[solved]null-terminated stream

einsTeIn.NET

Hi there,

afaik strings in NAV are containing their length in the first character. So, they are not null-terminated (like in C). I want to transfer some data to an external system. The connection type is socket and the data should be transfered as stream. The external system expects a null-termination at the end of a stream.
I did the following...

IF ISCLEAR(CC2) THEN 
  CREATE(CC2);
IF ISCLEAR(SBA) THEN 
  CREATE(SBA);

CC2.AddBusAdapter(SBA, 0);
OutMsg := CC2.CreateoutMessage('Sockets://localhost:5006');

OutS := OutMsg.GetStream();

OutS.WRITETEXT('Some Text 1');
OutS.WRITETEXT('Some Text 2');
OutS.WRITETEXT('Some Text 3');
OutS.WRITETEXT();

IF NOT OutMsg.Send(0) THEN
...

but the external system doesn't react. So, I wonder if the stream isn't null-terminated and the external system doesn't catch the message.

Xypher

You could try doing...

//nullchar declared as Text (length 1~) or Char, whatever you want
nullchar[1] := 0;

//...YourCode...

OutS.WRITETEXT('Some Text 1');
OutS.WRITETEXT('Some Text 2');
OutS.WRITETEXT('Some Text 3');
OutS.WRITETEXT(); 
OutS.WRITE(nullchar);

//...etc...

Let me know if it works

einsTeIn.NET

I'm not sure if I could test it like this

CU 50000 (single instance)

OnRun()
IF ISCLEAR(CC2) THEN
  CREATE(CC2);

IF ISCLEAR(SBA) THEN
  CREATE(SBA);

CC2.AddBusAdapter(SBA,0);
SBA.OpenSocket(6006,'');

CC2::MessageReceived(VAR InMessage : Automation "''.IDISPATCH")
InMsg := InMessage;

InS := InMsg.GetStream();

WHILE NOT (InS.EOS) DO BEGIN
  IF InS.READ(Txt) > 0 THEN
    FOR i := 1 TO STRLEN(Txt) DO BEGIN
      charint := Txt[i];
      MESSAGE('%1 = %2',Txt[i],charint);
    END;
END;

InMsg.CommitMessage();

CU 50001

OnRun()
IF ISCLEAR(CC2) THEN 
  CREATE(CC2);
IF ISCLEAR(SBA) THEN
  CREATE(SBA);
NullChar[1] := 0;

CC2.AddBusAdapter(SBA, 0);
OutMsg := CC2.CreateoutMessage('Sockets://localhost:6006');

OutS := OutMsg.GetStream();
OutS.WRITE('1st Text');
OutS.WRITE('2nd Text');
OutS.WRITE(NullChar);

OutMsg.Send(0);

but if... it doesn't work. I don't know how null character would be displayed in NAV, but should I get a message off it?

Xypher

I'm not sure what you're asking...

Are you referring to the MessageReceived procedure, or in general how NAV would handle a NULL terminating string when displaying?

einsTeIn.NET

2nd one. General handling. After some test I think NAV won't display anything. And I think NAV will interpret a zero byte as EOS.

OnRun()
IF ISCLEAR(CC2) THEN
  CREATE(CC2);
IF ISCLEAR(SBA) THEN
  CREATE(SBA);

Text1 := '1st Text';
Text2 := '2nd Text';
Text1[4] := 0;

CC2.AddBusAdapter(SBA, 0);
OutMsg := CC2.CreateoutMessage('Sockets://localhost:6006');

OutS := OutMsg.GetStream();
OutS.WRITE(Text1);
OutS.WRITE(Text2);

OutMsg.Send(0);

If so I can be sure of that NAV creates a stream the external system is able to understand.
If not and there are other reasons why NAV doesn't display the whole stream, I have no chance to proof if the external system receives an understandable stream. In any case not with two NAV clients.

einsTeIn.NET

With an outstream variable you will get the null-terminated string / zero byte as EOS if you use

OutS.WRITE

If you use

OutS.WRITETEXT

you won't get it.