"Martin James" <nospam@dial.pipex.com> wrote in message
news:452265ff@newsgroups.borland.com...
> J
>>
>> Ok, so I can just adjust my Athread.Connecdtion.ReadLn
>> TO: AThread.Connection.ReadLn(', 60) ???
>
> Yes.
Thanks
>> Why? - I was assuming it could be done by using a TTimer and simply going
>> through an array of AThreads and sending a 'ping' to their connection? -
>> Maybe a sloppy way of doing it but I thought it should work ;)
>
> It is overkill - you do not need a timer with Indy, or any serial number,
> or array stuff. Like Remy says, if the read times out at the client, send
> a poll to the server and set a flag to say that the poll has been sent.
> If *any data at all* is received from the server, clear the flag. If the
> read time out again with the flag set, the server is not responding.
Great idea. Good ol' Booleans always useful eh? :)
>
>>> Also, you don't need serial numbers in the pings at all, since the
>>> server
>>> would only be interested in knowing that data is still flowing through
>>> the
>>> connection in general, not necessarily what the data actually is.
>>
>> Very good point!... My thought was to use the serials to basically keep
>> track of what pings had received a reply....
>
> Use peer IP address/port?
Not sure what you mean here. Yes the connection uses IP's and ports but what
does that have to do with ping-pong keep alives? - Sorry maybe I'm just
thick ;)
>>
>> But supposing soem sort of accidental error has happened (god knows
>> what)... if you don't give the client a 2nd chance then it could be
>> wrongly disconnected.
>
> Well, if you want, you can keep a retry count at the client, or server, or
> both.
Might be the best idea actually. Still a lot of people using 56k out
there...
>
> EG 56k modem utilising full bandwidth could block a ping - Or
>> sending a file down the very same connection would make it unusable for a
>> while (until the file has finished). How would I deal with this?
>
> You do not need to - if *any data at all* is received from the other end,
> whether this is a poll, poll-reply, command, response, file-chunk,
> whatever, clear the flag. If data is being received, the reads will not
> time out and the polls will not be sent - they are not needed since data
> is obviously flowing. Polls only need to be sent when the data flow
> stops, at which point the read calls will start timing out.
Ok - Thanks for your help Martin - especially the flag idea!
