Error stop Http Listener
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Hello everyone, Here is my simple application code for a Windows Service application. The question is, when stop the service, there is always, // [System.InvalidOperationException] = {"Please call the Start() method before calling this method."} Does anyone have any ideas why there is such issue and how to fix?
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.ServiceProcess;
using System.Text;
using System.Net;
using System.Threading;namespace TestServiceStop1
{
public partial class Service1 : ServiceBase
{
private Thread _tHttpThread;
private TestHttpServer _server;public Service1() { InitializeComponent(); } protected override void OnStart(string\[\] args) { \_server = new TestHttpServer(this); \_tHttpThread = new Thread(\_server.StartListen); \_tHttpThread.Start(); } protected override void OnStop() { // stop HTTP server \_server.Stop(false); } } public class TestHttpServer { // listening HTTP port private int \_Port = 0; // internal wrapped HTTP listener private HttpListener \_Server = new HttpListener(); private Service1 \_manager; public TestHttpServer (Service1 manager) { \_manager = manager; } public int ListenPort { get { return \_Port; } set { \_Port = value; } } public void StartListen() { try { IAsyncResult result; \_Server.Prefixes.Add(String.Format("http://+:{0}/", 9099)); \_Server.Start(); while (true) { result = \_Server.BeginGetContext(new AsyncCallback(this.HttpCallback), \_Server); result.AsyncWaitHandle.WaitOne(); } } // any exceptions are not expected // catch InvalidOperationException during service stop // \[System.InvalidOperationException\] = {"Please call the Start() method before calling this method."} catch (Exception ex) { throw ex; } }George_George wrote:
while (true) { result = _Server.BeginGetContext(new AsyncCallback(this.HttpCallback), _Server); result.AsyncWaitHandle.WaitOne(); }
In your StartListen you get in this endless loop. So after stopping the server the call to
_Server.BeginGetContext(new AsyncCallback(this.HttpCallback), _Server);
most likely throws this exception. You will need to check if the _Server object is still active before calling the BeginGetContext I guess...
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George_George wrote:
while (true) { result = _Server.BeginGetContext(new AsyncCallback(this.HttpCallback), _Server); result.AsyncWaitHandle.WaitOne(); }
In your StartListen you get in this endless loop. So after stopping the server the call to
_Server.BeginGetContext(new AsyncCallback(this.HttpCallback), _Server);
most likely throws this exception. You will need to check if the _Server object is still active before calling the BeginGetContext I guess...
Thanks GDavy, How do check whether _Server is still active? Any suggestions? :-) regards, George
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George_George wrote:
_Server.Stop();
I can't find where you are stopping the thread. You are just stopping the HTTPListener, not the thread.
OnStop()method should be able to exit the thread also, I guess. Not sure this will be the reason for error.All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
Sorry N a v a n e e t h, My English is not very good. You mean I need to stop the thread tHttpThread in OnStop? regards, George
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Sorry N a v a n e e t h, My English is not very good. You mean I need to stop the thread tHttpThread in OnStop? regards, George
George_George wrote:
You mean I need to stop the thread tHttpThread in OnStop?
Yes. The thread is not stopping in your code. Stop that on
OnStop()method.All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
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George_George wrote:
You mean I need to stop the thread tHttpThread in OnStop?
Yes. The thread is not stopping in your code. Stop that on
OnStop()method.All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
Thanks N a v a n e e t h, How to stop the thread gracefully? I think of using Abort, but we have discussed before this method call is not a good idea always. regards, George
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Thanks GDavy, How do check whether _Server is still active? Any suggestions? :-) regards, George
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George_George wrote:
You mean I need to stop the thread tHttpThread in OnStop?
Yes. The thread is not stopping in your code. Stop that on
OnStop()method.All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
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Thanks N a v a n e e t h, How to stop the thread gracefully? I think of using Abort, but we have discussed before this method call is not a good idea always. regards, George
Go with this[^]. It will work.
All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
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Actually because the BeginGetContext call will throw an exception when the _Server object is stopped, the thread will stop too so no extra work is actually required.
I mean the thread which he created.
All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
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I mean the thread which he created.
All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
;) I know which thread you mean. The thread he creates uses the StartListening Function. In that function the BeginGetContext call is made, and this will throw the InvalidOperationException when the _Server object is stopped. So the thread he creates really does exit when the _Server stops. He will just need to catch the InvalidOperationException and evaluate that it is expected behaviour.
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from MSDN on the BeginGetContext call[^] The InvalidOperationException is thrown when the server is stopped. So there you go it is normal behaviour. You can check the IsListening Property to see if the _Server is started or not.
Thanks GDavy, Your solution works. Cool! regards, George
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;) I know which thread you mean. The thread he creates uses the StartListening Function. In that function the BeginGetContext call is made, and this will throw the InvalidOperationException when the _Server object is stopped. So the thread he creates really does exit when the _Server stops. He will just need to catch the InvalidOperationException and evaluate that it is expected behaviour.
Thanks GDavy! If I fixed in this way, are there any need to stop the tHttpThread thread?
while (true) { if (\_Server.IsListening) { result = \_Server.BeginGetContext(new AsyncCallback(this.HttpCallback), \_server); result.AsyncWaitHandle.WaitOne(); } else { break; } }regards, George
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;) I know which thread you mean. The thread he creates uses the StartListening Function. In that function the BeginGetContext call is made, and this will throw the InvalidOperationException when the _Server object is stopped. So the thread he creates really does exit when the _Server stops. He will just need to catch the InvalidOperationException and evaluate that it is expected behaviour.
GDavy wrote:
In that function the BeginGetContext call is made, and this will throw the InvalidOperationException when the _Server object is stopped. So the thread he creates really does exit when the _Server stops. He will just need to catch the InvalidOperationException
I know. I was suggesting him to stop that thread when
HTTPListenerstops, so it won't call againBeginGetContext(). Will that be a good method than catching exception, and thread getting aborted automatically ?All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
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Hello everyone, Here is my simple application code for a Windows Service application. The question is, when stop the service, there is always, // [System.InvalidOperationException] = {"Please call the Start() method before calling this method."} Does anyone have any ideas why there is such issue and how to fix?
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.ServiceProcess;
using System.Text;
using System.Net;
using System.Threading;namespace TestServiceStop1
{
public partial class Service1 : ServiceBase
{
private Thread _tHttpThread;
private TestHttpServer _server;public Service1() { InitializeComponent(); } protected override void OnStart(string\[\] args) { \_server = new TestHttpServer(this); \_tHttpThread = new Thread(\_server.StartListen); \_tHttpThread.Start(); } protected override void OnStop() { // stop HTTP server \_server.Stop(false); } } public class TestHttpServer { // listening HTTP port private int \_Port = 0; // internal wrapped HTTP listener private HttpListener \_Server = new HttpListener(); private Service1 \_manager; public TestHttpServer (Service1 manager) { \_manager = manager; } public int ListenPort { get { return \_Port; } set { \_Port = value; } } public void StartListen() { try { IAsyncResult result; \_Server.Prefixes.Add(String.Format("http://+:{0}/", 9099)); \_Server.Start(); while (true) { result = \_Server.BeginGetContext(new AsyncCallback(this.HttpCallback), \_Server); result.AsyncWaitHandle.WaitOne(); } } // any exceptions are not expected // catch InvalidOperationException during service stop // \[System.InvalidOperationException\] = {"Please call the Start() method before calling this method."} catch (Exception ex) { throw ex; } }George_George wrote:
catch (Exception ex) { throw ex; }
You're not doing anything with the exception and then you throw a modified exception (without the original stack trace). If you want to re-throw the original exception use
throw;
Simple.
Work @ Network integrated solutions | Flickr | A practical use of the MVC pattern
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George_George wrote:
catch (Exception ex) { throw ex; }
You're not doing anything with the exception and then you throw a modified exception (without the original stack trace). If you want to re-throw the original exception use
throw;
Simple.
Work @ Network integrated solutions | Flickr | A practical use of the MVC pattern
Thanks Zoltan, Good to learn from you. Any comments to? http://www.codeproject.com/script/Forums/View.aspx?fid=1649&msg=2580309[^] regards, George
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GDavy wrote:
In that function the BeginGetContext call is made, and this will throw the InvalidOperationException when the _Server object is stopped. So the thread he creates really does exit when the _Server stops. He will just need to catch the InvalidOperationException
I know. I was suggesting him to stop that thread when
HTTPListenerstops, so it won't call againBeginGetContext(). Will that be a good method than catching exception, and thread getting aborted automatically ?All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
Thanks N a v a n e e t h, 1. Sounds good. Could you show the code please? I want to learn from you but feel do not know how to code. :-) 2. Any comments to? http://www.codeproject.com/script/Forums/View.aspx?fid=1649&msg=2580309[^] regards, George
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Thanks N a v a n e e t h, 1. Sounds good. Could you show the code please? I want to learn from you but feel do not know how to code. :-) 2. Any comments to? http://www.codeproject.com/script/Forums/View.aspx?fid=1649&msg=2580309[^] regards, George
1 -
volatile bool continue = true;
public void StartListen()
{
try
{
IAsyncResult result;
_Server.Prefixes.Add(String.Format("http://+:{0}/", 9099));
_Server.Start();
while (continue)
{
result = _Server.BeginGetContext(new AsyncCallback(this.HttpCallback), _Server);
result.AsyncWaitHandle.WaitOne();
}
}
// any exceptions are not expected
// catch InvalidOperationException during service stop
// [System.InvalidOperationException] = {"Please call the Start() method before calling this method."}
catch (Exception ex)
{
throw ex;
}
}public void Stop(bool isTerminate) { **continue = false;** \_Server.Stop(); }2 - It looks fine.
All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
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1 -
volatile bool continue = true;
public void StartListen()
{
try
{
IAsyncResult result;
_Server.Prefixes.Add(String.Format("http://+:{0}/", 9099));
_Server.Start();
while (continue)
{
result = _Server.BeginGetContext(new AsyncCallback(this.HttpCallback), _Server);
result.AsyncWaitHandle.WaitOne();
}
}
// any exceptions are not expected
// catch InvalidOperationException during service stop
// [System.InvalidOperationException] = {"Please call the Start() method before calling this method."}
catch (Exception ex)
{
throw ex;
}
}public void Stop(bool isTerminate) { **continue = false;** \_Server.Stop(); }2 - It looks fine.
All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
Thanks N a v a n e e t h, I think your code has an issue when we are executing result = _Server.BeginGetContext(new AsyncCallback(this.HttpCallback), _Server) while at the same time, Stop is called. :-) In this situation, there is no chance to check continue status variable. Any comments? regards, George
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Thanks N a v a n e e t h, I think your code has an issue when we are executing result = _Server.BeginGetContext(new AsyncCallback(this.HttpCallback), _Server) while at the same time, Stop is called. :-) In this situation, there is no chance to check continue status variable. Any comments? regards, George
Yes you are correct. I wrote it to explain the things, and don't consider it as a final code. Try with some synchronization mechanism, or the other method which GDavy suggested, it's looking good.
All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
-
Yes you are correct. I wrote it to explain the things, and don't consider it as a final code. Try with some synchronization mechanism, or the other method which GDavy suggested, it's looking good.
All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
Thanks N a v a n e e t h, Using synchronization in service stop callback method OnStop is dangerous, right? :-) If I do not understand your points correctly, please feel free to correct me and post your code. regards, George