TServerSocket - Limiting Connections - Thread - go-pugleaf

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9 total messages Started by Joe St. Onge Mon, 21 Jun 2004 19:41

TServerSocket - Limiting Connections

#5753

Author: Joe St. Onge
Date: Mon, 21 Jun 2004 19:41

15 lines
1577 bytes

I have a application which accepts external connections from remote units,
this application is working great.  There is a problem when more than one
unit attempts to connect to the server at the same time.  The application is
designed for servicing one remote unit at a time.

What I need to do is to limit the Server Connections to 1 at a time.  The
application set the Server Socket to port 3002, when a remote unit connects
to 3002 the servicing begins, I need to prevent the Server Socket from
accepting another connection until that remote unit completes.

Anyone know how to restrict the number of connections that a server socket
will accept?

Regards,
Joe

Re: TServerSocket - Limiting Connections

#5754

Author: Hans Galema
Date: Mon, 21 Jun 2004 20:46

8 lines
1152 bytes

Joe St. Onge wrote:

> Anyone know how to restrict the number of connections that a server socket
> will accept?

The way to to that is to Close the Socket that comes in as second.

Hans.

Re: TServerSocket - Limiting Connections

#5755

Author: Remy Lebeau (TeamB)
Date: Mon, 21 Jun 2004 22:05

11 lines
1272 bytes

"Joe St. Onge" <jstonge@nel-techlabs.com> wrote in message
news:40d739d9@newsgroups.borland.com...

> Anyone know how to restrict the number of connections
> that a server socket will accept?

Use the OnAccept event to Close() the new connection.


Gambit

Re: TServerSocket - Limiting Connections

#5758

Author: Joe St. Onge
Date: Tue, 22 Jun 2004 14:59

49 lines
2302 bytes

Hi Remy,

I did what you said and received the following error "exception class
EListError with message 'List index out of bounds (0)' "

This is the OnAccept code that I used...

void __fastcall TMainForm::ChanServerSocketAccept(TObject *Sender,
      TCustomWinSocket *Socket)
   {
   if (MainForm->Connections++)
      ChanServerSocket->Close();
   }

I then tried changing the routine to

void __fastcall TMainForm::ChanServerSocketAccept(TObject *Sender,
      TCustomWinSocket *Socket)
   {
   if (MainForm->Connections)
      MainForm->ChanServerSocket->Socket->Connections[1]->Close();
   }

and received the following error "exception class EListError with message
'Asynchronous socket error 10053' "

Isn't there a method to shutoff listening after accepting a connection and
keeping the current connection active???

Thanks,
Joe



"Remy Lebeau (TeamB)" <gambit47.no.spam@no.spam.yahoo.com> wrote in message
news:40d75c9d$1@newsgroups.borland.com...
>
> "Joe St. Onge" <jstonge@nel-techlabs.com> wrote in message
> news:40d739d9@newsgroups.borland.com...
>
> > Anyone know how to restrict the number of connections
> > that a server socket will accept?
>
> Use the OnAccept event to Close() the new connection.
>
>
> Gambit
>
>

Re: TServerSocket - Limiting Connections

#5759

Author: Hans Galema
Date: Tue, 22 Jun 2004 15:08

20 lines
1585 bytes

Joe St. Onge wrote:

> Hi Remy,

A selective greeting for one of the replyers.

> void __fastcall TMainForm::ChanServerSocketAccept(TObject *Sender,
>       TCustomWinSocket *Socket)
>    {
>    if (MainForm->Connections++)
>       ChanServerSocket->Close();

Why do you use a MainForm->Connection ? TServerSocket keeps
track of the number of active connections. And why do you
close The ChanServerSocket instead of the actual Socket;

	if ( ChanServerSocket->Socket->ActiveConnections )
		Socket->Close();

Hans.

Re: TServerSocket - Limiting Connections

#5760

Author: Joe St. Onge
Date: Tue, 22 Jun 2004 15:23

38 lines
2227 bytes

Hans,

I modified my code as you suggested...

void __fastcall TMainForm::ChanServerSocketAccept(TObject *Sender,
      TCustomWinSocket *Socket)
   {
   if (ChanServerSocket->Socket->ActiveConnections > 1)
      Socket->Close();
   }

What happened is that the Socket->Close() also closed my existing socket.  I
am attempting to keep one connection per socket and not accept any more
connections on that socket until the first has finished...


"Hans Galema" <dontusethis@dontusethis.nl> wrote in message
news:40d84b21$1@newsgroups.borland.com...
> Joe St. Onge wrote:
>
> > Hi Remy,
>
> A selective greeting for one of the replyers.
>
> > void __fastcall TMainForm::ChanServerSocketAccept(TObject *Sender,
> >       TCustomWinSocket *Socket)
> >    {
> >    if (MainForm->Connections++)
> >       ChanServerSocket->Close();
>
> Why do you use a MainForm->Connection ? TServerSocket keeps
> track of the number of active connections. And why do you
> close The ChanServerSocket instead of the actual Socket;
>
> if ( ChanServerSocket->Socket->ActiveConnections )
> Socket->Close();
>
> Hans.

Re: TServerSocket - Limiting Connections

#5762

Author: Remy Lebeau (TeamB)
Date: Tue, 22 Jun 2004 16:54

17 lines
1296 bytes

"Joe St. Onge" <jstonge@nel-techlabs.com> wrote in message
news:40d84965$1@newsgroups.borland.com...

>       ChanServerSocket->Close();

Change that to this instead:

    Socket->Close();

> Isn't there a method to shutoff listening after accepting a
> connection and keeping the current connection active???

No.


Gambit

Re: TServerSocket - Limiting Connections

#5764

Author: Remy Lebeau (TeamB)
Date: Tue, 22 Jun 2004 16:58

15 lines
1470 bytes

"Hans Galema" <dontusethis@dontusethis.nl> wrote in message
news:40d84b21$1@newsgroups.borland.com...

> if ( ChanServerSocket->Socket->ActiveConnections )

The ActiveConnections property is incremented before the OnAccept event is
triggered.  Your code would effectively disconnect *all* incoming
connections, not allowing a single connection to remain active.  You should
be doing this instead:

    if ( ChanServerSocket->Socket->ActiveConnections > 1 )


Gambit

Re: TServerSocket - Limiting Connections

#5763

Author: Remy Lebeau (TeamB)
Date: Tue, 22 Jun 2004 17:01

22 lines
1916 bytes

"Joe St. Onge" <jstonge@nel-techlabs.com> wrote in message
news:40d84edf$1@newsgroups.borland.com...

> What happened is that the Socket->Close() also closed my existing socket.

Not possible.  Every connection has its own TCustomWinSocket instance.
Disconnecting one socket does not have any effect on other existing sockets.

> I am attempting to keep one connection per socket and
> not accept any more connections on that socket until the
> first has finished...

Worse case scenerio, you may just have to resort to changing to a different
component, or even just acessing the WinSock API directly.  TServerSocket
was not designed to handle only a single connection, but instead handles
multiple connections.  It can be used for a single connection, but at the
cost of first accepting all connections and then closing any connection that
you don't want.


Gambit

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