handleWebSocketMessages

Signature

def handleWebSocketMessages(handler: Flow[Message, Message, Any]): Route

Description

The directive first checks if the request was a valid WebSocket handshake request and if yes, it completes the request with the passed handler. Otherwise, the request is rejected with an ExpectedWebSocketRequestRejection.

WebSocket subprotocols offered in the Sec-WebSocket-Protocol header of the request are ignored. If you want to support several protocols use the handleWebSocketMessagesForProtocol directive, instead.

For more information about the WebSocket support, see Server-Side WebSocket Support.

Example

def greeter: Flow[Message, Message, Any] =
  Flow[Message].mapConcat {
    case tm: TextMessage =>
      TextMessage(Source.single("Hello ") ++ tm.textStream ++ Source.single("!")) :: Nil
    case bm: BinaryMessage =>
      // ignore binary messages but drain content to avoid the stream being clogged
      bm.dataStream.runWith(Sink.ignore)
      Nil
  }
val websocketRoute =
  path("greeter") {
    handleWebSocketMessages(greeter)
  }

// tests:
// create a testing probe representing the client-side
val wsClient = WSProbe()

// WS creates a WebSocket request for testing
WS("/greeter", wsClient.flow) ~> websocketRoute ~>
  check {
    // check response for WS Upgrade headers
    isWebSocketUpgrade shouldEqual true

    // manually run a WS conversation
    wsClient.sendMessage("Peter")
    wsClient.expectMessage("Hello Peter!")

    wsClient.sendMessage(BinaryMessage(ByteString("abcdef")))
    wsClient.expectNoMessage(100.millis)

    wsClient.sendMessage("John")
    wsClient.expectMessage("Hello John!")

    wsClient.sendCompletion()
    wsClient.expectCompletion()
  }