我有一个控制台程序，其功能是使用URLs打开HttpWebRequest并在控制台窗口中显示结果。
我运行了几天（超过一周），直到今天它在此部分出现错误System.ExecutionEngineException时才出现问题：
HttpWebResponse response = (HttpWebResponse)request.GetResponse()
错误讯息：
System.Transactions Critical: 0 : <TraceRecord xmlns="http://schemas.microsoft.com/2004/10/E2ETraceEvent/TraceRecord" Severity="Critical"><TraceIdentifier>http://msdn.microsoft.com/TraceCodes/System/ActivityTracing/2004/07/Reliability/Exception/Unhandled</TraceIdentifier><Description>Unhandled exception</Description><AppDomain>Clicker.exe</AppDomain><Exception><ExceptionType>System.ExecutionEngineException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</ExceptionType><Message>Exception of type 'System.ExecutionEngineException' was thrown.</Message><StackTrace> at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.Connection.SyncRead(HttpWebRequest request, Boolean userRetrievedStream, Boolean probeRead)
at System.Net.ConnectStream.ProcessWriteCallDone(ConnectionReturnResult returnResult)
at System.Net.HttpWebRequest.WriteCallDone(ConnectStream stream, ConnectionReturnResult returnResult)
at System.Net.ConnectStream.CallDone(ConnectionReturnResult returnResult)
at System.Net.ConnectStream.CloseInternal(Boolean internalCall, Boolean aborting)
at System.Net.ConnectStream.System.Net.ICloseEx.CloseEx(CloseExState closeState)
at System.Net.ConnectStream.CloseInternal(Boolean internalCall)
at System.Net.HttpWebRequest.EndWriteHeaders_Part2()
at System.Net.HttpWebRequest.EndWriteHeaders(Boolean async)
at System.Net.HttpWebRequest.WriteHeadersCallback(WebExceptionStatus errorStatus, ConnectStream stream, Boolean async)
at System.Net.ConnectStream.WriteHeaders(Boolean async)
at System.Net.HttpWebRequest.EndSubmitRequest()
at System.Net.HttpWebRequest.SetRequestSubmitDone(ConnectStream submitStream)
at System.Net.Connection.CompleteConnection(Boolean async, HttpWebRequest request)
at System.Net.Connection.CompleteStartConnection(Boolean async, HttpWebRequest httpWebRequest)
at System.Net.Connection.CompleteStartRequest(Boolean onSubmitThread, HttpWebRequest request, TriState needReConnect)
at System.Net.Connection.SubmitRequest(HttpWebRequest request, Boolean forcedsubmit)
at System.Net.ServicePoint.SubmitRequest(HttpWebRequest request, String connName)
at System.Net.HttpWebRequest.SubmitRequest(ServicePoint servicePoint)
at System.Net.HttpWebRequest.GetResponse()
at Clicker.ClickerModule.OpenURL(CLKProxyModel proxy, CLKURLModel url)
at Clicker.ClickerModule.&lt;PrepareProxies&gt;b__20_0(CLKProxyModel proxy)
at System.Threading.Tasks.Parallel.&lt;&gt;c__DisplayClass31_0`2.&lt;ForEachWorker&gt;b__0(Int32 i)
at System.Threading.Tasks.Parallel.&lt;&gt;c__DisplayClass17_0`1.&lt;ForWorker&gt;b__1()
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.InnerInvokeWithArg(Task childTask)
at System.Threading.Tasks.Task.&lt;&gt;c__DisplayClass176_0.&lt;ExecuteSelfReplicating&gt;b__0(Object )
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.Execute()
at System.Threading.Tasks.Task.ExecutionContextCallback(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task&amp; currentTaskSlot)
at System.Threading.Tasks.Task.ExecuteEntry(Boolean bPreventDoubleExecution)
at System.Threading.Tasks.Task.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()
</StackTrace><ExceptionString>System.ExecutionEngineException: Exception of type 'System.ExecutionEngineException' was thrown.</ExceptionString></Exception></TraceRecord>
OpenURL功能：
private bool OpenURL(CLKProxyModel proxy, CLKURLModel url) {
if (!url.Link.StartsWith("http")) {
url.Link = "http://" + url.Link;
}
Uri uri;
if(!Uri.TryCreate(url.Link, UriKind.Absolute, out uri)) {
_logger.Error("Invalid URI: The hostname could not be parsed.");
return false;
} else {
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url.Link);
WebProxy wProxy = new WebProxy(proxy.IP, proxy.Port.Value);
wProxy.BypassProxyOnLocal = false;
wProxy.UseDefaultCredentials = true;
request.Proxy = wProxy;
request.KeepAlive = false;
request.UseDefaultCredentials = true;
request.Timeout = TIMEOUT;
request.ReadWriteTimeout = READWRITETIMEOUT;
request.Method = "GET";
request.Headers.Add("Accept-Language", "en-US");
request.Accept = "text/html, application/xhtml+xml, */*";
request.UserAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36";
request.ServicePoint.ConnectionLeaseTimeout = CONNECTIONLEASETIMEOUT;
request.ServicePoint.MaxIdleTime = MAXIDLETIME;
request.ServicePoint.ConnectionLimit = numberOfProxy;
try {
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse()) {
string msg = string.Format(">>>>>>\nurl: {0}, proxy: {1}:{2}\n>> {3}\n>> {4}", url.Link, proxy.IP, proxy.Port.Value, response.StatusCode, response.Headers);
Console.WriteLine(msg);
return true;
}
} catch (WebException e) {
request.Abort();
string msg = string.Format("=======\nurl: {0}, proxy: {1}:{2}\n=== {3}\n=== {4}", url.Link, proxy.IP, proxy.Port.Value, e.Status, e.Message);
Console.WriteLine(msg);
return false;
}
}
}
OpenURL将像这样调用：
Parallel.ForEach(clkProxies, proxy => {
foreach (CLKURLModel url in clkURLs) {
OpenURL(proxy, url);
int pauseTime = rand.Next(500, 2001);
Thread.Sleep(pauseTime);
}
});
为什么突然出现此错误？