[DUG] Indy Sockets - How to Receive Asynchronously

Thu Dec 4 09:43:43 NZDT 2008

Eric, by using the thread, it essentially becomes your timer event.

To Oversimplify how I use blocking sockets on a client/server where the
server wants to send me information at any time..

Create a Thread
Thread has a sendmessage buffer queue,
Thread has a receivemessage buffer queue.

(This scenario is more useful when sending packets of data with
predetermined size... not so great for streaming info)

The thread code essentially tests and maintains the server connection and
does the following type thing.. use TEvent or some signal to communicate
with the main app.. Indy maintains small databuffers, but you really want to
be taking the data off the TCP stack into your own buffers as fast as you
can, otherwise the server cant keep sending when the buffer is full.

while not terminated do
begin
  if TCP.connected then
  begin
   with Connection.IOHandler do
  begin

      CheckForDataOnSource(0);// ReadFromStack(false,1,false);
      CheckForDisconnect(True);

      if not InputBufferISEmpty then
        // grab the data and put it in the receive queue

      if sendqueue not empty then sendthedata..

      sleep

  end;

end;

On Thu, Dec 4, 2008 at 9:31 AM, Eric A <eaa603 at hotmail.com> wrote:

>  Kyley,
>
> No program design yet.  Questions:
>
> 1) Inside the thread - do I have to implement a timer event to periodically
> check the buffer (since there's no "data received" event)?
>
> 2) What properties do I read to determine if there's received data
> available?
>
> 3) Do I need to use another Indy component in conjunction with the
> TCPClient for the buffering etc?
>
>
> Paul,
>
> I'll take a look at that site.  Are you using ICS extensively?
>
>
> Thanks,
> Eric
>
>
>
>
>
>
> ------------------------------
>
> Date: Thu, 4 Dec 2008 09:21:03 +1300
> From: kyleyharris at gmail.com
> To: delphi at delphi.org.nz
> Subject: Re: [DUG] Indy Sockets - How to Receive Asynchronously
>
>
> Indy is blocking, so typically on the client side, you would create a
> waiting thread that you sit the TCPClient inside and loop a readtimeout
> until the resultbuffer has some data. At that point produce a local event so
> that your main thread can grab the TCPClient and read the information.
>
> without knowing your actual program design and how your TCP layer interacts
> with your main application its hard to offer any detailed advise, sorry.
>
> On Thu, Dec 4, 2008 at 9:14 AM, Paul <paul.blommaerts at telenet.be> wrote:
>
>  Indy works blocking only
> Use ICS instead, they work blocking or non blocking.
> check www.overbyte.be
>
> Paul
>
>   ----- Original Message -----
> *From:* Eric A <eaa603 at hotmail.com>
> *To:* Delphi UsersGroup <delphi at delphi.org.nz>
> *Sent:* Wednesday, December 03, 2008 8:55 PM
> *Subject:* [DUG] Indy Sockets - How to Receive Asynchronously
>
> I have a situation where I need to communicate with a communications server
> using Indy TCP sockets.
>
> After sending the command the server returns an "OK" response with a second
> or two to acknowledge the acceptance of the command, however the reponse
> from the end device (returned via the server) may take several minutes to
> eventuate (or a else the sever returns a timeout message).  I need to be
> able to buffer the responses, be aware of when new strings arrinve, and
> carry on with other tasks.  This threading aspect shouldn't be an issue as I
> understand that Indy is naturally multitrheaded by design.
>
> I'm not familiar with using the Indy sockets and since there's no "received
> data event" (due to the nature of the design) I'm wondering how I capture
> the asynchronous responses sensibly?
>
> Does anyone have some code to show me how to use the Indy 10 TCPClient
> component in this way (for the receive part) ?  Its probably pretty simple
> but I need to get my head around it quickly.
>
> Thanks
>
> Eric
>
> ------------------------------
> Start searching now Rental properties galore.<http://a.ninemsn.com.au/b.aspx?URL=http://www.allrealestate.co.nz/cgi-bin/rsearch?a%3Dbhp%26t%3Dren%26cu?rsf%3Dmsnz_textlink&_t=26000&_r=REANZ_tagline&_m=EXT>
>
> ------------------------------
>
> _______________________________________________
> NZ Borland Developers Group - Delphi mailing list
> Post: delphi at delphi.org.nz
> Admin: http://delphi.org.nz/mailman/listinfo/delphi
> Unsubscribe: send an email to delphi-request at delphi.org.nz with Subject:
> unsubscribe
>
>
> _______________________________________________
> NZ Borland Developers Group - Delphi mailing list
> Post: delphi at delphi.org.nz
> Admin: http://delphi.org.nz/mailman/listinfo/delphi
> Unsubscribe: send an email to delphi-request at delphi.org.nz with Subject:
> unsubscribe
>
>
>
>
> --
> Kyley Harris
> Harris Software
> +64-21-671-821
>
> ------------------------------
> MSN NZ Travel Get inspired - dream, research, plan and book your next
> holiday online with
> <http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Ftravel%2Emsn%2Eco%2Enz&_t=771497011&_r=MSN_NZ_travel_hmtagline&_m=EXT>
>
> _______________________________________________
> NZ Borland Developers Group - Delphi mailing list
> Post: delphi at delphi.org.nz
> Admin: http://delphi.org.nz/mailman/listinfo/delphi
> Unsubscribe: send an email to delphi-request at delphi.org.nz with Subject:
> unsubscribe
>

-- 
Kyley Harris
Harris Software
+64-21-671-821
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://listserver.123.net.nz/pipermail/delphi/attachments/20081204/b1b78713/attachment.html 