Make LiveChannel thread safe

core/src/scalive/WebSocketMessage.scala

@@ -0,0 +1,102 @@
+package scalive
+
+import scalive.WebSocketMessage.LiveResponse
+import scalive.WebSocketMessage.Payload
+import scalive.WebSocketMessage.Payload.EventType
+import zio.Chunk
+import zio.json.*
+import zio.json.ast.Json
+
+final case class WebSocketMessage(
+  // Live session ID, auto increment defined by the client on join
+  joinRef: Option[Int],
+  // Message ID, global auto increment defined by the client on every message
+  messageRef: Int,
+  // LiveView instance id
+  topic: String,
+  eventType: String,
+  payload: WebSocketMessage.Payload)
+object WebSocketMessage:
+  given JsonCodec[WebSocketMessage] = JsonCodec[Json].transformOrFail(
+    {
+      case Json.Arr(
+            Chunk(joinRef, Json.Str(messageRef), Json.Str(topic), Json.Str(eventType), payload)
+          ) =>
+        val payloadParsed = eventType match
+          case "heartbeat" => Right(Payload.Heartbeat)
+          case "phx_join"  => payload.as[Payload.Join]
+          case "event"     => payload.as[Payload.Event]
+          case s           => Left(s"Unknown event type : $s")
+
+        payloadParsed.map(
+          WebSocketMessage(
+            joinRef.asString.map(_.toInt),
+            messageRef.toInt,
+            topic,
+            eventType,
+            _
+          )
+        )
+      case v => Left(s"Could not parse socket message ${v.toJson}")
+    },
+    m =>
+      Json.Arr(
+        m.joinRef.map(ref => Json.Str(ref.toString)).getOrElse(Json.Null),
+        Json.Str(m.messageRef.toString),
+        Json.Str(m.topic),
+        Json.Str(m.eventType),
+        m.payload.match
+          case Payload.Heartbeat => Json.Obj.empty
+          case p: Payload.Join   => p.toJsonAST.getOrElse(throw new IllegalArgumentException())
+          case p: Payload.Reply  => p.toJsonAST.getOrElse(throw new IllegalArgumentException())
+          case p: Payload.Event  => p.toJsonAST.getOrElse(throw new IllegalArgumentException())
+      )
+  )
+
+  enum Payload:
+    case Heartbeat
+    case Join(
+      url: String,
+      // params: Map[String, String],
+      session: String,
+      static: Option[String],
+      sticky: Boolean)
+    case Reply(status: String, response: LiveResponse)
+    case Event(`type`: Payload.EventType, event: String, value: Map[String, String])
+  object Payload:
+    given JsonCodec[Payload.Join]    = JsonCodec.derived
+    given JsonEncoder[Payload.Reply] = JsonEncoder.derived
+    given JsonCodec[Payload.Event]   = JsonCodec.derived
+
+    enum EventType:
+      case Click
+    object EventType:
+      given JsonCodec[EventType] = JsonCodec[String].transformOrFail(
+        {
+          case "click" => Right(Click)
+          case s       => Left(s"Unsupported event type: $s")
+        },
+        { case Click =>
+          "click"
+        }
+      )
+
+  enum LiveResponse:
+    case Empty
+    case InitDiff(rendered: scalive.Diff)
+    case Diff(diff: scalive.Diff)
+  object LiveResponse:
+    given JsonEncoder[LiveResponse] =
+      JsonEncoder[Json].contramap {
+        case Empty              => Json.Obj.empty
+        case InitDiff(rendered) =>
+          Json.Obj(
+            "liveview_version" -> Json.Str("1.1.8"),
+            "rendered"         -> rendered.toJsonAST.getOrElse(throw new IllegalArgumentException())
+          )
+        case Diff(diff) =>
+          Json.Obj(
+            "diff" -> diff.toJsonAST.getOrElse(throw new IllegalArgumentException())
+          )
+      }
+end WebSocketMessage

zio/src/scalive/LiveRouter.scala

@@ -1,15 +1,13 @@
 package scalive
 
-import scalive.SocketMessage.LiveResponse
+import scalive.WebSocketMessage.LiveResponse
-import scalive.SocketMessage.Payload
+import scalive.WebSocketMessage.Payload
-import scalive.SocketMessage.Payload.EventType
 import zio.*
 import zio.http.*
 import zio.http.ChannelEvent.Read
 import zio.http.codec.PathCodec
 import zio.http.template.Html
 import zio.json.*
-import zio.json.ast.Json
 
 import java.util.Base64
 import scala.collection.mutable
@@ -43,67 +41,82 @@ final case class LiveRoute[A, ClientEvt: JsonCodec, ServerEvt](
       )
     }
 
-class LiveChannel():
+class LiveChannel(semaphore: Semaphore):
-  // TODO not thread safe
   private val sockets: mutable.Map[String, Socket[?, ?]] = mutable.Map.empty
 
   // TODO should check id isn't already present
-  def join[ClientEvt: JsonCodec](id: String, token: String, lv: LiveView[ClientEvt, ?]): Diff =
+  def join[ClientEvt: JsonCodec](id: String, token: String, lv: LiveView[ClientEvt, ?]): UIO[Diff] =
+    semaphore.withPermit {
+      ZIO.succeed {
         val socket = Socket(id, token, lv)
         sockets.addOne(id, socket)
         socket.diff
+      }
+    }
 
   // TODO handle missing id
-  def event(id: String, value: String): Diff =
+  def event(id: String, value: String): UIO[Diff] =
+    semaphore.withPermit {
+      ZIO.succeed {
         val s = sockets(id)
         s.lv.handleClientEvent(
           value
-        .fromJson(using s.clientEventCodec.decoder).getOrElse(throw new IllegalArgumentException())
+            .fromJson(using s.clientEventCodec.decoder).getOrElse(
+              throw new IllegalArgumentException()
+            )
         )
         s.diff
+      }
+    }
+
+object LiveChannel:
+  def make(): UIO[LiveChannel] =
+    Semaphore.make(permits = 1).map(new LiveChannel(_))
 
 class LiveRouter(rootLayout: HtmlElement => HtmlElement, liveRoutes: List[LiveRoute[?, ?, ?]]):
 
   private val socketApp: WebSocketApp[Any] =
-    val liveChannel = new LiveChannel()
     Handler.webSocket { channel =>
+      LiveChannel
+        .make().flatMap(liveChannel =>
           channel
             .receiveAll {
               case Read(WebSocketFrame.Text(content)) =>
                 for
                   message <- ZIO
-                           .fromEither(content.fromJson[SocketMessage])
+                               .fromEither(content.fromJson[WebSocketMessage])
                                .mapError(new IllegalArgumentException(_))
                   reply <- handleMessage(message, liveChannel)
                   _     <- channel.send(Read(WebSocketFrame.text(reply.toJson)))
                 yield ()
               case _ => ZIO.unit
             }.tapErrorCause(ZIO.logErrorCause(_))
+        )
     }
 
-  private def handleMessage(message: SocketMessage, liveChannel: LiveChannel): Task[SocketMessage] =
+  private def handleMessage(message: WebSocketMessage, liveChannel: LiveChannel)
+    : Task[WebSocketMessage] =
     val reply = message.payload match
       case Payload.Heartbeat => ZIO.succeed(Payload.Reply("ok", LiveResponse.Empty))
       case Payload.Join(url, session, static, sticky) =>
         ZIO
-          .fromEither(URL.decode(url)).map(url =>
+          .fromEither(URL.decode(url)).flatMap(url =>
             val req = Request(url = url)
             liveRoutes
               .collectFirst { route =>
                 val pathParams = route.path.decode(req.path).getOrElse(???)
                 val lv         = route.liveviewBuilder(pathParams, req)
-                val diff       =
                 liveChannel.join(message.topic, session, lv)(using route.clientEventCodec)
-                Payload.Reply("ok", LiveResponse.InitDiff(diff))
 
               }.getOrElse(???)
-          )
+          ).map(diff => Payload.Reply("ok", LiveResponse.InitDiff(diff)))
       case Payload.Event(_, event, _) =>
-        val diff = liveChannel.event(message.topic, event)
+        liveChannel
-        ZIO.succeed(Payload.Reply("ok", LiveResponse.Diff(diff)))
+          .event(message.topic, event)
+          .map(diff => Payload.Reply("ok", LiveResponse.Diff(diff)))
       case Payload.Reply(_, _) => ZIO.die(new IllegalArgumentException())
 
-    reply.map(SocketMessage(message.joinRef, message.messageRef, message.topic, "phx_reply", _))
+    reply.map(WebSocketMessage(message.joinRef, message.messageRef, message.topic, "phx_reply", _))
 
   val routes: Routes[Any, Response] =
     Routes.fromIterable(
@@ -114,97 +127,3 @@ class LiveRouter(rootLayout: HtmlElement => HtmlElement, liveRoutes: List[LiveRo
         )
     )
 end LiveRouter
-
-final case class SocketMessage(
-  // Live session ID, auto increment defined by the client on join
-  joinRef: Option[Int],
-  // Message ID, global auto increment defined by the client on every message
-  messageRef: Int,
-  // LiveView instance id
-  topic: String,
-  eventType: String,
-  payload: SocketMessage.Payload)
-object SocketMessage:
-  given JsonCodec[SocketMessage] = JsonCodec[Json].transformOrFail(
-    {
-      case Json.Arr(
-            Chunk(joinRef, Json.Str(messageRef), Json.Str(topic), Json.Str(eventType), payload)
-          ) =>
-        val payloadParsed = eventType match
-          case "heartbeat" => Right(Payload.Heartbeat)
-          case "phx_join"  => payload.as[Payload.Join]
-          case "event"     => payload.as[Payload.Event]
-          case s           => Left(s"Unknown event type : $s")
-
-        payloadParsed.map(
-          SocketMessage(
-            joinRef.asString.map(_.toInt),
-            messageRef.toInt,
-            topic,
-            eventType,
-            _
-          )
-        )
-      case v => Left(s"Could not parse socket message ${v.toJson}")
-    },
-    m =>
-      Json.Arr(
-        m.joinRef.map(ref => Json.Str(ref.toString)).getOrElse(Json.Null),
-        Json.Str(m.messageRef.toString),
-        Json.Str(m.topic),
-        Json.Str(m.eventType),
-        m.payload.match
-          case Payload.Heartbeat => Json.Obj.empty
-          case p: Payload.Join   => p.toJsonAST.getOrElse(throw new IllegalArgumentException())
-          case p: Payload.Reply  => p.toJsonAST.getOrElse(throw new IllegalArgumentException())
-          case p: Payload.Event  => p.toJsonAST.getOrElse(throw new IllegalArgumentException())
-      )
-  )
-
-  enum Payload:
-    case Heartbeat
-    case Join(
-      url: String,
-      // params: Map[String, String],
-      session: String,
-      static: Option[String],
-      sticky: Boolean)
-    case Reply(status: String, response: LiveResponse)
-    case Event(`type`: Payload.EventType, event: String, value: Map[String, String])
-  object Payload:
-    given JsonCodec[Payload.Join]    = JsonCodec.derived
-    given JsonEncoder[Payload.Reply] = JsonEncoder.derived
-    given JsonCodec[Payload.Event]   = JsonCodec.derived
-
-    enum EventType:
-      case Click
-    object EventType:
-      given JsonCodec[EventType] = JsonCodec[String].transformOrFail(
-        {
-          case "click" => Right(Click)
-          case s       => Left(s"Unsupported event type: $s")
-        },
-        { case Click =>
-          "click"
-        }
-      )
-
-  enum LiveResponse:
-    case Empty
-    case InitDiff(rendered: scalive.Diff)
-    case Diff(diff: scalive.Diff)
-  object LiveResponse:
-    given JsonEncoder[LiveResponse] =
-      JsonEncoder[Json].contramap {
-        case Empty              => Json.Obj.empty
-        case InitDiff(rendered) =>
-          Json.Obj(
-            "liveview_version" -> Json.Str("1.1.8"),
-            "rendered"         -> rendered.toJsonAST.getOrElse(throw new IllegalArgumentException())
-          )
-        case Diff(diff) =>
-          Json.Obj(
-            "diff" -> diff.toJsonAST.getOrElse(throw new IllegalArgumentException())
-          )
-      }
-end SocketMessage