ChrisChuah

Hi

Each time i send a packet of data to the broadcast address, the same packet will be received back again.

How can i

1. control the idUDPClient to ignore the packet

2. How to determine the ip address is a broadcast address in the network

please advise

regards

chris

Thanks Remy.

Hi

When i use the IdUDPClient inside the thread object, the idUDPClient does not get any messages back even though it can be seen from the Wireshark that the message was sent back.

However, if i place the IdUDPClient on a Form, i am able to get the message.

Something funny is that when i use the IdUDPClient on the Form to send out the message, 

the first response message header is SOREQ <== this header is request header

Checking on the Wireshark, the server returned SORE

I tried to initialise the l_buf to $0 before retrieving from idUDPClient.

However, its only the first message sent that will be always SOREQ and the rest will be SORE

And the IP address returned in the message should be 192.168.84.128 which indicate the server address itself.

seems like the first message is the same message that i sent out.

please advise

regards

chris

===== Code for IdUDPClient on Form =====

procedure TForm1.Button2Click(Sender: TObject);
var
  l_port : UInt32;
  l_memStream : TMemoryStream;
  l_len : integer;
  l_buf, l_buf1 : TIdBytes;
  l_ilUDPData : Tt_BootReqMsg;
  l_ip : string;
  l_ipBytes : array[0..15] of byte;
  FMsg : string;
  FRepliedClientIP : string;
  FRepliedClientPort : Uint32;
  l_index : integer;
begin
  l_ip := getOwnIP;
  if l_ip = '' then begin
    writeLog('Cannot find own IP address');
    exit;
  end;
  IdUDPClient1.Host := '192.168.84.255';
  IdUDPClient1.Port := 55510;
  IdUDPClient1.BoundPort  := 55510;
  try
//    FUDP.Active := true;
    l_memStream := TMemoryStream.create;

    l_buf := ToBytes('SOREQ'#0, IndyTextEncoding_ASCII);
    l_memStream.Write(l_buf[0], 6);

    l_port := 55510;
    l_port := GStack.HostToNetwork(l_port);
    l_memStream.write(l_port, 4);

    getArrayBytes(l_ip, l_ipBytes);
    l_memStream.Write(l_ipBytes, SizeOf(l_ipBytes));

    l_len := l_memStream.size;
    setLength(l_buf, l_len);
    l_memStream.position := 0;
    l_memStream.Read(l_buf[0], l_len );
    l_memStream.Clear;
    try
      IdUDPClient1.ReceiveTimeout := 3000;
      IdUDPClient1.BroadcastEnabled := true;
      IdUDPClient1.SendBuffer(l_buf);
      FMsg := 'Send To Address: ' + IdUDPClient1.Host + ' Port: ' + Inttostr(IdUDPClient1.Port) + ' using IP: ' + l_ip;
      WriteLog(FMsg);
      setLength(l_buf, sizeOf(l_ilUDPData));
      for l_index := 0 to length(l_buf) - 1 do. <== initialise the buffer but i still receive SOREQ only on 1st time.
        l_buf[l_index] := byte($0);
      l_len := IdUDPClient1.ReceiveBuffer(l_buf, 2000);
      if l_len <= 0 then begin
        FMsg:='No Data received in UDP';
        FRepliedClientIP := '';
        FRepliedClientPort := 0;
        WriteLog(FMsg);
      end
      else begin
        l_memStream.Clear;
        l_memStream.Position := 0;
        l_memStream.Write(l_buf[0], l_len);
        l_memStream.Position := 0;
        setlength(l_buf1, 6);
        l_memStream.Read(l_buf1[0], length(l_buf1));
        WriteLog('Op Code: ' + getStringFromBytes(l_buf1));
        l_memStream.Read(FRepliedClientPort, sizeof(FRepliedClientPort));
        WriteLog('Port value: ' + Inttostr(FRepliedClientPort));
        l_memStream.Read(l_ilUDPData.hid, sizeof(l_ilUDPData.hid));
        FRepliedClientIP := getStringFromBytes(l_ilUDPData.hid);
        FRepliedClientPort := GStack.NetworkToHost(FRepliedClientPort);
        WriteLog('Replied. IP: ' + FRepliedClientIP + ' Port: ' + Inttostr(FRepliedClientPort));
      end;
    except
      on E:Exception do begin
        FMsg := 'Error in Recv Data in UDP: ' + e.message;
        FRepliedClientIP := '';
        FRepliedClientPort := 0;
        WriteLog(FMsg);
      end;
    end;
    l_memStream.Free;
  except
    on E:exception do begin
      FMsg := 'Exception in SoFind: ' + e.Message;
      FRepliedClientIP := '';
      FRepliedClientPort := 0;
      WriteLog(FMsg);
    end;
  end;

end;
 

==== End =====

Hi Remy

Would like to ask why the UDPClient did not receive any data.

Attached is the screen capture of the Wireshark.

The first pic shows the server received the message sent from the delphi client

The second pic shows the server sends out the SORE (response) message to the delphi client IP address.

However, the client reported that there is no data received

<27/5/2022 11:14:02 am> Send To Address: 192.168.84.255 Port: 55510 using IP: 192.168.84.129
<27/5/2022 11:14:05 am> IP:  Port: 0 replied
<27/5/2022 11:14:05 am> No Data received in UDP

Did i do something not right?

please advise

regards

chris

Thanks Remy

The only problem that i have with strings in delphi is that I dont know if they are Windows widechar or UTF8 char or ansi value

Edit1.text := 'MET';

ShowMe(Edit1.text);

Function showMe(aValue : string);

var

  l_value : string;

begin

  l_value := aValue + 'A';

  UDPClient.Write(l_value);

end;

So when the edit1 value is pass into ShowMe function, what is the length of l_value? 

As my server only accepts ANSI type of characters, the data sent may be Windows WideChar.

Hence to be on the safe side, i would have to translate it to idBytes.

What is the general rule on how you would send data when the server only accepts ANSI characters.

Please advise

regards

chris

BTW, After 20 years of using Delphi, i still remembered you were helping me last time when i was using Delphi 5, 6 in one of the forum.

Now, its hard to find help for delphi.

Hi

I am trying to create a thread that will send out UDP message and when it receive the UDP message from the server, it will send a Reply as event back to the caller.

I create the UDPClient in the Execute function and of course i would need to free it when the thread ends.

But why do i get access violation when i free it?

The call stack is

--IdSocketHandle.CloseSocket.

--IdSocketHandle.Destroy

-- System.TObject.free;

--IdUDPBase.CloseBinding

--IdUDPBase.Destroy

--IdUDPClient.Destroy

 -- System.TObject.Free

--FUDP.Free;

please help to guide me what is the best way to send out UDP message and wait for reply?

Should i use UDPServer rather than UDPClient?

=== Code ===

procedure ilUDPClientThd.Execute;
var
  l_port : UInt32;
  l_memStream : TMemoryStream;
  l_len : integer;
  l_buf : TIdBytes;
  l_ilUDPData : Tt_BootReqMsg;
  l_ip : string;
  l_ipBytes : array[0..15] of byte;
  FUDP: TIdUDPClient;
begin
  { Place thread code here }
  l_ip := getOwnIP;
  if l_ip = '' then begin
    DoOnLog('Cannot find own IP address');
    exit;
  end;
  FUDP := TIdUDPClient.Create(nil);
  FUDP.Host := FBroadcastIP;
  FUDP.Port := FBroadcastPort;
//  FUDP.Binding.Port := FBroadcastPort;
  try
    l_port := FBroadcastPort;
    l_memStream := TMemoryStream.create;

    l_buf := ToBytes('SOREQ', IndyTextEncoding_ASCII);
    l_memStream.Write(l_buf[0], 6);

    l_port := GStack.HostToNetwork(l_port);
    l_memStream.write(l_port, 4);

    getArrayBytes(l_ip, l_ipBytes);
    l_memStream.Write(l_ipBytes, SizeOf(l_ipBytes));

    l_len := l_memStream.size;
    setLength(l_buf, l_len);
    l_memStream.position := 0;
    l_memStream.Read(l_buf[0], l_len );
    l_memStream.Clear;
    try
      FUDP.ReceiveTimeout := 3000;
      FUDP.BroadcastEnabled := true;
//      FUDP.Active := true;
      FUDP.SendBuffer(l_buf);
//      FUDP.SendBuffer(l_buf[0], l_len);
      FMsg := 'Send To Address: ' + FUDP.Host + ' Port: ' + Inttostr(FUDP.Port) + ' using IP: ' + l_ip;
      Synchronize(WriteToLog);
//      l_len := FUDP.ReceiveBuffer(l_ilUDPData, sizeof(l_ilUDPData), FUDP.ReceiveTimeout);
      setLength(l_buf, sizeof(l_ilUDPData));
      l_len := FUDP.ReceiveBuffer(l_buf);
      if l_len <= 0 then begin
        FMsg:='No Data received in UDP';
        FRepliedClientIP := '';
        FRepliedClientPort := 0;
        Synchronize(ReplyToClient);
        Synchronize(WriteToLog);
      end
      else begin
        l_ilUDPData.Port := GStack.NetworkToHost(l_ilUDPData.Port);
        FRepliedClientIP := getStringFromBytes(l_ilUDPData.hid);
        FRepliedClientPort := l_ilUDPData.port;
        Synchronize(ReplyToClient);
      end;
    except
      on E:Exception do begin
        FMsg := 'Error in Recv Data in UDP: ' + e.message;
        FRepliedClientIP := '';
        FRepliedClientPort := 0;
        Synchronize(ReplyToClient);
        Synchronize(WriteToLog);
      end;
    end;
    l_memStream.Free;
    FUDP.Binding.Destroy;
  except
    on E:exception do begin
      FMsg := 'Exception in SoFind: ' + e.Message;
      FRepliedClientIP := '';
      FRepliedClientPort := 0;
      Synchronize(ReplyToClient);
      Synchronize(WriteToLog);
    end;
  end;
  FUDP.Disconnect;
  FUDP.Free; <<==== Access violation when i tried to free UDP Client 
end;

thank you very much for your advices.

Guess i think i will try to use COM dll and see if C sharp can use it or not.

18 minutes ago, Fr0sT.Brutal said:

look above

Hi

So sorry it seems like its calling DLL rather than using Delphi to create DLL isnt it?

Its been a long time since i create a DLL but isnt there an export function or something like that?

regards

chris

20 hours ago, PeterBelow said:

Create a COM dll, Delphi has a wizard for that. Google for "C# com interop" to find examples for how to use such a thing from the .NET side.

Hi

Actually I want to use delphi to create a DLL with functions or procedures containing a callback.

How can i create such functions in delphi so that the project can be compiled to a dll for C Sharp programmer to use

Previously all DLL functions does not have function pointer or callback functions when i was using Delphi 6 era.

Also my C sharp programmers said they cannot use COM because their program will be running in Docker for linux

please advise

regards

chris

Hi

I have an existing component that communicates with a server via TCP.

However, this component can only be used in delphi.

When i call a function in this component, it will send out a TCP message.

After some time, it will return back data and it will trigger an event back in the component.

So, anytime i want to use this component, i can drop the component into the form.

I can double click on the event and write codes to handle the result from the event.

Now, if i want to make this component into a DLL for C sharp programmer to use

How can i create events into the dll for C Sharp programmer to use?

Is there any example that i can use or follow

please help

regards

chris

Actually, its not easy to find components written for Delphi

For example, component to read ePassport whereby it need to capture the image of the MRZ portion of the passport and then read the NFC chip from the passport.

These are quite specialised components which you can find libraries for swift, java, c sharp etc. 

However, cant find for delphi.

Thanks but seems like that are not a lot of components for NFC for delphi.

Sometimes i wonder should i continue to develop in Delphi or move on to other programming languages.

sigh..

Hi,

is there such components for delphi to develop iOS and Android application to read the MRZ (Machine Readable Zone) and the NFC chip on passport based on MRTD (Machine Readable Travel Document) on passport?

regards

chris

thank you very much.

I will try out the indy 9 first as currently i am still using 9.0.18

somehow the idHTTP.Head is causing my thread to hang and my app also hang as well

not sure why

any ideas?

regards

chris

Hi

Currently i need to go back to maintain my source code written 10 years ago.

when i tried to run IdHTTP.Head function, sometimes it would hang there and this caused my thread to hang there.

What can i solve this "hanging" problem?

Where can i download the latest Indy 9 (9.0.50) or Can i download Indy 10 to work with Delphi 6?

please help

regards

chris

Hi

So sorry for the late reply

actually, its the problem with Adobe Acrobat with Internet Explorer.

I have to uninstall and re-install Adobe Acrobat again.

seems like that solve my problem.

regards

chris

hi

Previously it was chrome as a default but i set to Edge Browser.

However, i could not find anything about download on file type in Edge Browser.

something related to mime type?

regards

chris

Hi

In Delphi 10.4.1, when the Win64 program called WebBrowser1.Navigate("file://z:\filename.pdf") where z drive is a shared drive, it will display the pdf in the Browser.

However, when i upgraded to 10.4.2, the same function will prompt for File Download.

I also tested to navigate a C drive pdf document and it will also prompt the file download

Please help

====== source =========

procedure TForm1.Button1Click(Sender: TObject);
var
 l_filename : string;
begin
  if OpenDialog1.Execute then begin
    l_filename := OpenDialog1.FileName;
//    l_filename := 'file://' + l_filename;
    WebBrowser1.Navigate(l_filename);
  end;
end;

======= End ================

regards

chris

Hi

Has anyone done this soap interface before?

I am able to get the SOAP interface using this

https://ove-osb.microsdc.us:9015/OPERA9OSB/opera/OWS_WS_51/Information?WSDL

The WSDL Import will generate a Information.pas file.

I tried to call the LovQueryRequest but it only contains the basic XML without the headers.

Anyone knows what i should do in order to add the OGHeaders and SecurityHeaders to it?

regards

chris

i did that but it still having the same error.

if not, i wont be so frustrated over it.

sigh

Also when i start the PAServer for the first time, it did not prompt me for the password.. i wonder why

I just made a video you Youtube on this error.

hopefully the members can advise me on what the error is.

hi

when the new patch is released, the PAServer pkg is also shown on my Windows VM. So i dragged the PAServer pkg into my Mac OS to install it.

After installation, i ran my app but it showed disconnected session. On the PAServer in my MacOS, it showed 

>list

Process Control Server started pid 1647 exe built Feb 27 2020

Error: file permissions do not allow debugging.

Just today, i saw another patch is released but my PA Server still does not allow iOS debugging.

I am running Mojave instead of Catalina because Catalina does not allow the PAServer to run because it is in 32 bit.

anyone can advise?

regards

chris

Thank you very much. i will try this out.

regards

chris

btw, do you know why is there a file permission error on the PA server? 

i checked on all the user:group in the PAServer and its root:wheel.

any ideas?

Hi

Is there a function when there is switch event, to disallow the component from switching from off to on?

In my function, when the user activate the OnSwitch event, i will prompt the user to turn off?

if the user said no, then the switch should remain at On. However, now the switch will auto turn off even though i set the IsCheck to true

any ideas?

regards

chris

Is it easier to debug on the hardware?

sometimes the debugger is quite slow when returning to the breakpoint.

thats what i feel.