Hi,

I just downloaded ASINet about about an hour ago or so. (Working on the
upgrade on internal lines for ages).

Using the sample i was able to get a small programm running. I have to query
a whois-server on Port 43.

The only problem I have is, that I do not know in advance how many bytes I
will be recienving. How do I have to modify my code to handle that ?

THANKS FOR ANY HINT

Stephan


PROCEDURE Main
   LOCAL nPort := 43
   LOCAL CServername := "whois.networksolutions.com"
   LOCAL nSocket
   LOCAL cBuffer
   LOCAL nBytes
   LOCAL nError := NIL
   LOCAL CDomain := "test.com"

   nSocket := SocketOpen( SOCK_STREAM, cServername, nPort, @nError )

   IF nError <> 0
      ? "ERROR:" + LTrim(Str(nError))
   ENDIF


   SocketSend( nSocket, CDomain+chr(13)+chr(10)  )


   nBytes  := 3000                        <-------------- DAS MEINE ICH !
   cBuffer := Space( nBytes )
   nBytes  := SocketRecv( nSocket, @cBuffer, nBytes, @nError )

   SocketClose( nSocket )

   IF nError <> 0
      cBuffer := "ERROR:" + LTrim(Str(nError)) + " BYTES RECEIVED:" +
LTrim(Str(nBytes))
      ? cBuffer
   ELSE
      ? cBuffer
   ENDIF

RETURN

Hi,

What you are describing is the principal problem of a server: a client is connecting and now the server has to
find out what the client is about to do.

Thechnically spoken, there must be a protocol on above the tcp protocol, client and server have to do any kind
of handchake and communication. As example you can think of any protocol which is sitting on tcp/ip. Think of
HTTP, FTP, SMTP, POP and so on.

To your problem:

1) You can create an own protocol, for example let the first n Bytes be the length of the message. This works
since the client knows about the message length (usually). This way the server can read the first n bytes
first and thereafter tries to read as long as everything is read.

2) Another strategy is that the client is writing a special EndOfStream sequence at the and of the message and
the server reads as long as he finds this code sequence.

3) Another one is that the message is of a defined length.

Solutions:

1) read the first n bytes and allocate a suitable buffer.

2) allocate a buffer of any size and read until endofstringmarker and concatinate the different parts of the
message.

3) a suitable buffer may be allocated in advance.

Hope this helps.

--


Andreas Herdt
Alaska Software Technology AG

-------------------------------------------------------------
Technical Support EMEA: mailto:support@de.alaska-software.com
Technical Support APRA: mailto:support@us.alaska-software.com
News Server:            news://news.alaska-software.com
Homepage:               http://www.alaska-software.com
-------------------------------------------------------------



"Stephan Koenig" <S.Koenig@LaserPlus.de> schrieb im Newsbeitrag news:3c86d2b0$1@asgcom.alaska-software.com...
> Hi,
>
> I just downloaded ASINet about about an hour ago or so. (Working on the
> upgrade on internal lines for ages).
>
> Using the sample i was able to get a small programm running. I have to query
> a whois-server on Port 43.
>
> The only problem I have is, that I do not know in advance how many bytes I
> will be recienving. How do I have to modify my code to handle that ?
>
> THANKS FOR ANY HINT
>
> Stephan
>
>
> PROCEDURE Main
>    LOCAL nPort := 43
>    LOCAL CServername := "whois.networksolutions.com"
>    LOCAL nSocket
>    LOCAL cBuffer
>    LOCAL nBytes
>    LOCAL nError := NIL
>    LOCAL CDomain := "test.com"
>
>    nSocket := SocketOpen( SOCK_STREAM, cServername, nPort, @nError )
>
>    IF nError <> 0
>       ? "ERROR:" + LTrim(Str(nError))
>    ENDIF
>
>
>    SocketSend( nSocket, CDomain+chr(13)+chr(10)  )
>
>
>    nBytes  := 3000                        <-------------- DAS MEINE ICH !
>    cBuffer := Space( nBytes )
>    nBytes  := SocketRecv( nSocket, @cBuffer, nBytes, @nError )
>
>    SocketClose( nSocket )
>
>    IF nError <> 0
>       cBuffer := "ERROR:" + LTrim(Str(nError)) + " BYTES RECEIVED:" +
> LTrim(Str(nBytes))
>       ? cBuffer
>    ELSE
>       ? cBuffer
>    ENDIF
>
> RETURN
>
>

Thanks Andreas.

Well, WHOIS is a defined standard and I asume that I will not get
Networksolutions (oder Denic) to change their protokol fr me 


Does a to large buffer slow down the transmission or even cause to wait for
a timeout ?

Thanks

Stephan

"Stephan Koenig" <S.Koenig@LaserPlus.de> schrieb im Newsbeitrag news:3c875206@asgcom.alaska-software.com...
> Thanks Andreas.
>
> Well, WHOIS is a defined standard and I asume that I will not get
> Networksolutions (oder Denic) to change their protokol fr me 
>
>
> Does a to large buffer slow down the transmission or even cause to wait for
> a timeout ?
>
> Thanks
>
> Stephan

My fault, I have not recognized that you are working with clients which you can't control.

As far as I can see, following will solve the problem:

Try to read as long as there is incoming data.

cRecv   := ""
cBuffer := Space( 4096 )
do while 0 != ( nBytes := SocketRecv( .....cBuffer..... ) )
  cRecv += Substr( cBuffer, 1, nBytes )
enddo

Don't worry on speed here. 4 kB is quite a good cache size. Xbase++ does not have any performance problems on
allocating such a small amount of memory, and the socket layer will not loose speed working with larger
buffers then incoming data. On operating system level the whole string is just allocated memory with a pointer
on it. The data is copied and the pointer is moved as long there is incoming data. when there is no more data,
this stops.

Hope this helps.


--


Andreas Herdt
Alaska Software Technology AG

-------------------------------------------------------------
Technical Support EMEA: mailto:support@de.alaska-software.com
Technical Support APRA: mailto:support@us.alaska-software.com
News Server:            news://news.alaska-software.com
Homepage:               http://www.alaska-software.com
-------------------------------------------------------------

Great, thanks.

Thats what I wanted to hear.