RE: Client connection gets forcibly closed by Server

Tech-Archive recommends: Fix windows errors by optimizing your registry

What OS and Service Pack are you using on both sides of the connection?
Also, what NIC Card Brand/Model are you using on both ends?
-------------------------------------
Chris Alton, Microsoft Corp.
SQL Server Developer Support Engineer
This posting is provided "AS IS" with no warranties, and confers no rights.
--------------------
From: "Robin" <diilbert.atlantis@xxxxxxxxx>
Newsgroups: microsoft.public.dotnet.languages.csharp
Subject: Client connection gets forcibly closed by Server
Date: Sat, 13 Oct 2007 15:39:23 -0300

Here is the run down. It is a Client/Server application where the client
requests data from the server and the request is fufilled as a reply
using
the same connection.

The "An existing connection was forcibly closed by the remote host"
exception rises on the Client under strange circumstances, since if I
track
the server's output it shows that the data was send to the Client
successfully (all 217 bytes for example), but on the Client side it gets
this exception and 0 bytes are read.

Here is how the Server is started and Reads the Socket if this helps:

protected void InitializeServer(int nPort)
{
tcpLsn = new TcpListener(nPort);
tcpLsn.Start();
tcpThd = new Thread(new ThreadStart(WaitingForClient));
tcpThd.Start();
}

public void WaitingForClient()
{
ClientData CData;
while(true)
{ /* Accept will block until someone connects */
CData.structSocket = tcpLsn.AcceptSocket();
Interlocked.Increment(ref connectId);
CData.structThread = new Thread(new ThreadStart(ReadSocket));

lock(this)
{ // it is used to keep connected Sockets and active thread
dataHolder.Add(connectId, CData);
}
CData.structThread.Start();
}
}

public void ReadSocket()
{
/* realId will be not changed for each thread, but connectId is
* changed. it can't be used to delete object from Hashtable*/
long realId = connectId;
Byte[] receive;
ClientData cd = (ClientData)dataHolder[realId];
Socket s = cd.structSocket;
int ret = 0;
string sData = null;
string[] sReceived;
bool bExit = false; // Exit on Success

while (!bExit)
{
if(s.Connected)
{
receive = new Byte[100] ;

try
{
ret = s.Receive(receive,receive.Length,0);

// Do stuff with received data AND send back a response

int sentBytes =

s.Send(Encoding.UTF8.GetBytes(sData),Encoding.UTF8.GetBytes(sData).Length,So
cketFlags.None);

}
catch (Exception e)
{

if( !s.Connected )
{
break;
}
else
cwp.mobile.utils.DisplayError(e);

}
bExit = true;
}
}
CloseTheThread(realId);
}

private void CloseTheThread(long realId)
{
try
{
ClientData clientData = (ClientData)dataHolder[realId];
clientData.structThread.Abort();
}

catch(Exception )
{ lock(this)
{
dataHolder.Remove(realId);
}
}
}

And here is how the client essentially works, it is a simple Single
Threaded
connection. And just a foot note about the code below I use it in 2
different projects, one is a wired client running on a Win32 machine and
the
other is running on a Wireless handheld running Windows Mobile, and both
are
getting the exact same problem. At first I thought it was communication
(wireless network problems) but I have my doubts.

// Pass the function data as a string and TRUE boolean value to wait for
the
reply (blocking)
private string SendServerData(string sData, bool bReadWait)
{
try
{

tcpclnt = new TcpClient();
tcpclnt.Connect(new
IPEndPoint(IPAddress.Parse(this.config.sIpAddress),
this.config.nPort));
stm = tcpclnt.GetStream();
const int byteCount = 300;
int readBytes = 0;

writeToServer(sData);

if(bReadWait)
{
bool exit = false;

while(!exit)
{
try
{ readBuffer = new Byte[byteCount];
readBytes = stm.Read(readBuffer,0,byteCount);

if(Encoding.ASCII.GetString(readBuffer,0,readBytes).Length > 0)
exit = true;
}

catch (Exception){break;}
}

stm.Close();
tcpclnt.Close();

return Encoding.ASCII.GetString(readBuffer,0,readBytes);
}
else
return "";
}
catch(SocketException sockexcep)
{
cwp.mobile.utils.DisplayError(sockexcep);

return "-1";
}
catch(Exception e)
{
cwp.mobile.utils.DisplayError(e);

return "-1";
}
}

private void writeToServer(string sData)
{

ASCIIEncoding encord = new ASCIIEncoding();
writeBuffer = encord.GetBytes(sData);

if(stm != null)
stm.Write(writeBuffer,0,writeBuffer.Length);
}

Any thoughts at all on how to improve either of these would be awesome
because I spend 2 hours googling this and have come up with nothing
substantial.

Thanks



.

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