Re: [Lift] Comet chat stop working after a random time delay

[Matt Farmer]

Hi,

Can you set up a sample project on GitHub that I can clone and play with? This does seem curious… I’d like to take a peek at it and see if I can figure out what’s going on.

Thanks,

—
Matt Farmer | Blog | Twitter

On May 15, 2015, at 9:41 AM, Mirko Saiu <mirko...@gmail.com> wrote:

We have this kind of incomprehensible problem and we even don't know how exactly reproduce it. We just stop using the comet chat for a while keeping the web browser page open, then when we try to use the chat again , it doesn't works. It will works again only if you logout and login.

Jetty version is 8.1.17

Lift version is 2.6

Can someone help us?

Here some code..

The chat snippet:

class chatin extends Loggable {

  var message = ""

  var idExperience = S.param("key").map(_.toString) openOr("nudda")

  var meeting: Meeting = _

  var usr: User = _

  User.currentUser.map{ x =>

    usr = x

    meeting = Meeting.findByStringIdActive(idExperience).getOrElse{S.redirectTo("/404")}

    if (!meeting.belongsToUser(usr.id.toString())) S.redirectTo("/404")

    GMRConfig.sessionVars.last_meetingExp.set(idExperience)

    usr.last_meeting(idExperience).save

  } getOrElse({logger.error("Meeting, no user is logged")})

  def doSubmit() : JsCmd = {

    println("CHAT dosubmit 1")

    User.currentUser.map({ usr =>

      Meeting.findByStringId(idExperience).map({

        println("CHAT dosubmit 2 message: " + message)

        mp => mp.addChatMessage(usr, message)

      })

      SetValById("chat_in", "") & // clear the input box

        Call("scrollChat").cmd

    }) openOr {logger.error("user not logged in") }

  }

  def bindchat(xhtml: NodeSeq) = {

    var chatlist = <ul id="main_ul_id">

      <li id="main_li_id">

        <div name="fumetto">

          <img name="img" class="triang"/>

          <div name="body">

            {ChatMessage.where(_.meeting eqs GMRConfig.sessionVars.last_meetingExp.get).orderDesc(_.time).fetch.foreach(x=> line(x))}

          </div>

        </div>

        <div class="clear-both"></div>

      </li>

    </ul>

    var html =

      <div id="divChat" class="chat-box box" data-lift={"comet?type=Chat;name=" + idExperience + ";ul_id=main_ul_id;li_id=main_li_id"}>

        <div class="message-list">

          {chatlist}

        </div>

        <div class="form-input">

          <form class="lift:form.ajax">

            {SHtml.textarea("", message = _, "id" -> "chat_in")}

            {SHtml.ajaxSubmit(S.?("send"), doSubmit, "id" -> "send")}

          </form>

        </div>

      </div>

    bind("print", xhtml, "chat" -> html)

  }

  def line(c: ChatMessage) = {

    if (c.userEmail.get != User.currentUser.get.email.get){

      ("name=fumetto [class]" #> "fumetto-destinatario pull-left clear-both" &

        "name=img [src]" #> "/img/triang_conv_sx.png" &

        "name=body" #> c.message.get)

    }

    else{

      ( "name=fumetto [class]" #> "fumetto-mittente pull-right clear-both" &

        "name=img [src]" #> "/img/triang_conv_dx.png" &

        "name=body" #> c.message.get )

    }

  }

}

The CometActor and the LiftActor:

class Chat extends CometActor with CometListener with Loggable{

  private lazy val li = liId.flatMap(Helpers.findId(defaultHtml, _)) openOr NodeSeq.Empty

  private val ulId = S.attr("ul_id") openOr "some_ul_id"

  private val liId = S.attr("li_id")

  var meetingID = S.param("key").getOrElse("nudda")

  var chats: List[ChatMessage] =  ChatMessage.where(_.meeting eqs meetingID).orderDesc(_.time).fetch

  def updateChats(list: List[ChatMessage]) = {

      chats = list

  }

  override def exceptionHandler = {

    case e => logger.error(e.getStackTraceString)

  }

  override def lowPriority = {

    

    case x: ChatMessage => if(meetingID == x.meeting.get && !chats.contains(x)) {

      println("CHAT lowPriority: " + x.message.get)

      chats = x::chats

      val update = CmdPair(AppendHtml(ulId, line(x)),Call("scrollChat").cmd)

      partialUpdate(update)

    }

  }

  // register this component

  def registerWith = ChatServer

  // render the whole list of chats

  override def render = {

    ("#" + ulId + " *") #> {displayList}

  }

  // display a list of chats

  private def displayList: NodeSeq = chats.reverse.flatMap(line)

  // display a line

  private def line(c: ChatMessage) = {

    if (c.userEmail.is != User.currentUser.get.email.is){

      ("name=fumetto [class]" #> "fumetto-destinatario  pull-left clear-both" &

        "name=li [class]" #> "fumetto-sinistra  pull-right clear-both" &

        "name=img [src]" #> "/img/triang_conv_sx.png" &

        "name=body" #> c.message.is)(li)}

      else{

      ( "name=fumetto [class]" #> "fumetto-mittente  pull-right clear-both" &

        "name=li [class]" #> "fumetto-destra  pull-right clear-both" &

        "name=img [src]" #> "/img/triang_conv_dx.png" &

        "name=body" #> c.message.is)(li)

    }

  }

}

object ChatServer extends LiftActor with ListenerManager with Loggable{

  //variablie che viene aggiornata aad ogni meering page aperta

 var chat: ChatMessage = _

  override protected def exceptionHandler = {

    case e => logger.error(e.getStackTraceString)

  }

  override def lowPriority = {

    case v: ChatMessage  =>

      chat = v

      updateListeners()

    case _ =>

  }

  def createUpdate = chat

  def toHtml(msg: String): NodeSeq = <div>{msg}</div>

}

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[Mirko Saiu]

Ok, we tried any kind of solution, from updating jetty and lift framework to changing the server memory configuration and go on.. at the end the solution was very much simpler. 

We had the html annidated like this:

<div data-lift="Snippet1">
   
   <div data-lift="ChatSnippet"></div>

</div>


We resolved doing this:

<div data-lift="ChatSnippet"></div>

<div data-lift="Snippet1"></div>


Very simple