How to receive data multiple times in a single routine ?

[FrankBKK]

Hi,

I have a problem when I want to download more than one time in a single routine - how do I know when the transfer is completed and I can send another command to receive a different set of data ?
see below rough example - that does not work

OnMouseClick: 
   if DataPortTCP.Active then DataPortTCP.Close();
   DataPortTCP.RemoteHost:= edApcUpsDServer.Caption;
   DataPortTCP.RemotePort:= IntToStr(seApcUpsDPort.Value);
   DataPortTCP.Active := True ;
   DataPortTCP.Open();

   DataPortTCP.RemoteHost:= edApcUpsDServer.Caption;
   DataPortTCP.RemotePort:= IntToStr(seApcUpsDPort.Value);
   DataPortTCP.Active := True ;
   DataPortTCP.Open();

   // do something with the received data from command A and command B 
end ;

OnDataPortOpen: 
   if rbStatus.Checked then
       DataPortTCP.Push(#00+#06+'status');  // send msg.length + msg: 'events' ;
   else if rbEvents.Checked then
      DataPortTCP.Push(#00+#06+'events');  // send msg.length + msg: 'events' ;
end ; 

OnDataPortDataAppear: 
   gsRawData := gsRawData + DataPortTCP.Pull() ;

   // When receive a #00#00 the transmission is completed
   if Pos(#00#00, gsRawData) > 0 then  DataPortTCP.Close();
end ;

OnDataPortClose: 
   DataPortTCP.Active := False ;
   if rbStatus.Checked then
       gsRawStatus := gsRawData ; 
   else if rbEvents.Checked then
       gsRawEvents := gsRawData ; 
end ; 

[serbod]

Use TTimer component. Start timer after connection, and read/send data inside OnTimer event

…

On Thu, May 27, 2021, 14:06 FrankBKK ***@***.***> wrote: Hi, I have a problem when I want to download more than one time in a single routine - how do I know when the transfer is completed and I can send another command to receive a different set of data ? see below rough example - that does not work OnMouseClick: if DataPortTCP.Active then DataPortTCP.Close(); DataPortTCP.RemoteHost:= edApcUpsDServer.Caption; DataPortTCP.RemotePort:= IntToStr(seApcUpsDPort.Value); DataPortTCP.Active := True ; DataPortTCP.Open(); DataPortTCP.RemoteHost:= edApcUpsDServer.Caption; DataPortTCP.RemotePort:= IntToStr(seApcUpsDPort.Value); DataPortTCP.Active := True ; DataPortTCP.Open(); // do something with the received data from command A and command B end ; OnDataPortOpen: if rbStatus.Checked then DataPortTCP.Push(#00+#6+'status'); // send msg.length + msg: 'events' ; else if rbEvents.Checked then DataPortTCP.Push(#00+#6+'events'); // send msg.length + msg: 'events' ; end ; OnDataPortDataAppear: gsRawData := gsRawData + DataPortTCP.Pull() ; // When receive a #00#00 the transmission is completed if Pos(#00#00, gsRawData) > 0 then DataPortTCP.Close(); end ; OnDataPortClose: DataPortTCP.Active := False ; if rbStatus.Checked then gsRawStatus := gsRawData ; else if rbEvents.Checked then gsRawEvents := gsRawData ; end ; — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#7>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACXM37NNR4IMOSGMTMU42ITTPYRU5ANCNFSM45UAYVXQ> .

[FrankBKK]

Use TTimer component. Start timer after connection, and read/send data inside OnTimer event

Hmm, I am not sure if I understand correct:

You mean start Timer in DataPortOpen Event ? Is there a minimum/maximum time ?

[serbod]

Timer will call OnTimer event with some interval (1000 milliseconds for default). On every timer tick you can check for received data or send next data request.

…

On Fri, May 28, 2021, 04:37 FrankBKK ***@***.***> wrote: Use TTimer component. Start timer after connection, and read/send data inside OnTimer event Hmm, I am not sure if I understand correct: You mean start Timer in DataPortOpen Event ? Is there a minimum/maximum time ? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#7 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACXM37PI5QZO3DBCM3RFNUTTP3XUXANCNFSM45UAYVXQ> .

[FrankBKK]

Thank you so much for your help, I tried as suggested but I don't get any data back when I run the timer, only timeout.

Please let me know what I do wrong here:

procedure TfUpsMonitorMain.btTestTimerConnectClick(Sender: TObject);
begin
  if DataPortTi.Active then DataPortTi.Close();
  DataPortTi.Active := True ;
  DataPortTi.Open(ip,port);
end;

procedure TfUpsMonitorMain.DataPortTiOpen(Sender: TObject);
begin
  DataPortTi.Push(#00+#06+'status');  // send msg.length + msg: 'status'
  TestTimer.Enabled := True ;
end;

procedure TfUpsMonitorMain.DataPortTiDataAppear(Sender: TObject);
begin
  gsRawData := gsRawData + DataPortTCP.Pull() ;
end;

procedure TfUpsMonitorMain.tPollTimerTimer(Sender: TObject);
begin
  if sm.Pos(#00#00, gsRawData) > 0 then //End of Msg
  begin
    // check if it is a status or a events msg
    if sm.Pos('END APC', gsRawData) > 0 then
    begin
      // do something with the data here, then request another msg 
      gsRawData := '' ; // clear the received data
      DataPortTi.Push(#00+#06+'events');  // send msg.length + msg: 'events'
    end
    else
    begin
      // do something with the data here, then request another msg 
      gsRawData := '' ; // clear the received data
      DataPortTi.Push(#00+#06+'status');  // send msg.length + msg: 'status'
    end ;
  end ;
end;

[serbod]

Looks like code is correct, maybe timer interval too long, and remote device drop down connection by timeout? Try to set 10 ms interval.

…

On Sat, May 29, 2021, 19:39 FrankBKK ***@***.***> wrote: Thank you so much for your help, I tried as suggested but I don't get any data back when I run the timer, only timeout. Please let me know what I do wrong here: procedure TfUpsMonitorMain.btTestTimerConnectClick(Sender: TObject); begin if DataPortTi.Active then DataPortTi.Close(); DataPortTi.Active := True ; DataPortTi.Open(ip,port); end; procedure TfUpsMonitorMain.DataPortTiOpen(Sender: TObject); begin DataPortTi.Push(#00+#6+'status'); // send msg.length + msg: 'status' TestTimer.Enabled := True ; end; procedure TfUpsMonitorMain.DataPortTiDataAppear(Sender: TObject); begin gsRawData := gsRawData + DataPortTCP.Pull() ; end; procedure TfUpsMonitorMain.tPollTimerTimer(Sender: TObject); begin if sm.Pos(#00#00, gsRawData) > 0 then //End of Msg begin // check if it is a status or a events msg if sm.Pos('END APC', gsRawData) > 0 then begin // do something with the data here, then request another msg gsRawData := '' ; // clear the received data DataPortTi.Push(#00+#6+'events'); // send msg.length + msg: 'events' end else begin // do something with the data here, then request another msg gsRawData := '' ; // clear the received data DataPortTi.Push(#00+#6+'status'); // send msg.length + msg: 'status' end ; end ; end; — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#7 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACXM37OOCRHBBTPX7IZQMFTTQEKCXANCNFSM45UAYVXQ> .

[FrankBKK]

My bad - it was a simple typo in the original code - you are correct - it works fine now !

Many thanks for your continued help.

btw - as I am not familiar with the TCP protocol details -
what is the better approach - performance wise - to keep the connection open and poll data all the time or just connect when needed / requested ?