[DUG] Indy Sockets - How to Receive Asynchronously

[Kyley Harris]

Also, I guess the type of data and your message layer has a big impact on
how you design your data receiver.
in my own client/servers where I control the protocol, all my messages first
send an 8byte size packet.. So my read queue is constantly just doing  ASize
:= StrToInt( '$'+ReadString(8) ) { 8 byte hex } and this is looping.. as
soon as I get a successful size I can then read the specific size of data
into a message object and continue polling. If I need to send very large
data like binary files,, I break it down into smaller packets encapsulated
in messages using the above method.

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
>
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> --
> Kyley Harris
> Harris Software
> +64-21-671-821
>
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-- 
Kyley Harris
Harris Software
+64-21-671-821
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