replace ServerRegistration#unfurlSrv to DNSResolver class

lib/servers.js

@@ -1,6 +1,6 @@
 const crypto = require('crypto')
-const dns = require('dns')
 
+const DNSResolver = require('./dns')
 const TimeTracker = require('./time')
 const Server = require('./server')
 
@@ -18,6 +18,7 @@ class ServerRegistration {
     this.serverId = serverId
     this.data = data
     this._pingHistory = []
+    this.dnsResolver = new DNSResolver(this.data.ip, this.data.port)
   }
 
   handlePing (timestamp, resp, err, version) {
@@ -310,62 +311,6 @@ class ServerRegistration {
       color: this.data.color
     }
   }
-
-  unfurlSrv (callback) {
-    // Skip unfurling SRV, instantly return pre-configured data
-    if (config.performance && config.performance.skipUnfurlSrv) {
-      callback(this.data.ip, this.data.port)
-      return
-    }
-
-    const timestamp = new Date().getTime()
-
-    // If a cached copy exists and is within its TTL, instantly return
-    if (this._lastUnfurlSrv && timestamp - this._lastUnfurlSrv.timestamp <= config.performance.unfurlSrvCacheTtl) {
-      callback(this._lastUnfurlSrv.ip, this._lastUnfurlSrv.port)
-      return
-    }
-
-    // Group callbacks into an array
-    // Once resolved, fire callbacks sequentially
-    // This avoids callbacks possibly executing out of order
-    if (!this._unfurlSrvCallbackQueue) {
-      this._unfurlSrvCallbackQueue = []
-    }
-
-    this._unfurlSrvCallbackQueue.push(callback)
-
-    // Prevent multiple #resolveSrv calls per ServerRegistration
-    if (!this._isUnfurlingSrv) {
-      this._isUnfurlingSrv = true
-
-      dns.resolveSrv('_minecraft._tcp.' + this.data.ip, (_, records) => {
-        this._lastUnfurlSrv = {
-          timestamp
-        }
-
-        if (records && records.length > 0) {
-          this._lastUnfurlSrv.ip = records[0].name
-          this._lastUnfurlSrv.port = records[0].port
-        } else {
-          // Provide fallback to pre-configured data
-          this._lastUnfurlSrv.ip = this.data.ip
-          this._lastUnfurlSrv.port = this.data.port
-        }
-
-        // Fire the waiting callbacks in queue
-        // Release blocking flag to allow new #resolveSrv calls
-        this._isUnfurlingSrv = false
-
-        for (const callback of this._unfurlSrvCallbackQueue) {
-          callback(this._lastUnfurlSrv.ip, this._lastUnfurlSrv.port)
-        }
-
-        // Reset the callback queue
-        this._unfurlSrvCallbackQueue = []
-      })
-    }
-  }
 }
 
 module.exports = ServerRegistration