sttp.client3.httpclient.WebSocketImpl.scala Maven / Gradle / Ivy

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package sttp.client3.httpclient

import sttp.client3.internal._
import sttp.client3.internal.ws.{SimpleQueue, WebSocketEvent}
import sttp.model.Headers
import sttp.monad.syntax._
import sttp.monad.{Canceler, MonadAsyncError, MonadError}
import sttp.ws.{WebSocket, WebSocketClosed, WebSocketFrame}

import java.net.http.WebSocket.Listener
import java.net.http.{WebSocket => JWebSocket}
import java.nio.ByteBuffer
import java.util.concurrent.atomic.AtomicBoolean
import java.util.concurrent.{CompletableFuture, CompletionStage}
import java.util.function.BiConsumer

private[httpclient] class WebSocketImpl[F[_]](
    ws: JWebSocket,
    queue: SimpleQueue[F, WebSocketEvent],
    _isOpen: AtomicBoolean,
    _monad: MonadAsyncError[F],
    sequencer: Sequencer[F]
) extends WebSocket[F] {
  override def receive(): F[WebSocketFrame] = {
    queue.poll.flatMap {
      case WebSocketEvent.Open() => receive()
      case WebSocketEvent.Frame(c: WebSocketFrame.Close) =>
        queue.offer(WebSocketEvent.Error(WebSocketClosed(Some(c))))
        monad.unit(c)
      case e @ WebSocketEvent.Error(t: Exception) =>
        // putting back the error so that subsequent invocations end in an error as well, instead of hanging
        queue.offer(e)
        monad.error(t)
      case WebSocketEvent.Error(t) => throw t
      case WebSocketEvent.Frame(f: WebSocketFrame) =>
        monad.eval {
          ws.request(1)
          f
        }
    }
  }

  override def send(f: WebSocketFrame, isContinuation: Boolean = false): F[Unit] = {
    // ws.send* is not thread-safe - at least one can run at a time. Hence, adding a sequencer to ensure that
    // even if called concurrently, these will be run in sequence.
    sequencer(monad.flatten(monad.eval {
      f match {
        case WebSocketFrame.Text(payload, finalFragment, _) =>
          fromCompletableFuture(ws.sendText(payload, finalFragment))
        case WebSocketFrame.Binary(payload, finalFragment, _) =>
          fromCompletableFuture(ws.sendBinary(ByteBuffer.wrap(payload), finalFragment))
        case WebSocketFrame.Ping(payload) => fromCompletableFuture(ws.sendPing(ByteBuffer.wrap(payload)))
        case WebSocketFrame.Pong(payload) => fromCompletableFuture(ws.sendPong(ByteBuffer.wrap(payload)))
        case WebSocketFrame.Close(statusCode, reasonText) =>
          val wasOpen = _isOpen.getAndSet(false)
          // making close sequentially idempotent
          if (wasOpen) fromCompletableFuture(ws.sendClose(statusCode, reasonText)) else ().unit
      }
    }))
  }

  override lazy val upgradeHeaders: Headers = Headers(Nil)

  override def isOpen(): F[Boolean] = monad.eval(_isOpen.get())

  override implicit def monad: MonadError[F] = _monad

  private def fromCompletableFuture(cf: CompletableFuture[JWebSocket]): F[Unit] = {
    _monad.async { cb =>
      cf.whenComplete(new BiConsumer[JWebSocket, Throwable] {
        override def accept(t: JWebSocket, error: Throwable): Unit = {
          if (error != null) {
            cb(Left(error))
          } else {
            cb(Right(()))
          }
        }
      })
      Canceler { () =>
        cf.cancel(true)
        ()
      }
    }
  }
}

private[httpclient] class AddToQueueListener[F[_]](
    queue: SimpleQueue[F, WebSocketEvent],
    isOpen: AtomicBoolean
) extends Listener {
  override def onOpen(webSocket: JWebSocket): Unit = {
    isOpen.set(true)
    queue.offer(WebSocketEvent.Open())
    webSocket.request(1)
  }

  override def onText(webSocket: JWebSocket, data: CharSequence, last: Boolean): CompletionStage[_] = {
    onFrame(WebSocketFrame.Text(data.toString, last, None))
    null
  }

  override def onBinary(webSocket: JWebSocket, data: ByteBuffer, last: Boolean): CompletionStage[_] = {
    onFrame(WebSocketFrame.Binary(data.safeRead(), last, None))
    null
  }

  override def onPing(webSocket: JWebSocket, message: ByteBuffer): CompletionStage[_] = {
    onFrame(WebSocketFrame.Ping(message.array()))
    null
  }

  override def onPong(webSocket: JWebSocket, message: ByteBuffer): CompletionStage[_] = {
    onFrame(WebSocketFrame.Pong(message.array()))
    null
  }

  override def onClose(webSocket: JWebSocket, statusCode: Int, reason: String): CompletionStage[_] = {
    isOpen.set(false)
    queue.offer(WebSocketEvent.Frame(WebSocketFrame.Close(statusCode, reason)))
    super.onClose(webSocket, statusCode, reason)
  }

  override def onError(webSocket: JWebSocket, error: Throwable): Unit = {
    isOpen.set(false)
    queue.offer(WebSocketEvent.Error(error))
    super.onError(webSocket, error)
  }

  private def onFrame(f: WebSocketFrame): Unit = queue.offer(WebSocketEvent.Frame(f))
}