Sleep mode and asynchronous socket Error

Capturing the exception would be nice. And as I think about it, you are right that I should in case all else fails. I use Asta Client Socket and Asta sever socket.

Still, I want to catch it happening at the client end so that my client doesn't call for tech support after resuming from sleep / hibernation and not being connected to the server. Plus the guy who is paying me has a legitimate e security concern as he would prefer a person logs off before walking away from a connected client.

Is there away for the client to become of aware of an impending sleep / hibernation?
Thanks!

John Ullom

Regarding the sleep mode you can try the attached code. I have never worked with Asta Server Socket, if I find anything about it I will post again, if not hopefully someone else can post.

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;
 
type
  TForm1 = class(TForm)
  private
    procedure WMPowerbroadcast(var Msg: TMessage); message WM_POWERBROADCAST;
  public
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.DFM}
 
{ TForm1 }
 
const
  PBT_APMQUERYSUSPEND       = $0;
  PBT_APMQUERYSTANDBY       = $1;
  PBT_APMQUERYSUSPENDFAILED = $2;
  PBT_APMQUERYSTANDBYFAILED = $3;
  PBT_APMSUSPEND            = $4;
  PBT_APMSTANDBY            = $5;
  PBT_APMRESUMECRITICAL     = $6;
  PBT_APMRESUMESUSPEND      = $7;
  PBT_APMRESUMESTANDBY      = $8;
  PBTF_APMRESUMEFROMFAILURE = $1;
  PBT_APMBATTERYLOW         = $9;
  PBT_APMPOWERSTATUSCHANGE  = $A;
  PBT_APMOEMEVENT           = $B;
  PBT_APMRESUMEAUTOMATIC    = $12;
 
procedure TForm1.WMPowerbroadcast(var Msg: TMessage);
begin
  case Msg.wParam of
    PBT_APMQUERYSUSPEND: // Request to suspend
      begin
        // Handle closing your connection here
      end;
    PBT_APMQUERYSUSPEND: ;// Suspend is about to happen
  end;
end;
 
end.
                                              

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I found the following while searching for "Socket Error" in C:\Asta\docs\ASTA.PDF
Unfortunately I'm unable to test it out myself.

This code shows how you could use the TAstaServerSocket.OnCheckOutSession Event.

procedure TServerDM.ServerSocketCheckOutSession(Sender: TObject; At: TAstaThread; ClientSocket: TCustomWinSocket; Session: TComponent);
begin
  with TAstaDataModule(Session) do
  ServerSocket.RecordServerActivity(ClientSocket, 'Check out for '+FPersistentCheck);
end;

The following code insures that certain socket errors are not shown in the server log.
procedure TServerDM.ServerSocketClientError(Sender: TObject; Socket: TCustomWinSocket; ErrorEvent: TErrorEvent; var ErrorCode: Integer);
begin
  //we can ignore these
  if (ErrorCode=10053) or (ErrorCode=10054) then ErrorCode:=0;
end;

1.6.1.1 ASTA Jump Start Tips
1. Always code the AstaclientSocket.OnDisconnect event even with a comment or set the
new AstaclientSocket.SQLErrorHandling.seNoExceptiononDisconnect to true. It is
imperative that your know when your client disconnects so ASTA will raise an exception
by default unless you assign the OnDisconnect event or set the
seNoExceptionOnDisconnect to true.


Also to add to the previous post where you place your code to "Handle closing your connection"

if Msg.lParam = 1 then // you can decide not to hibernate by setting Msg.Result := 1;
// if Msg.lParam <> 1, hibernate mode will be forced by for example low battery

Hope this helped.

Hi Jonas,

   Thanks for your help. I have partially implemented your code on my server side. I can catch the suspend and sleep events but can't seem to catch the Query to Suspend or Query to Sleep.
   Any idea why that would be? I'll keep working at it.

I'll also implement your suggestion on the server side.  I am still getting a handle on Asta server side coding as lazy programmers can usually ignore it.
Thanks for help

I found this article.

 http://msdn.microsoft.com/en-us/library/aa372716.aspx
I am running Vista. Apparently  PBT_APMQUERYSUSPEND   and  PBT_APMQUERYSTANDBY. My guess that they don't want you messing with these events in order to enforce consistent behavior.

So far, I have avoided having to figure out how to write code that is Windows Version Dependent. Can one even do that in Delphi? Sounds like a pain to maintain.

I'll work with the SUSPEND and STANDBY events to shut things down in a orderly fashion.

Thanks for the input on Asta question. Above and beyond and in the end a better approach to preventing server issues. Thanks again!!