Wookiee - Component: Netty (HTTP)

Main Wookiee Project

For Configuration information see Netty Config

The Netty component provides both server http and websocket functionality using Netty.

For a working example see Wookiee - Netty Example

Config

wookiee-netty {
  manager = "com.webtrends.harness.component.netty.NettyManager"
  enabled = true

  # The port on which to run the server
  port = 9091
  # The URI to create a websocket connection
  websocket-path = "/stream"
  # The host name to set in HttpHeader
  server-header = "harness"
  # The time allowed to respond to a request
  request-timeout = 60s
  # The time after which an idle connection will be closed
  idle-timeout = 120s

  tcp {
    # Enables the TCP_NODELAY flag, i.e. disables Nagle.s algorithm
    tcp-nodelay = off
    # Enables TCP Keepalive, subject to the O/S kernel.s configuration
    tcp-keepalive = off
    # Sets the send buffer size of the Sockets,
    # set to 0b for platform default
    send-buffer-size = 0b
    # Sets the receive buffer size of the Sockets,
    # set to 0b for platform default
    receive-buffer-size = 0b
  }
}
akka.actor.deployment {
  /system/component/wookiee-netty/netty-server/netty-worker {
    router = round-robin-pool
    nr-of-instances = 3
  }
}

The configuration is fairly straight forward and you shouldn't need to modify it too much.

Netty Server

The server provides base http and websocket functionality. The user can customize this functionality by adding their own http handlers with websocket frame processing.

Adding an http handler

The primary function of having a http server is to allow requests to be made to your service and a subsequent response after some business logic is executed. For more information on building the handlers, see io.netty Documentation. To add a handler, you can do the following:

class MyHandler extends BaseInboundHandler {

  override def handleHttpRequest(ctx: ChannelHandlerContext, req: FullHttpRequest) : Boolean =  {
    var msgHandled = true
    
    (req.getMethod, req.getUri) match {
      case (GET, "/foo") =>
        val t = "".concat(new DateTime(System.currentTimeMillis(), DateTimeZone.UTC).toString)
        sendContent(ctx, req, s""" {"message": "myresponse", "time": "$t"} """, "application/json")
      case _ => msgHandled = false
    }
    
    msgHandled
  }
}

Adding TextWebSocketFrame processing

Providing custom websocket frame processing to your service can be done by overriding the WebSocketFrame function of the WebSocket trait and then adding it as a trait to your handler.

trait MyWebSocket extends WebSocket {

  override def WebSocketFrame(ctx: ChannelHandlerContext, frame: TextWebSocketFrame): Unit = {
    val request = frame.text()

    log.info(s"request: $request")
    ctx.writeAndFlush(new TextWebSocketFrame("Echo from example server: ".concat(request.toString)))
  }
}
...
new MyHandler with MyWebSocket
...