TOPIC:

// C# code see here:
// mikehadlow.blogspot.it/2006/07/playing-with-httpsys.html
//
// to make it run without admin rights you need something like this one:
// netsh http add urlacl url="http://*:8080/" user=[username] listen=yes

#using System
#using System.Net
#using System.Text
#using System.IO
#using XsHttpListener

begin namespace XsHttpListener

function Start() as void
local oProgram as MainProgram

oProgram := MainProgram{}
oProgram:Start()

return

class MainProgram
protect _oListener as HttpListener

constructor()

_oListener := HttpListener{}

return

method Start() as void

_oListener:Prefixes:Add( "http://*:8080/" )
_oListener:Start()
Console.WriteLine( "Listening on port 8080, hit enter to stop" )
// Vulcan.NET needs this syntax
//_oListener:BeginGetContext( AsyncCallback{ self, @GetContextCallback() }, null )
_oListener:BeginGetContext( AsyncCallback{ self:GetContextCallback }, null )
Console.ReadLine()
_oListener:Stop()

return

method GetContextCallback( oResult as IAsyncResult ) as void
local oContext as HttpListenerContext
local oRequest as HttpListenerRequest
local oResponse as HttpListenerResponse
local oSB as StringBuilder
local oString as string
local oBuffer as byte[]
local oOutput as Stream

oContext := _oListener:EndGetContext( oResult )
oRequest := oContext:Request
oResponse := oContext:Response

oSB := StringBuilder{}
oSB:Append( e"\n" )
oSB:AppendFormat( e"HttpMethod: {0}\n", oRequest:HttpMethod )
oSB:AppendFormat( e"URI: {0}\n", oRequest:Url:AbsoluteUri )
oSB:AppendFormat( e"Local path: {0}\n", oRequest:Url:LocalPath )
oSB:Append( e"\n" )
foreach cKey as string in oRequest:QueryString:Keys
oSB:AppendFormat( e"Query: {0} = {1}\n", cKey, oRequest:QueryString[cKey] )
next
oSB:Append( e"\n" )

oString := oSB:ToString()
oBuffer := System.Text.Encoding.UTF8:GetBytes( oString )
oResponse:ContentLength64 := oBuffer:Length
oOutput := oResponse:OutputStream
oOutput:Write( oBuffer, 0, oBuffer:Length )

_oListener:BeginGetContext( AsyncCallback{ self, @GetContextCallback() }, null )

return

end class

end namespace

Hi Wolfgang

I tried this Listerner now and it works great. I have some questions about the style you wrote the code.

You are using the class StringBuilder, why not -> cString := "HttpMethod: "+oRequest:HttpMethod+"\n" ?
And you are using oString as string why not cString as string ?

Horst

Hi Horst,

using the StringBuilder class to concat strings is more efficient that "adding" them - at least I was told so.

Sometimes the use of the StringBuilder class makes the code more readable.

But do what you prefer...

Wolfgang

Hello Wolfgang!
I also use a HTTPListener like that and it worked ok.
But recently I tried to change the targeted .NET version from 3.5 to 4.0 and now have problems:
No problems at all in the code or in my program, no try/catch fires, but the sender gets an error "HTTP Status 400 bad request" which doesn't happen with the old version. My own test sender works like before, so I can't test it myself.
Do you happen t know if there has been a change in .NET between versions 3.5 and 4.0?
BR Kurt

Hi Kurt,

unfortunately I don't know about that as I have never used .NET 3.5 - I have started to work with 4.0 and also my sample is for .NET 4.
Do you have used netsh like this here:
// to make it run without admin rights you need something like this one:
// netsh http add urlacl url="http://*:8080/" user=[username] listen=yes

Wolfgang

Hallo Wolfgang
The Listerner runs, but when i leave the server its stops working. How i have to start this Listerner?

Horst

Hi Horst,
you have to build and install it as service. Or you can run it as task (Aufgabe).

You can find a sample how to build a Windows service here: riedmann.it/download/VulcanService.viaef

Wolfgang

Hi Wolfgang
Ohh i found it in Aufgaben. I think i have Alzheimer , i am sure i asked you one year ago.
Thanks for your passion.
Horst

Hallo Wolfgang
To let it run as a task doesnt work. After about 1houre the listener stops. Now i took a look into your service example.
But i dont know how to put this 2 prg's together
Any hint ?

Horst

Hi Horst,
please look at the configuration of your task: maybe you have configured it to stop after an hour.
I have running a listener as service in a customers site, but cannot give you that code - have to build a sample.
But unfortunately I'm much under pressure these days and have not the time to spend a hour or two to build this sample.
You need somtehing like this in your ServiceMain class:
Wolfgang

Hallo Wolfgang
Remember, i let run your listener as a task and every houre it stops, now i tryed to let it run with your service example as windows service. But also the service it stops sometimes. i have 2 Internet Server. On the newer one (MS Server 2019) its working without stop on the old one (MS Server 2008 R2) it stops. Now after 2h, i found a error message from the .Net Runtime

Anwendung: xsharpservice.exe
Frameworkversion: v4.0.30319
Beschreibung: Der Prozess wurde aufgrund einer unbehandelten Ausnahme beendet.
Ausnahmeinformationen: System.Net.HttpListenerException
bei System.Net.HttpResponseStream.Write(Byte[], Int32, Int32)
bei XsHttpListener.MainProgram.GetContextCallback(System.IAsyncResult)
bei System.Net.LazyAsyncResult.Complete(IntPtr)
bei System.Net.LazyAsyncResult.ProtectedInvokeCallback(System.Object, IntPtr)
bei System.Net.ListenerAsyncResult.IOCompleted(System.Net.ListenerAsyncResult, UInt32, UInt32)
bei System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)

and then: source Applikation Error

Name der fehlerhaften Anwendung: xsharpservice.exe, Version: 0.0.0.0, Zeitstempel: 0x5e4d0f0f
Name des fehlerhaften Moduls: KERNELBASE.dll, Version: 6.1.7601.24545, Zeitstempel: 0x5e0eb6bd
Ausnahmecode: 0xe0434352
Fehleroffset: 0x000000000000b87d
ID des fehlerhaften Prozesses: 0x6d0
Startzeit der fehlerhaften Anwendung: 0x01d5e79ad53deb84
Pfad der fehlerhaften Anwendung: d:\web\horst.korak\unvalid.ch\xsharpservice.exe
Pfad des fehlerhaften Moduls: C:\Windows\system32\KERNELBASE.dll
Berichtskennung: 1b374672-53ba-11ea-ab6e-00155dcefc02


Can u help me ? I have no idea whats that.
Horst

Hi
And i try to translate this c# into x# but wtf is listener.prefixes ? its used like a array but its not.
i tryed
FOREACH prefix AS STRING IN _oListener:Prefixes
oSB:AppendFormat( e"Prefixes: {0} = {1}\n", prefix) //, _oListener:Prefixes [prefix] )
NEXT

But the Service crashed. Btw it comes the same errormessage from .Net Runtime like the services is doing that sometimes without this part of code.

public static void DisplayPrefixesAndState(HttpListener listener)
{
// List the prefixes to which the server listens.
HttpListenerPrefixCollection prefixes = listener.Prefixes;
foreach(string prefix in prefixes)
{
Console.WriteLine(prefix);
}

Hello Horst,

you tried to access _oListener:Prefixes like a dictionary. But it seems to be just like a list of strings.
This should be the correct way (see {1} has no corresponding parameter in your version):
Stefan

Hi Stefan
Thanks that works
My fault , i did not analys what this AppendFormat is realy doing.

Thanks

Hi Horst,
sorry for not having answered, but I was really busy as a new project is in production now.
It is a production planning software, written entirely in X# and accessing data on DBFs, Oracle and PostgreSQL databases.
But I have seen that others have helped you in the meantime - and this is the bonus of a public forum.
Wolfgang

Hello Wolfgang,
I have a HttpListener in place and working, had nearly never problems in Win7 for wears. Recently I had to move to Win10, same program.
Now sometimes the sender (from outside, but in company network) gets a timeout, because my listener program just stops working after a request. I don't get any error messages in my try catch blocks neither in the functions nor in the main program.
Do you have any tip what to do to get an error message or any other hint what is going on?
BR Kurt

Hi Kurt,
unfortunately I have no idea. My only production of the httpListener is running on a Windows Server 2012 R2 (it is the server version of Windows 7, now both out of maintenance).

Wolfgang

Hallo Kurt
i used the listerner from Woffgang and every some hours it stops. Because it was only handling Get and Post, comes a HEAD request the listerner crashed. Maybe it helps.
Horst

Hello Horst,
thanks for the suggestion, but I know that I only get POST requests and I know the sender.
I am testing now, if a request is finished synchronally instead of asynchronally because in that case my program would stop. Some years ago I created it, so not all details are present in my brain. Now on new computer, new OS and SSD disk it maybe fast enough…
BR Kurt