在播放框架中关闭Twitter流连接

Question

I connect to twitter streaming API using Play 2.2 WS API in the code example below. I'm stuck trying to figure out how to disconnect from stream once it's established. Is there any proper way to do that rather than stopping application? Any help will be appreciated.

def watchTweets(keywords : String) = Action { implicit request =>
Logger.debug(s"watchTweets invoked with: $keywords")
val (tweetsOut, tweetChanel) = Concurrent.broadcast[JsValue]
WS.url(s"https://stream.twitter.com/1.1/statuses/filter.json?track=" + URLEncoder.encode(keywords, "UTF-8"))
  .sign(OAuthCalculator(Twitter.KEY, Twitter.sessionTokenPair.get))
  .postAndRetrieveStream("")(headers => Iteratee.foreach[Array[Byte]] { ba =>
  val msg = new String(ba, "UTF-8")
  Logger.debug(s"received message: $msg")
  val tweet = Json.parse(msg)
  tweetChanel.push(tweet)
}).flatMap(_.run)

Ok.chunked(tweetsOut &> Comet(callback = "parent.cometMessage")) }

Answer 1

This is a known issue... the answer is that you close the connection, but the problem is, the enumerator won't notice that the connection is closed until it tries to feed a tweet to the client, and that won't happen until it receives another tweet from Twitter, which might take a long time to happen.

This is of course a problem when doing Twitter streaming because Twitter will only let a user create one stream at a time, so that effectively means that you can't do a second stream until the first receives some data.

Unfortunately we don't have a work around as yet, but we are looking at introducing a new lower level streaming API into Play around the 2.4 time line, which will certainly allow this.