5
這是情況。可以使用收益率返回「現場」JSON嗎？
我所用的工作： - ASP.NET MVC 4的Web API - IIS 7.0託管應用 - C＃
我的Web API，它得到Intranet上的和正在測試來自遠程計算機的性能數據通過URL調用調用API，並返回JSON。但是，它必須在返回JSON之前先完成執行。例如，如果我將性能監視返回10秒，則必須等待10秒才能顯示所有數據值。
我想要做的就是實時獲取它，以便它在每秒鐘讀取性能計數器並以JSON顯示時返回一個值，而不是等待所有要檢索的內容，然後一次列出。我正在嘗試使用YIELD關鍵字來完成此操作，但它仍然無法正常工作。在該方法完全結束之前，JSON不會顯示在瀏覽器中。
下面是倉庫方法和協調控制器動作的代碼：
從LogDBRepository.cs：
public IEnumerable<DataValueInfo> LogTimedPerfDataLive(string macName, string categoryName, string counterName,
string instanceName, string logName, long? seconds)
{
iModsDBRepository modsDB = new iModsDBRepository();
List<MachineInfo> theMac = modsDB.GetMachineByName(macName);
if (theMac.Count == 0)
yield break;
else if (instanceName == null)
{
if (!PerformanceCounterCategory.Exists(categoryName, macName) ||
!PerformanceCounterCategory.CounterExists(counterName, categoryName, macName))
{
yield break;
}
}
else if (instanceName != null)
{
if (!PerformanceCounterCategory.Exists(categoryName, macName) ||
!PerformanceCounterCategory.CounterExists(counterName, categoryName, macName) ||
!PerformanceCounterCategory.InstanceExists(instanceName, categoryName, macName))
{
yield break;
}
}
else if (logName == null)
{
yield break;
}
// Check if entered log name is a duplicate for the authenticated user
List<LogInfo> checkDuplicateLog = this.GetSingleLog(logName);
if (checkDuplicateLog.Count > 0)
{
yield break;
}
PerformanceCounterCategory category = new PerformanceCounterCategory(categoryName, theMac[0].MachineName);
if (category.CategoryName == null || category.MachineName == null)
{
yield break;
}
List<LogInfo> logIt = new List<LogInfo>();
if (category.CategoryType != PerformanceCounterCategoryType.SingleInstance)
{
List<InstanceInfo> instances = modsDB.GetInstancesFromCatMacName(theMac[0].MachineName, category.CategoryName);
foreach (InstanceInfo inst in instances)
{
if (!category.InstanceExists(inst.InstanceName))
{
continue;
}
else if (inst.InstanceName.Equals(instanceName, StringComparison.OrdinalIgnoreCase))
{
PerformanceCounter perfCounter = new PerformanceCounter(categoryName, counterName,
inst.InstanceName, theMac[0].MachineName);
//CounterSample data = perfCounter.NextSample();
//double value = CounterSample.Calculate(data, perfCounter.NextSample());
string data = "";
List<UserInfo> currUser = this.GetUserByName(WindowsIdentity.GetCurrent().Name);
string timeStarted = DateTime.Now.ToString("MM/dd/yyyy - h:mm:ss tt");
List<string> dataValues = new List<string>();
for (int i = 0; i < seconds; i++)
{
data = "Value " + i + ": " + perfCounter.NextValue().ToString();
DataValueInfo datItUp = new DataValueInfo
{
Value = data
};
yield return datItUp;
dataValues.Add(data);
Thread.Sleep(1000);
}
string timeFinished = DateTime.Now.ToString("MM/dd/yyyy - h:mm:ss tt");
Log log = new Log
{
LogName = logName,
CounterName = perfCounter.CounterName,
InstanceName = perfCounter.InstanceName,
CategoryName = perfCounter.CategoryName,
MachineName = perfCounter.MachineName,
TimeStarted = timeStarted,
TimeFinished = timeFinished,
PerformanceData = string.Join(",", dataValues),
UserID = currUser[0].UserID
};
this.CreateLog(log);
break;
}
}
}
else
{
PerformanceCounter perfCounter = new PerformanceCounter(categoryName, counterName,
"", theMac[0].MachineName);
string data = "";
List<UserInfo> currUser = this.GetUserByName(WindowsIdentity.GetCurrent().Name);
string timeStarted = DateTime.Now.ToString("MM/dd/yyyy - h:mm:ss tt");
List<string> dataValues = new List<string>();
for (int i = 0; i < seconds; i++)
{
data = "Value " + i + ": " + perfCounter.NextValue().ToString();
DataValueInfo datItUp = new DataValueInfo
{
Value = data
};
yield return datItUp;
dataValues.Add(data);
Thread.Sleep(1000);
}
string timeFinished = DateTime.Now.ToString("MM/dd/yyyy - h:mm:ss tt");
Log log = new Log
{
LogName = logName,
CounterName = perfCounter.CounterName,
InstanceName = perfCounter.InstanceName,
CategoryName = perfCounter.CategoryName,
MachineName = perfCounter.MachineName,
TimeStarted = timeStarted,
TimeFinished = timeFinished,
PerformanceData = string.Join(",", dataValues),
UserID = currUser[0].UserID
};
this.CreateLog(log);
}
}
從LogController.cs：
[AcceptVerbs("GET", "POST")]
public IEnumerable<DataValueInfo> Log_Perf_Data(string machine_name, string category_name, string counter_name, string instance_name,
string log_name, long? seconds, string live, string enforceQuery)
{
LogController.CheckUser();
// POST api/log/post_data?machine_name=&category_name=&counter_name=&instance_name=&log_name=&seconds=
if (machine_name != null && category_name != null && counter_name != null && log_name != null && seconds.HasValue && enforceQuery == null)
{
List<DataValueInfo> dataVal = logDB.LogTimedPerfDataLive(machine_name, category_name, counter_name, instance_name,
log_name, seconds).ToList();
logDB.SaveChanges();
foreach (var val in dataVal)
yield return val;
}
yield break;
}
謝謝你你的時間和考慮。
使用'yield'關鍵字創建的迭代器函數旨在根據請求提取下一個項目。它們不像彗星，它將數據從服務器推送到客戶端。也許你應該對彗星技術做一點研究。 –
我不認爲解決方案很簡單，因爲客戶端代碼也會等待完整響應。 我同意@KendallFrey，如果你想這樣做，你將不得不使用彗星。 –
謝謝。我會把彗星編碼放在控制器中嗎？ – praetor