[Lazarus] TInetSocket usage - any documentation available?

[Mark Morgan Lloyd]

Michael Schnell wrote:
> On 10/21/2015 12:33 AM, Bo Berglund wrote:
>> As Mark Morgan Lloyd has pointed out I *really* need to create an 
>> encapsulated class for the TCPIP communications so I can use this as 
>> an alternate component in the existing object and for this I need to 
>> implement an onReceive event to plug the incoming data into it
> 
> Sorry to be a PITA, again, but a command line application (which in the 
> other message you said you would want to do) does not support throwing 
> events from threads out of the box. (There is no Lazarus Linux workalike 
> for a Delphi Service Application.). You would have to implement your own 
> "main loop" to make this happen.
> 
> That is why, to use the standard Lazarus and Delphi programming 
> paradigms, I suggested to do a normal Lazarus GUI application on the RasPi.

Which is fine as a testbed, but not necessarily for production use. It's 
particularly not fine if you want to start it on a regular basis from 
cron or whatever, which I think Bo has already settled on.

I'm very much in two minds on this. I'm intermittently working on a 
couple of fairly large programs which have elements of both daemon and 
UI, having them as standard Lazarus apps makes inspection and debugging 
much easier but inserts a large amount of complexity- X11, the widget 
set (GTK or Qt), all of the LCL stuff- all of which has the potential 
for bugs and unintended interactions.

Even if Bo did decide not to use cron but instead to have a Lazarus app 
with its own embedded timing, he'd still have to organise startup and 
having a screen- real or simulated- to run it on. And since a Raspberry 
Pi needs a keyboard etc. in order to have a local screen, and since he's 
not sorted out automatic VNC startup etc., I don't think this is the way 
for him to go.

So noting your concern with events, the real question is still which 
libraries etc. he should be running to implement a socket client 
reliably in a console program. Or alternatively, how best to implement a 
Windows-style service using Lazarus, which doesn't mandate a screen and 
an initial login.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]