Opens the CAP file.

Syntax:

function OpenFile(FileName: String) : DWORD;

Parameters:

FileName

[in] A path to a file.

Return values:

Description:

Use OpenFile to open an existing CAP file. If the function succeeds, you can begin to dump network traffic to this CAP file using HNFileAdapter.Get_NextPacket function.

When HNFileAdapter object works in AutoMode using of HNFileAdapter.Get_NextPacket function is impossible.

If HNFileAdapter.Queue property was set before the network adapter opening, and HNFileAdapter object Automode was set (see HNFileAdapter.AutoMode), then the traffic will be processed in the HNFileAdapter internal thread context together with HNQueue component.

Also you may gather traffic statistics and filter CAP file content if you're using BPF filter (see. HNFileAdapter.UserFilter, HNFileAdapter.Get_RecvCount, HNFileAdapter.Get_AcceptCount, HNFileAdapter.Get_RejectCount, HNFileAdapter.Get_ProcessCount).

On executing HNFileAdapter.OpenFile function HNFileAdapter component attempts to close the CAP file which was opened earlier. So, one instance of HNFileAdapter object can open only one CAP file.

If you need to open/create several CAP files simultaneously, you may create several HNFileAdapter objects with appropriate settings.

To create a new CAP file please use HNFileAdapter.CreateFile function.

Example of using HNFileAdpater object AutoMode for reading packets from the first CAP file and dumping packets to the second CAP file:

// OnFileClose event handler
procedure TForm1.HNFileAdapter1FileClose(Sender: TObject; ThParam: Pointer; Result: DWORD)
begin
    if (Result == HNERR_FILE_SIZE_LIMIT)
    begin
      ...
    end;
end;
...
// Create the first HNFileAdapter object
HNFileAdapter1 = HNFileAdapter.Create(); 
// Create the second HNFileAdapter object
HNFileAdapter2 = HNFileAdapter.Create(); 
// Create HNQueue object
HNQueue1 = HNQueue.Create(); 
...
// Set HNQueue object to HNFileAdapter objects
HNFileAdapter1.Queue := HNQueue1.Handle;
HNFileAdapter2.Queue := HNQueue1.Handle;

// HNFileAdapter additional settings
HNFileAdapter1.AutoMode := TRUE;
HNFileAdapter2.AutoMode := TRUE;

HNFileAdapter1.SizeLimit := 1000000;
HNFileAdapter1.OnFileClose := TForm1.HNFileAdapter1FileClose;

// Create CAP file
Res = HNFileAdapter1.CreateFile("packets2.cap");
...
// Start internal queue thread
Res = HNQueue1.Start();
...
// Open CAP file
Res = HNFileAdapter2.OpenFile("packets1.cap");
...