Using a lNet UDP, created in a thread in a Lazarus/FPC linux console application.

The UDP acts as a server.
It receives a question and puts in a buffer. Another thread handles the buffer, gets the answer and put it back in a buffer. There it is picked up by the UDP’s thread and sent to the client.

I try to send using

ActSent:= Send(Buffer, sizeof(buffer), Peer);

Buffer allways has the same size: 116
Peer has ip:port
Works ok, except occasionally actsent = 114 instead of 116.
This happens abt 3 on 10000 times. Not bad really, but I don’t understand.
Speed is no issue, it happens both at a rate of abt 10 packets/s as on 100 packets/s.

The connection between the clientpc and the serverpc is a 100 MBit lan, that should handle this traffic easy.

No OnErrors are triggered.

If I increase the size from 116 to 216, it reports actsent=214. Again 2 bytes missing… what could be the issue?

tia!
John

In non-visual programs (things without forms and TApplication) you use CallAction directly to integrate lNet event handling (OnXXX calls) into your main loop.

In visual apps (TApplication/TForm etc.) lNet integrates itself automatically. You just have to assign and handle the OnXXX events, and not call CallAction.

I made a client app for WINCE by cloning and modifying the sample lclient in the lnet demos. I have 2 major problems (maybe is lnet unstable in Wince?)

1.OnConnect.
procedure TLTCPTest.OnCon(aSocket: TLSocket);
begin
showmessage( ‘Connected’); // inform user of successful connect
FConConnected := True; // this ia a boolean I added
end;
I call connect() like this:
….
if FCon.Connect(Address, p) then begin // if connect went ok
Fquit := False;
p := 1;
repeat
FCon.CallAction; // wait for “OnConnect”
Inc(p);
until FConConnected or Fquit;
Result := FConConnected;//not FQuit;
end;
This ALWAYS connects, even when the the server application is not even running. What am I doing wrong?
2. OnCanSend;
This is another mistery.
I call initialize the event like this (as per the sample on this web page)
FCon.OnCansend(Fcon.iterator);
and this is the method:
procedure TLTCPTest.CanSend(aSocket: TLSocket);
var
Sent: integer =0; // number of bytes sent each try
TempBuffer: string = ”;
begin
repeat
if Length(TempBuffer) = 0 then
TempBuffer := GetNewChunk; // get next chunk if we sent all from the l
Sent := FCon.SendMessage(TempBuffer, aSocket);
showmessage(’sent= ‘+inttostr(sent));
// remember, don’t use the aSocket directly!
Delete(TempBuffer, 1, Sent); // delete all we sent from our temporary buffer!
until (Sent = 0) or (Send_Str = ”); // try to send until you can’t send anymore

And this is the
function GetNewChunk: string;
begin
Result := copy(Send_Str, 1, 16000);
Delete(Send_Str, 1, 16000);
end;

Well, the thing is, if the showmessage stays there, all works fine, BUT when I comment that out, the OnCanSend returns a Sent =0 in the middle, i.e. it successfully sends part of the Send_Str, then it exit without finishing.
What am I doing wrong here?
I would greatly appreciate any help.
Thanks

Have you got any news about these tutorials ? Sending form fields and uploading files is what I would like to use lNet for on Mac, Win and Linux; lNet is so far the most promising and light weight suite for Lazarus. Please keep up the good work

With idhhtp i Can send post/get information to web page and receive the answer in a variable . Can i do this with lnet??

The upload procedure looks at a ListBox with the names of image files and uploads each file. The files are small – usually less than 50K each. There can be several or many at an upload. People send them, and we add them to the database and upload them to the web site.

Meanwhile, as a workaround, I’ve been processing two files and uploading them to stay under the five file upload limit, since each file is uploaded as a small version and a large version, (removed the small version code from code below)

Everything seems to work, except that it stops at five files. It looks at the ListBox and reads the file names, but the upload stops. I tested to see if a file is stopping it, by using a different set of files, and same thing happens…

This code is mostly the same as the LNET FTP example. What can be incorrect?
I tried sending the code with this letter several times, but is there a limit on size of messages?