeMillis() + ExpirationDate),
+    issuedAt = Some(currentTimeMillis()),
+    jwtId = Some(UUID.randomUUID().toString),
+    content = content
+  )
+
+  def generateTokenResponse(request: Request): Task[Response] =
+    for
+      claims <- request.body.asString.map(claims)
+      jwt <- ZIO.attempt(JwtZIOJson.encode(claims, Key, JwtAlgorithm.RS256))
+    yield Response.json(jwt)

JWTEmitter/src/org/tbasket/jwt/Main.scala

@@ -4,34 +4,40 @@ import zio.*
 import zio.stream.*
 import zio.http.*
 import zio.http.ServerConfig.LeakDetectionLevel
-import zio.http.model.Method
-
-object Main extends ZIOAppDefault {
-  
-  private val app = Http.collectZIO[Request] {
-    case r@Method.POST -> !! / "/jwt" =>
-      JwtGeneration.generateTokenResponse(r)
-    
+import zio.http.model.{Method, Status}
+
+import java.nio.file.Files
+
+object Main extends ZIOAppDefault:
+
+  private def port(args: Chunk[String]): Task[Int] =
+    args.headOption match
+      case None => ZIO.dieMessage("Must provide the port argument")
+      case Some(head) => head.toIntOption match
+          case Some(port) if port > 0 && port < 65536 => ZIO.succeed(port)
+          case Some(oorPort) => ZIO.dieMessage(s"'$oorPort' is out of range.'")
+          case None => ZIO.dieMessage("given argument is not a valid integer")
+
+  private val app = Http.collectZIO[Request][Any, Throwable, Response] {
+    case r @ Method.GET -> _ / "jwt" =>
+      ZIO.attempt(JwtGenerator)
+        .flatMap(_.generateTokenResponse(r))
+        .catchAll(e => ZIO.die(e))
+    case _ =>
+      ZIO.succeed(Response(status = Status.NotFound))
   }
 
-  val run =
-    ZIO.serviceWithZIO[ZIOAppArgs] { args =>
-      for
-        port <- ZIO.attempt(args.getArgs)
-          .map(_.head)
-          .mapError(_ => Console.printError("Must provide at least one argument"))
-          .map(_.toInt)
-          .mapError(_ => Console.printError("Port is not a number"))
-          .filterOrFail(p => 0 < p && p < 65563)(Console.printError("Port is out of range"))
-      
-      yield
+  private def startServer(port: Int) =
     val config = ServerConfig.default
       .port(port)
       .leakDetection(LeakDetectionLevel.PARANOID)
 
     val configLayer = ServerConfig.live(config)
-        (Server.install(app) *> Console.printLine("JWT AppToken open on port") *> ZIO.never)
-          .provideSome(configLayer, Server.live)
-    }
+    (Server.install(
+      app
+    ) *> Console.printLine(s"JWT AppToken open on port $port") *> ZIO.never)
+      .provide(configLayer, Server.live)
 
-}
+  val run =
+    ZIO.serviceWithZIO[ZIOAppArgs](args => port(args.getArgs))
+      .flatMap(startServer)

build.sc

@@ -5,6 +5,7 @@ trait ServerModule extends ScalaModule with ScalafmtModule {
     //override def scalacOptions = Seq("-explain")
     
     override final def scalaVersion = "3.2.0"
+  
     override def ivyDeps = Agg(
         ivy"dev.zio::zio:2.0.6",
         ivy"org.apache.logging.log4j:log4j-slf4j-impl:2.19.0"
@@ -14,7 +15,8 @@ trait HttpModule extends ServerModule {
     override def ivyDeps = super.ivyDeps() ++ Agg(
         ivy"dev.zio::zio-http:0.0.3",
         ivy"dev.zio::zio-json:0.4.2",
-        ivy"dev.zio::zio-streams:2.0.6"
+        ivy"dev.zio::zio-streams:2.0.6",
+        ivy"com.github.jwt-scala::jwt-zio-json:9.1.2"
     )
 }