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c# socket心跳超時(shí)檢測(cè)的思路(適用于超大量TCP連接情況下)

 更新時(shí)間：2021年03月08日 11:59:34   作者：源之緣  
這篇文章主要介紹了c# socket心跳超時(shí)檢測(cè)的思路(適用于超大量TCP連接情況下)，幫助大家更好的理解和學(xué)習(xí)使用c#，感興趣的朋友可以了解下

假設(shè)一種情景：

TCP服務(wù)器有1萬(wàn)個(gè)客戶(hù)端連接，如果客戶(hù)端5秒鐘不發(fā)數(shù)據(jù)，則要斷開(kāi)。服務(wù)端如何檢測(cè)客戶(hù)端是否超時(shí)？這看起來(lái)是一個(gè)非常簡(jiǎn)單的問(wèn)題，其實(shí)不然！

最簡(jiǎn)單的處理方法是：

啟動(dòng)一個(gè)線(xiàn)程，每隔一段時(shí)間，檢查每個(gè)連接是否超時(shí)。每次處理需要1萬(wàn)次檢查。計(jì)算量太大！檢查的時(shí)間間隔不能太小，否則大大增加計(jì)算量；如果間隔時(shí)間太大，超時(shí)誤差會(huì)增大。

本文提出一種新穎的處理方法，就是針對(duì)這個(gè)看似簡(jiǎn)單而不易解決的問(wèn)題?。ㄒ韵掠胹ocket表示一個(gè)客戶(hù)端連接）

1 內(nèi)存布局圖

假設(shè)socket3有新的數(shù)據(jù)到達(dá)，需要更新socket3所在的時(shí)間軸，處理邏輯如下：

2 處理過(guò)程分析：

基本的處理思路就是增加時(shí)間軸概念。將socket按最后更新時(shí)間排序。因?yàn)闀r(shí)間是連續(xù)的，不可能將時(shí)間分割太細(xì)。首先將時(shí)間離散，比如屬于同一秒內(nèi)的更新，被認(rèn)為是屬于同一個(gè)時(shí)間點(diǎn)。離散的時(shí)間間隔稱(chēng)為時(shí)間刻度，該刻度值可以根據(jù)具體情況調(diào)整?？潭戎翟叫?，超時(shí)計(jì)算越精確；但是計(jì)算量增大。如果時(shí)間刻度為10毫秒，則一秒的時(shí)間長(zhǎng)度被劃分為100份。所以需要對(duì)更新時(shí)間做規(guī)整，代碼如下：

DateTime CreateNow()
 {
  DateTime now = DateTime.Now;
  int m = 0; 
  if(now.Millisecond != 0)
  {
  if(_minimumScaleOfMillisecond == 1000)
  {
   now = now.AddSeconds(1); //尾數(shù)加1，確保超時(shí)值大于 給定的值
  }
  else
  {
   //如果now.Millisecond為16毫秒，精確度為10毫秒。則轉(zhuǎn)換后為20毫秒
   m = now.Millisecond - now.Millisecond % _minimumScaleOfMillisecond + _minimumScaleOfMillisecond;
   if(m>=1000)
   {
   m -= 1000;
   now = now.AddSeconds(1);
   }
  }
  }
  return new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, now.Second,m);
 }

屬于同一個(gè)時(shí)間刻度的socket，被放入在一個(gè)哈希表中（見(jiàn)圖中Group）。存放socket的類(lèi)如下：

class SameTimeKeyGroup<T>
 {
 DateTime _timeStamp;
 public DateTime TimeStamp => _timeStamp;
 public SameTimeKeyGroup(DateTime time)
 {
  _timeStamp = time;
 }
 public HashSet<T> KeyGroup { get; set; } = new HashSet<T>();

 public bool ContainKey(T key)
 {
  return KeyGroup.Contains(key);
 }

 internal void AddKey(T key)
 {
  KeyGroup.Add(key);
 }
 internal bool RemoveKey(T key)
 {
  return KeyGroup.Remove(key);
 }
 }

 定義一個(gè)List表示時(shí)間軸：

List<SameTimeKeyGroup<T>> _listTimeScale = new List<SameTimeKeyGroup<T>>();

 在_listTimeScale 前端的時(shí)間較舊，所以鏈表前端就是有可能超時(shí)的socket。

當(dāng)有socket需要更新時(shí)，需要快速知道socket所在的group。這樣才能將socket從舊的group移走，再添加到新的group中。需要新增一個(gè)鏈表：

 Dictionary<T, SameTimeKeyGroup<T>> _socketToSameTimeKeyGroup = new Dictionary<T, SameTimeKeyGroup<T>>();

2.1 當(dāng)socket有新的數(shù)據(jù)到達(dá)時(shí)，處理步驟：

  • 查找socket的上一個(gè)群組。如果該群組對(duì)應(yīng)的時(shí)刻和當(dāng)前時(shí)刻相同（時(shí)間都已經(jīng)離散，才有可能相同），無(wú)需更新時(shí)間軸。
  • 從舊的群組刪除，增加到新的群組。
public void UpdateTime(T key)
 {
  DateTime now = CreateNow();
  //是否已存在,從上一個(gè)時(shí)間群組刪除
  if (_socketToSameTimeKeyGroup.ContainsKey(key))
  {
  SameTimeKeyGroup<T> group = _socketToSameTimeKeyGroup[key];
  if (group.ContainKey(key))
  {
   if (group.TimeStamp == now) //同一時(shí)間更新，無(wú)需移動(dòng)
   {
   return;
   }
   else
   {
   group.RemoveKey(key);
   _socketToSameTimeKeyGroup.Remove(key);
   }
  }
  }

  //從超時(shí)組 刪除
  _timeoutSocketGroup.Remove(key);

  //加入到新組
  SameTimeKeyGroup<T> groupFromScaleList = GetOrCreateSocketGroup(now, out bool newCreate);
  groupFromScaleList.AddKey(key);

  _socketToSameTimeKeyGroup.Add(key, groupFromScaleList);

  if (newCreate)
  {
  AdjustTimeout();
  }
 }

2.2 獲取超時(shí)的socket

 時(shí)間軸從舊到新，對(duì)比群組的時(shí)間與超時(shí)時(shí)刻。就是鏈表_listTimeScale，從0開(kāi)始查找。

/// <summary>
 ///timeLimit 值為超時(shí)時(shí)刻限制 
 ///比如DateTime.Now.AddMilliseconds(-1000);表示 返回一秒鐘以前的數(shù)據(jù)
 /// </summary>
 /// <param name="timeLimit">該時(shí)間以前的socket會(huì)被返回</param>
 /// <returns></returns>
 public List<T> GetTimeoutValue(DateTime timeLimit, bool remove = true)
 {
  if((DateTime.Now - timeLimit) > _maxSpan )
  {
  Debug.Write("GetTimeoutSocket timeLimit 參數(shù)有誤！");
  }

  //從超時(shí)組 讀取
  List<T> result = new List<T>();
  foreach(T key in _timeoutSocketGroup)
  {
  _timeoutSocketGroup.Add(key);
  }

  if(remove)
  {
  _timeoutSocketGroup.Clear();
  }

  while (_listTimeScale.Count > 0)
  {
  //時(shí)間軸從舊到新，查找對(duì)比
  SameTimeKeyGroup<T> group = _listTimeScale[0];
  if(timeLimit >= group.TimeStamp)
  {
   foreach (T key in group.KeyGroup)
   {
   result.Add(key);
   if (remove)
   {
    _socketToSameTimeKeyGroup.Remove(key);
   }
   }

   if(remove)
   {
   _listTimeScale.RemoveAt(0);
   }
  }
  else
  {
   break;
  }
  }

  return result;
 }

3 使用舉例

//創(chuàng)建變量。最大超時(shí)時(shí)間為600秒，時(shí)間刻度為1秒
TimeSpanManage<Socket> _deviceActiveManage = TimeSpanManage<Socket>.Create(TimeSpan.FromSeconds(600), 1000);

//當(dāng)有數(shù)據(jù)到達(dá)時(shí)，調(diào)用更新函數(shù) 
_deviceActiveManage.UpdateTime(socket);

//需要在線(xiàn)程或定時(shí)器中，每隔一段時(shí)間調(diào)用，找出超時(shí)的socket
//找出超時(shí)時(shí)間超過(guò)600秒的socket。
foreach (Socket socket in _deviceActiveManage.GetTimeoutValue(DateTime.Now.AddSeconds(-600)))
{
 socket.Close();
}

4 完整代碼

/// <summary>
 /// 超時(shí)時(shí)間 時(shí)間間隔處理
 /// </summary>
 class TimeSpanManage<T>
 {
 TimeSpan _maxSpan;
 int _minimumScaleOfMillisecond;
 int _scaleCount;

 List<SameTimeKeyGroup<T>> _listTimeScale = new List<SameTimeKeyGroup<T>>();
 private TimeSpanManage()
 {
 }

 /// <summary>
 ///
 /// </summary>
 /// <param name="maxSpan">最大時(shí)間時(shí)間</param>
 /// <param name="minimumScaleOfMillisecond">最小刻度（毫秒）</param>
 /// <returns></returns>
 public static TimeSpanManage<T> Create(TimeSpan maxSpan, int minimumScaleOfMillisecond)
 {
  if (minimumScaleOfMillisecond <= 0)
  throw new Exception("minimumScaleOfMillisecond 小于0");
  if (minimumScaleOfMillisecond > 1000)
  throw new Exception("minimumScaleOfMillisecond 不能大于1000");

  if (maxSpan.TotalMilliseconds <= 0)
  throw new Exception("maxSpan.TotalMilliseconds 小于0");

  TimeSpanManage<T> result = new TimeSpanManage<T>();
  result._maxSpan = maxSpan;
  result._minimumScaleOfMillisecond = minimumScaleOfMillisecond;

  result._scaleCount = (int)(maxSpan.TotalMilliseconds / minimumScaleOfMillisecond);
  result._scaleCount++;
  return result;
 }

 Dictionary<T, SameTimeKeyGroup<T>> _socketToSameTimeKeyGroup = new Dictionary<T, SameTimeKeyGroup<T>>();
 public void UpdateTime(T key)
 {
  DateTime now = CreateNow();
  //是否已存在,從上一個(gè)時(shí)間群組刪除
  if (_socketToSameTimeKeyGroup.ContainsKey(key))
  {
  SameTimeKeyGroup<T> group = _socketToSameTimeKeyGroup[key];
  if (group.ContainKey(key))
  {
   if (group.TimeStamp == now) //同一時(shí)間更新，無(wú)需移動(dòng)
   {
   return;
   }
   else
   {
   group.RemoveKey(key);
   _socketToSameTimeKeyGroup.Remove(key);
   }
  }
  }

  //從超時(shí)組 刪除
  _timeoutSocketGroup.Remove(key);

  //加入到新組
  SameTimeKeyGroup<T> groupFromScaleList = GetOrCreateSocketGroup(now, out bool newCreate);
  groupFromScaleList.AddKey(key);

  _socketToSameTimeKeyGroup.Add(key, groupFromScaleList);

  if (newCreate)
  {
  AdjustTimeout();
  }
 }

 public bool RemoveSocket(T key)
 {
  bool result = false;
  if (_socketToSameTimeKeyGroup.ContainsKey(key))
  {
  SameTimeKeyGroup<T> group = _socketToSameTimeKeyGroup[key];
  result = group.RemoveKey(key);

  _socketToSameTimeKeyGroup.Remove(key);
  }

  //從超時(shí)組 刪除
  bool result2 = _timeoutSocketGroup.Remove(key);
  return result || result2;
 }

 /// <summary>
 ///timeLimit 值為超時(shí)時(shí)刻限制
 ///比如DateTime.Now.AddMilliseconds(-1000);表示 返回一秒鐘以前的數(shù)據(jù)
 /// </summary>
 /// <param name="timeLimit">該時(shí)間以前的socket會(huì)被返回</param>
 /// <returns></returns>
 public List<T> GetTimeoutValue(DateTime timeLimit, bool remove = true)
 {
  if((DateTime.Now - timeLimit) > _maxSpan )
  {
  Debug.Write("GetTimeoutSocket timeLimit 參數(shù)有誤！");
  }

  //從超時(shí)組 讀取
  List<T> result = new List<T>();
  foreach(T key in _timeoutSocketGroup)
  {
  _timeoutSocketGroup.Add(key);
  }

  if(remove)
  {
  _timeoutSocketGroup.Clear();
  }

  while (_listTimeScale.Count > 0)
  {
  //時(shí)間軸從舊到新，查找對(duì)比
  SameTimeKeyGroup<T> group = _listTimeScale[0];
  if(timeLimit >= group.TimeStamp)
  {
   foreach (T key in group.KeyGroup)
   {
   result.Add(key);
   if (remove)
   {
    _socketToSameTimeKeyGroup.Remove(key);
   }
   }

   if(remove)
   {
   _listTimeScale.RemoveAt(0);
   }
  }
  else
  {
   break;
  }
  }

  return result;
 }

 HashSet<T> _timeoutSocketGroup = new HashSet<T>();
 private void AdjustTimeout()
 {
  while (_listTimeScale.Count > _scaleCount)
  {
  SameTimeKeyGroup<T> group = _listTimeScale[0];
  foreach (T key in group.KeyGroup)
  {
   _timeoutSocketGroup.Add(key);
  }

  _listTimeScale.RemoveAt(0);
  }
 }

 private SameTimeKeyGroup<T> GetOrCreateSocketGroup(DateTime now, out bool newCreate)
 {
  if (_listTimeScale.Count == 0)
  {
  newCreate = true;
  SameTimeKeyGroup<T> result = new SameTimeKeyGroup<T>(now);
  _listTimeScale.Add(result);
  return result;
  }
  else
  {
  SameTimeKeyGroup<T> lastGroup = _listTimeScale[_listTimeScale.Count - 1];
  if (lastGroup.TimeStamp == now)
  {
   newCreate = false;
   return lastGroup;
  }

  newCreate = true;
  SameTimeKeyGroup<T> result = new SameTimeKeyGroup<T>(now);
  _listTimeScale.Add(result);
  return result;
  }
 }

 DateTime CreateNow()
 {
  DateTime now = DateTime.Now;
  int m = 0;
  if(now.Millisecond != 0)
  {
  if(_minimumScaleOfMillisecond == 1000)
  {
   now = now.AddSeconds(1); //尾數(shù)加1，確保超時(shí)值大于 給定的值
  }
  else
  {
   //如果now.Millisecond為16毫秒，精確度為10毫秒。則轉(zhuǎn)換后為20毫秒
   m = now.Millisecond - now.Millisecond % _minimumScaleOfMillisecond + _minimumScaleOfMillisecond;
   if(m>=1000)
   {
   m -= 1000;
   now = now.AddSeconds(1);
   }
  }
  }
  return new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, now.Second,m);
 }
 }

 class SameTimeKeyGroup<T>
 {
 DateTime _timeStamp;
 public DateTime TimeStamp => _timeStamp;
 public SameTimeKeyGroup(DateTime time)
 {
  _timeStamp = time;
 }
 public HashSet<T> KeyGroup { get; set; } = new HashSet<T>();

 public bool ContainKey(T key)
 {
  return KeyGroup.Contains(key);
 }

 internal void AddKey(T key)
 {
  KeyGroup.Add(key);
 }
 internal bool RemoveKey(T key)
 {
  return KeyGroup.Remove(key);
 }
 }

以上就是c# socket心跳超時(shí)檢測(cè)的思路(適用于超大量TCP連接情況下)的詳細(xì)內(nèi)容，更多關(guān)于c# socket心跳超時(shí)檢測(cè)的資料請(qǐng)關(guān)注腳本之家其它相關(guān)文章！

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