TLTCP components problem
lazarus / 38-Networking and Web Programming

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zdenal027 · 2011-04-14 14:47

Hello,

I'm trying to write program which use two TLTCP components - I need to
connect to two servers with different ports. When enable only one
TLTCP component (comment out TCP*.Connect(...) of second one), it
behaves well. But when both are enabled, program hangs after while
(about 5 seconds, so some packets are received and send). Simplified
code inserted below. BTW, in the listbox I can see "connecting...",
"connected", but "connection accepted" never appears... Is is ok?
Thanks for any help!

Best regards,
Zdenek Materna

Code: [Select]procedure TMainForm.ConnectClick(Sender: TObject);
begin
  Stream1.SetSize(0);
  StatusBar.SimpleText := 'connecting...';
  ListBox1.Items.Add('connecting...');
  TCPSock.Connect(Host.Text, Port.Value);
  TCPcom.Connect(Host.Text, Port1.Value);
end;

procedure TMainForm.TCPcomAccept(aSocket: TLSocket);
begin
   ListBox1.Items.Add('TCPcom: connection accepted on server');
end;

procedure TMainForm.TCPcomConnect(aSocket: TLSocket);
begin
   ListBox1.Items.Add('TCPcom connected');
end;

procedure TMainForm.Button1Click(Sender: TObject);
var
  mes : AnsiString;
begin

  mes := ...
  ListBox1.Items.Add('sending : ' + mes);
  TCPcom.SendMessage(mes);
end;

procedure TMainForm.TCPcomDisconnect(aSocket: TLSocket);
begin
ListBox1.Items.Add('TCPcom: disconnect');
end;

procedure TMainForm.TCPcomError(const msg: string; aSocket: TLSocket);
begin
  ListBox1.Items.Add('TCPcomError: ' + msg);
end;

procedure TMainForm.TCPcomReceive(aSocket: TLSocket);
var
buff: string;
recv: integer;
hor: integer;
vert: integer;
begin

     recv :=  aSocket.GetMessage(buff);

   ListBox1.Items.Add('received ' + IntToStr(recv) + ' bytes: ' +
buff);

  SScanf(buff,'[PH:%d PV:%d]',[@hor,@vert]);

  vertSkutPoz.Position:=vert;
  horSkutPoz.Position:=hor;

end;

procedure TMainForm.TCPSock1Accept(aSocket: TLSocket);
begin
ListBox1.Items.Add('TCPSock: connection accepted on server');
end;

procedure TMainForm.TCPSockAccept(aSocket: TLSocket);
begin
ListBox1.Items.Add('TCPSock: connection accepted on server');

end;

procedure TMainForm.TCPSockConnect(aSocket: TLSocket);
begin
  StatusBar.SimpleText := 'sending request...';
  aSocket.SendMessage('GET /?action=stream' + #10+ #10);
end;

procedure TMainForm.TCPSockDisconnect(aSocket: TLSocket);
begin
ListBox1.Items.Add('TCPSock: disconnect');

end;

procedure TMainForm.TCPSockError(const msg: string; aSocket:
TLSocket);
begin
  StatusBar.SimpleText := 'connect failed';
  ListBox1.Items.Add('TCPSock error: ' + msg);
end;


procedure TMainForm.TCPSockReceive(aSocket: TLSocket);
var
  res, i, j : Integer;
begin
  res := aSocket.Get( buffer[0], sizeof(buffer) );
  if res = 0 then exit;
  .....
 ......
 .....
end;

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Almindor · 2011-04-14 16:36

OnAccept events are server-side not client side (TLTcpComponent can be
both a client and a server, depends on if you use .Connect or
.Listen).

So you will never see the Accept event if you're connecting.

I'm not sure why it hangs for you, if you comment the other connection
out, it works.. for both? (e.g: you uncomment one and then the other
and it always works this way).

Btw. are you Czech?

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zdenal027 · 2011-04-15 07:18

Thanks for explanation.

Exactly - when I comment out one, second runs ok. For both. I don't
know if "hang" is right description - it seems that program lives -
gui isn't responding, but when I click on button which sends TCP
paket, paket is received on server... Strange.

Yes, I'm Czech :-)

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Almindor · 2011-04-15 08:20

Tak to zdar

No neviem co je presne problem, ak mozes posli mi celu aplikaciu
(zdrojaky len) ja to skusim na echo serveri, bude to len nejaka
somarina.

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zdenal027 · 2011-04-15 08:31

Zdravím

Nejde o nic tajnýho, tak jsme to hodil na leteckou poštu:
http://leteckaposta.cz/129955109

Dík moc. Taky si myslím, že to bude nějaká chujovina.

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JD · 2011-04-15 10:49

@Almindor2
Are you the same Almindor that wrote a 2D game in FreePascal a while
back?

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Almindor · 2011-04-15 19:10

@zdenal: Pozrem a uvidim  Zajtra by som na to mal mat cast

Quote from: JD on April 15, 2011, 12:49:10 pm@Almindor2
Are you the same Almindor that wrote a 2D game in FreePascal a while
back?

Yep, that's me, I lost my old "Almindor" login with my old ISP's email
I had.

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Jishaxe · 2011-04-15 21:29

Quote from: Almindor2 on April 15, 2011, 09:10:54 pm@zdenal: Pozrem a
uvidim  Zajtra by som na to mal mat cast

Quote from: JD on April 15, 2011, 12:49:10 pm@Almindor2
Are you the same Almindor that wrote a 2D game in FreePascal a while
back?

Yep, that's me, I lost my old "Almindor" login with my old ISP's email
I had.
A cooler name would have been "AlmindorTheSecond" or "UltraAlmindor"
Wait, can't you just change your forum nickname to Almindor? Mine used
to be Joshuzzz but now it's Jishaxe 'cause I changed it?

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Almindor · 2011-04-15 22:11

Quote from: Jishaxe on April 15, 2011, 11:29:42 pmA cooler name would
have been "AlmindorTheSecond" or "UltraAlmindor"
Wait, can't you just change your forum nickname to Almindor? Mine used
to be Joshuzzz but now it's Jishaxe 'cause I changed it?

Yeah you're right

I didn't realize it can be changed from the login name.

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Jishaxe · 2011-04-15 22:13

^^

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JD · 2011-04-16 09:04

Quote from: Almindor on April 15, 2011, 09:10:54 pm@zdenal: Pozrem a
uvidim  Zajtra by som na to mal mat cast

Quote from: JD on April 15, 2011, 12:49:10 pm@Almindor2
Are you the same Almindor that wrote a 2D game in FreePascal a while
back?

Yep, that's me, I lost my old "Almindor" login with my old ISP's email
I had.

I see. By the way, whatever happened to that game of yours? Are you
still developing it?

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Almindor · 2011-04-16 09:17

Quote from: JD on April 16, 2011, 11:04:38 amI see. By the way,
whatever happened to that game of yours? Are you still developing it?

It's "shelved" atm. The latest version works (multiplayer etc.) and is
generally stable, but I have other projects (like lNet) to take care
of now. Not enough time for it.

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Almindor · 2011-04-16 10:08

Quote from: zdenal027 on April 15, 2011, 10:31:56 amZdravím

Nejde o nic tajnýho, tak jsme to hodil na leteckou poštu:
http://leteckaposta.cz/129955109

Dík moc. Taky si myslím, že to bude nějaká chujovina.

V Linuxe mi to fakci OK. Ak si zapnem server na oboch portoch a dam
connect, krasne sa oba clienti pripoja, ten TCPSock posle aj nejake
info a neuschyna mi to.

Jedine co som tam nasiel bol problem s INIStorage kde si nemal
zadefinovany port1 pricom ho citas (padlo mi to pri StrToInt ale to
som poriesil).

Este to skusim vo Windle. Mozno je problem niekde inde ako v
pripojeni, napr. ten tvoj server mozno nieco posle co sa zatentuje tam
(OnReceive?) ale to si ja neviem zopakovat kedze neviem co ti posle.

Skus si zatial OnReceive dat len aby vypisal texty pre obe spojenia ak
ti to neuschne tak bude problem tam.

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zdenal027 · 2011-04-21 13:59

Ahoj,

díky za snahu. Tu chybu s INIStorage jsem si opravil, dík. Když
vypisuju jen data co přijdou, je všechno ok. Problém vznikne asi někde
při vykreslování došlého jpegu. Ještě k tomu zatuhnutí - nevytuhne to
úplně - zatuhne video, přestane se cokoliv vypisovat do listboxů, ale
dá se hýbat trackbarama a když kliknu na Send TCP paket, tak se paket
opravdu odešle. Tlačítka se tváří že nereagují, ale kliknutím na
Send... se ty data fakt odešlou. Jsem z toho volaký zmetený :-)
Kdyžtak můžu poskytnout data co tomu chodí, jestli bys to měl jak
vyzkoušet....

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eny · 2011-04-21 14:20

Quote from: zdenal027 on April 15, 2011, 09:18:23 amThanks for
explanation.

Exactly - when I comment out one, second runs ok. For both. I don't
know if "hang" is right description - it seems that program lives -
gui isn't responding, but when I click on button which sends TCP
paket, paket is received on server... Strange.
Maybe the 2 components cannot run in the same (main) thread.
It might help if you put one (or both) in a separate thread.

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zdenal027 · 2011-04-22 08:36

Tak už to funguje. Problém byl ve funkci co dělá vykreslování jpegu. Z
pokusných důvodů jsem  zakomentoval dva řádky a ejhle... :-)

Code: [Select]procedure TMainForm.DisplayFrame(stream: TStream);
begin
  try
    stream.Position:=0;
    VideoFrame.Picture.Jpeg.LoadFromStream(stream);
  except
    ListBox2.Items.Add('error while decoding frame!');
    exit;
  end;
  //VideoFrame.Repaint;
  //Application.ProcessMessages;
  ...
VideoFrame je typu TImage.

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zdenal027 · 2011-04-22 08:41

Quote from: eny on April 21, 2011, 04:20:06 pmMaybe the 2 components
cannot run in the same (main) thread.
It might help if you put one (or both) in a separate thread.

Hello,

thanks for advice, I was ready to try it, but another solution appears
:-) It was caused by function which loads jpeg from stream to TImage.
I commented two lines at the end (VideoFrame.Repaint; and
Application.ProcessMessages;) and now it works fine. Strange...