我目前正在尝试使用可用的RTM API使用Scala创建一个#slack bot。
我已经设法得到一个基本的功能机器人，响应"ping"与"pong"。
我目前遇到的问题是，websocket连接在打开流后每隔几分钟系统地关闭一次。
我目前使用以下库的websockets: https://github.com/jfarcand/WCS
在这一点上，我不完全确定是什么原因导致从#slack RTM流接收到的空JSON消息({})之后的连接下降。
任何帮助都将是非常感激的。
下面是相关的连接和侦听器代码:
def connect(): Unit ={
if(rec_url == "")
slack = ws.open(rtm_url)
else {
h.debug("Attempting to reconnect")
slack = WebSocket().open(rec_url) // TODO: need to completely close the connection before trying to create a new one.
}
initRTM()
}
// Initialize Real Time Messaging
def initRTM(): Unit = {
h.debug("nOpening Real Time Messaging socket")
slack.listener(new TextListener {
override def onOpen: Unit = {
h.debug("Websocket connection open")
status = 1
}
override def onClose: Unit = {
h.debug("Websocket connection closed, reconnecting...")
slack.shutDown
status = 0
}
override def onError(t: Throwable): Unit ={
h.debug("Websocket Error encountered")
t.printStackTrace()
h.debug(t.getMessage)
}
override def onMessage(message: String) {
h.debug("Message received: "+message)
val body: JsValue = Json.parse(message)
try {
if(body.as[JsObject].keys.contains("type")){
val m_type = (body "type").as[String]
m_type match {
case "hello" => ;
case "reconnect_url" => setReconnectUrl((body "url").as[String])
case "message" => processMessage(body)
case _ => h.debug("Unprocessed message type: " + m_type)
}
}
} catch {
case e: Exception=> e.printStackTrace()
}
}
})
while(slack.isOpen){
}
h.debug("connection is closed")
connect()
}
下面是控制台的输出:
Opening Real Time Messaging socket
INFO - Websocket connection open
INFO - Message received: {"type":"hello"}
INFO - Message received: {"reply_to":0,"type":"message","channel":"D1NCSAU12","user":"U1NCSAU0L","text":"pong","ts":"1467558776.000079"}
INFO - Message received: {"type":"reconnect_url","url":"wss://mpmulti-c6k1.slack-msgs.com/websocket/x4UkvMwZeNqFuyZ_YsxjLNi_OIOzqHisL6sHC3DB0QRnKoG-VH8Qr361SlSprlWb6WjzDhw6j5Pj0FiFFYTjoiCLwM-i863os0xWkjUGJJbUoKUmtlG22e3lTTAFuuIFg2TTI7W-0XfU4HJB2nvbjy_hKCwVQ7uIIlrr6fYi_ms="}
INFO - Reconnect URL Set to: wss://mpmulti-c6k1.slack-msgs.com/websocket/x4UkvMwZeNqFuyZ_YsxjLNi_OIOzqHisL6sHC3DB0QRnKoG-VH8Qr361SlSprlWb6WjzDhw6j5Pj0FiFFYTjoiCLwM-i863os0xWkjUGJJbUoKUmtlG22e3lTTAFuuIFg2TTI7W-0XfU4HJB2nvbjy_hKCwVQ7uIIlrr6fYi_ms=
INFO - Message received: {"type":"presence_change","presence":"active","user":"U1NCSAU0L"}
INFO - Unprocessed message type: presence_change
11:23:18.790 [Hashed wheel timer #1] DEBUG com.ning.http.client.providers.netty.channel.pool.DefaultChannelPool - Closed 0 connections out of 0 in 0ms
INFO - Message received: {"type":"user_typing","channel":"D1NCSAU12","user":"U1MP4A19R"}
INFO - Unprocessed message type: user_typing
INFO - Message received: {"type":"message","channel":"D1NCSAU12","user":"U1MP4A19R","text":"ping","ts":"1467559430.000080","team":"T1MQWNFR8"}
INFO - User typed 'ping'
INFO - Answer: {"id":0,"type":"message","channel":"D1NCSAU12","text":"pong"}
INFO - Message received: {"ok":true,"reply_to":0,"ts":"1467559430.000081","text":"pong"}
INFO - Message received: {"type":"user_typing","channel":"D1NCSAU12","user":"U1MP4A19R"}
INFO - Unprocessed message type: user_typing
INFO - Message received: {"type":"message","channel":"D1NCSAU12","user":"U1MP4A19R","text":"ping","ts":"1467559432.000082","team":"T1MQWNFR8"}
INFO - User typed 'ping'
INFO - Answer: {"id":1,"type":"message","channel":"D1NCSAU12","text":"pong"}
INFO - Message received: {"ok":true,"reply_to":1,"ts":"1467559432.000083","text":"pong"}
INFO - Message received: {"type":"user_typing","channel":"D1NCSAU12","user":"U1MP4A19R"}
INFO - Unprocessed message type: user_typing
INFO - Message received: {"type":"message","channel":"D1NCSAU12","user":"U1MP4A19R","text":"ping","ts":"1467559434.000084","team":"T1MQWNFR8"}
INFO - User typed 'ping'
INFO - Answer: {"id":2,"type":"message","channel":"D1NCSAU12","text":"pong"}
INFO - Message received: {"ok":true,"reply_to":2,"ts":"1467559434.000085","text":"pong"}
INFO - Message received: {"type":"user_typing","channel":"D1NCSAU12","user":"U1MP4A19R"}
INFO - Unprocessed message type: user_typing
INFO - Message received: {"type":"message","channel":"D1NCSAU12","user":"U1MP4A19R","text":"ping","ts":"1467559448.000086","team":"T1MQWNFR8"}
INFO - User typed 'ping'
INFO - Answer: {"id":3,"type":"message","channel":"D1NCSAU12","text":"pong"}
INFO - Message received: {"ok":true,"reply_to":3,"ts":"1467559448.000087","text":"pong"}
INFO - Message received: {"type":"user_typing","channel":"D1NCSAU12","user":"U1MP4A19R"}
INFO - Unprocessed message type: user_typing
INFO - Message received: {"type":"message","channel":"D1NCSAU12","user":"U1MP4A19R","text":"ping ping","ts":"1467559452.000088","team":"T1MQWNFR8"}
11:24:18.889 [Hashed wheel timer #1] DEBUG com.ning.http.client.providers.netty.channel.pool.DefaultChannelPool - Closed 0 connections out of 0 in 0ms
INFO - Message received: {"type":"reconnect_url","url":"wss://mpmulti-lbww.slack-msgs.com/websocket/u61Fem7nt3c1DP35C1So6S-Q3QnP0wcY4BeKMG6GZBpjo32E_rGM0YhwH-M_i6uGdezSgzr8R6BmM4eC7ZcwGaAR38GRi2VFyEM7REgtCO0Hd6FAsguHS63TwCI65UwBCkcS_gEFdpoI5tD0az4cBWtdfj1yXbn1iOwpiH_BALg="}
INFO - Reconnect URL Set to: wss://mpmulti-lbww.slack-msgs.com/websocket/u61Fem7nt3c1DP35C1So6S-Q3QnP0wcY4BeKMG6GZBpjo32E_rGM0YhwH-M_i6uGdezSgzr8R6BmM4eC7ZcwGaAR38GRi2VFyEM7REgtCO0Hd6FAsguHS63TwCI65UwBCkcS_gEFdpoI5tD0az4cBWtdfj1yXbn1iOwpiH_BALg=
11:25:18.989 [Hashed wheel timer #1] DEBUG com.ning.http.client.providers.netty.channel.pool.DefaultChannelPool - Closed 0 connections out of 0 in 0ms
INFO - Message received: {}
11:26:13.918 [New I/O worker #1] DEBUG com.ning.http.client.providers.netty.handler.Processor - Channel Closed: [id: 0x0e0d06c0, /192.168.99.102:46345 :> mpmulti-6wbl.slack-msgs.com/54.172.207.190:443] with attribute NettyResponseFuture{currentRetry=5,
isDone=true,
isCancelled=false,
asyncHandler=com.ning.http.client.ws.WebSocketUpgradeHandler@e9cba57,
nettyRequest=com.ning.http.client.providers.netty.request.NettyRequest@b3f8453,
content=NettyWebSocket{channel=[id: 0x0e0d06c0, /192.168.99.102:46345 :> mpmulti-6wbl.slack-msgs.com/54.172.207.190:443]},
uri=wss://mpmulti-6wbl.slack-msgs.com/websocket/0WNxIQsK_mzw561vkxWrN4B3tSPO-oBBR6fPtGnD2GLP_47Cms8s8GzyNl8ujheXVnNIw0RygTwglxlZYdfChlNf_0MfCwihOeQMUI-hjgCcwxXuMZFUSYrZphQpu1w7VYP5j3dc0nOVnL0YZX_oi62cgeoaWgwn5GjUiif-0AM=,
keepAlive=true,
httpHeaders=org.jboss.netty.handler.codec.http.DefaultHttpHeaders@790add3d,
exEx=null,
redirectCount=0,
timeoutsHolder=null,
inAuth=false,
statusReceived=false,
touch=530188604}
INFO - Websocket connection closed, reconnecting...
11:26:13.920 [New I/O worker #1] DEBUG com.ning.http.client.providers.netty.channel.ChannelManager - Closing Channel [id: 0x0e0d06c0, /192.168.99.102:46345 :> mpmulti-6wbl.slack-msgs.com/54.172.207.190:443]
在对这个问题做了一些额外的研究并尝试了各种方法之后，我已经尽我所能解决了这个问题。
似乎#slack API需要定期发送ping消息，以防止连接被丢弃。
随着计时器代码的实现，每30秒发送一个ping消息，到目前为止，我不再遇到这个问题。
下面是我为了解决这个问题而添加的代码的一部分:
def initRTM(): Unit = {
h.debug("nOpening Real Time Messaging socket")
h.debug("Pinging at 30s intervals")
val ex = new ScheduledThreadPoolExecutor(1)
val task = new Runnable {
def run() = sendPing()
}
val f = ex.scheduleAtFixedRate(task, 1, 30, TimeUnit.SECONDS)
if(!slack.isOpen){
f.cancel(false)
}
[...]
}
RTM API (https://api.slack.com/rtm)没有特别说明发送ping消息是保持连接存活的强制条件，但强烈建议这样做:
客户端应该尝试快速检测断开连接，即使在空闲时句号，这样用户可以很容易地分辨出两者的区别没有联系，每个人都很安静。并不是所有的浏览器都支持WebSocket ping规范，所以RTM协议也支持ping/pong消息。当没有其他活动时，客户端应该发送一个ping每隔几秒
这实际上似乎是为了保持连接存活的必要条件。
我希望这有助于其他用户在接近#slack RTM API时遇到类似的问题。