Mac Address/Printer Status in Linux

[odvesims]

Hey There!!

Can anyone please show me how to get Mac Address of my network interface AND the printer status in linux? I use WMI for windows to get this information, but wmi unit is not supported by linux so I'd like a linux-supported equivalent to get such information. Thanks.

[odvesims]

I figured how to read the Mac address, now I'd only need to check the printer status.

[Bart]

I figured how to read the Mac address

Share it here.

Bart

[Jurassic Pork]

hello,
for mac address have a look here
for printer status use a runcommand with a  lpq command.

friendly, J.P

[odvesims]

I figured how to read the Mac address

Share it here.

Bart

My bad, I meant to share both solutions after I figured the 2nd one. But here it is: (I got it from 'gerson.rodriguez' answer at this thread: http://forum.lazarus.freepascal.org/index.php/topic,10465.msg160800.html#msg160800

Code: Pascal  [Select][+][-]

1. function getLinuxMacAddress() : string
2. const
3.        linux_path = 'sys/class/net/%s/address';
4.        default_device = 'eth0';
5. var
6.        f           : textfield;
7.        device   : string;
8.        path      : string;
9.        address : string;
10. begin
11.        Result:= '';
12.        device = default_device;
13.        path = Format(linux_path, [device]);
14.        if not FileExists(path) then
15.                Result:= '';
16.        end
17.        else
18.        begin
19.                AssignFile(f, path);
20.                reset(f);
21.                readln(f, address);
22.                Result:= address;
23.        end;
24. end;

[odvesims]

hello,
for mac address have a look here
for printer status use a runcommand with a  lpq command.

friendly, J.P

I tried using RunCommand('lpq', myString), but it results in an empty string. I currently do not have any installed/connected printer. Is this why it's empty?

[Leledumbo]

I tried using RunCommand('lpq', myString), but it results in an empty string. I currently do not have any installed/connected printer. Is this why it's empty?

Yes, without any printers installed, it will only output error message to stderr, which runcommand doesn't capture (internally it does, but it's not exposed to caller).

[Jurassic Pork]

hello,
to have stderr output on command, you can use a TProcess for example like this (to be improved)  :

Code: Pascal  [Select][+][-]

1.  var  hprocess: TProcess;
2.   OutputLines: TStringList;
3.   OutputError: TstringList;
4.  begin
5.  OutputLines:=TStringList.Create;
6.  OutputError:=TStringList.Create;
7.  hProcess := TProcess.Create(nil);
8.  hProcess.Executable := '/usr/bin/lpq';
9.  hprocess.Parameters.Add('-l');
10.  hProcess.Options := hProcess.Options + [poWaitOnExit, poUsePipes];
11.  hProcess.Execute;
12.  OutputLines.LoadFromStream(hprocess.Output);
13.  OutputError.Add('Error :');
14.  OutputError.LoadFromStream(hProcess.Stderr);
15.  if OutputError.Text <> '' then showMessage(OutputError.Text)
16.  else     ShowMessage(OutputLines.Text);
17.  hProcess.Free;
18.  OutputLines.Free;
19.  Outputerror.Free;
20.  end;

if you have CUPS as printing daemon and you want a printer, you can install printer-driver-cups-pdf
(printer driver for PDF writing via CUPS).

Friendly, J.P

[odvesims]

I tried using RunCommand('lpq', myString), but it results in an empty string. I currently do not have any installed/connected printer. Is this why it's empty?

Yes, without any printers installed, it will only output error message to stderr, which runcommand doesn't capture (internally it does, but it's not exposed to caller).

I was able to install my printer and I can print to it. However, issuing the "lpq" still returns an empty string. I tried with 'lpstat -p' but that status never changes. I plug/unplug my printer and it keeps saying 'Ready to print'.

[odvesims]

hello,
to have stderr output on command, you can use a TProcess for example like this (to be improved)  :

Code: Pascal  [Select][+][-]

1.  var  hprocess: TProcess;
2.   OutputLines: TStringList;
3.   OutputError: TstringList;
4.  begin
5.  OutputLines:=TStringList.Create;
6.  OutputError:=TStringList.Create;
7.  hProcess := TProcess.Create(nil);
8.  hProcess.Executable := '/usr/bin/lpq';
9.  hprocess.Parameters.Add('-l');
10.  hProcess.Options := hProcess.Options + [poWaitOnExit, poUsePipes];
11.  hProcess.Execute;
12.  OutputLines.LoadFromStream(hprocess.Output);
13.  OutputError.Add('Error :');
14.  OutputError.LoadFromStream(hProcess.Stderr);
15.  if OutputError.Text <> '' then showMessage(OutputError.Text)
16.  else     ShowMessage(OutputLines.Text);
17.  hProcess.Free;
18.  OutputLines.Free;
19.  Outputerror.Free;
20.  end;

if you have CUPS as printing daemon and you want a printer, you can install printer-driver-cups-pdf
(printer driver for PDF writing via CUPS).

Friendly, J.P

Says it cannot find executable '/usr/bin/lpq'.

[Jurassic Pork]

hello,
on my system ( Lubuntu 16.04 64 bits (Debian)  )  lpq is installed with the package cups-bsd . Have you this package or a similar package installed on your system ?

[odvesims]

hello,
on my system ( Lubuntu 16.04 64 bits (Debian)  )  lpq is installed with the package cups-bsd . Have you this package or a similar package installed on your system ?

I installed cups-bsd and now it's returning "is Ready, no entries". But this status doesn't change if I plug/unplug the printer.

[Jurassic Pork]

same thing for me with my hp usb printer. With the command lpq Printer is always ready when i unplug it. 
to detect usb printer unplugged try the commands :

Code: Pascal  [Select][+][-]

1. lpinfo -v

or

Code: Pascal  [Select][+][-]

1. sudo /usr/lib/cups/backend/usb

[odvesims]

same thing for me with my hp usb printer. With the command lpq Printer is always ready when i unplug it. 
to detect usb printer unplugged try the commands :

Code: Pascal  [Select][+][-]

1. lpinfo -v

or

Code: Pascal  [Select][+][-]

1. sudo /usr/lib/cups/backend/usb

Great! lpinfo -v did it for me. How can I speed up the command execution? It's taking +4 seconds. Is there a way I can set a background thread that will check this while the program is executing? I have no experience with multi-threading in lazarus.

[Jurassic Pork]

How can I speed up the command execution? It's taking +4 seconds. Is there a way I can set a background thread that will check this while the program is executing? I have no experience with multi-threading in lazarus.

For the multithread, have a look to the wiki here
For example you can do something like that :
1 - Create a new unit with the threaded procedure :

Code: Pascal  [Select][+][-]

1. unit mythread;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6. uses
7.   Classes, SysUtils;
8.  
9. Type
10.   TShowStatusEvent = procedure(Status: String) of Object;
11.  
12.   TMyThread = class(TThread)
13.   private
14.     fStatusText : string;
15.     FOnShowStatus: TShowStatusEvent;
16.     procedure ShowStatus;
17.     function ReadInfo() : String;
18.   protected
19.     procedure Execute; override;
20.   public
21.     Constructor Create(CreateSuspended : boolean);
22.     property OnShowStatus: TShowStatusEvent read FOnShowStatus write FOnShowStatus;
23.   end;
24.  
25.  
26.  
27. implementation
28. uses process;
29. constructor TMyThread.Create(CreateSuspended : boolean);
30. begin
31.   FreeOnTerminate := True;
32.   inherited Create(CreateSuspended);
33. end;
34.  
35. procedure TMyThread.ShowStatus;
36. // this method is executed by the mainthread and can therefore access all GUI elements.
37. begin
38.   if Assigned(FOnShowStatus) then
39.   begin
40.     FOnShowStatus(fStatusText);
41.   end;
42. end;
43.  
44. procedure TMyThread.Execute;
45. var
46.   newStatus : string;
47. begin
48.   fStatusText := 'TMyThread Starting...';
49.   Synchronize(@Showstatus);
50.   fStatusText := 'TMyThread Running...';
51.   NewStatus := ReadInfo();
52.       if NewStatus <> fStatusText then
53.         begin
54.           fStatusText := newStatus;
55.           Synchronize(@Showstatus);
56.         end;
57.  
58. end;
59. function TMyThread.ReadInfo(): String;
60.  var  hprocess: TProcess;
61.   OutputLines: TStringList;
62.   OutputError: TstringList;
63.  begin
64.  OutputLines:=TStringList.Create;
65.  OutputError:=TStringList.Create;
66.  hProcess := TProcess.Create(nil);
67.  hProcess.Executable := '/usr/sbin/lpinfo';
68.  hprocess.Parameters.Add('-v');
69.  hprocess.Parameters.Add('--timeout');
70.  hprocess.Parameters.Add('1');
71.  hProcess.Options := hProcess.Options + [poWaitOnExit, poUsePipes];
72.  hProcess.Execute;
73.  OutputLines.LoadFromStream(hprocess.Output);
74.  OutputError.Add('Error :');
75.  OutputError.LoadFromStream(hProcess.Stderr);
76.  if OutputError.Text <> '' then ReadInfo := OutputError.Text
77.  else     ReadInfo := OutputLines.Text;
78.  hProcess.Free;
79.  OutputLines.Free;
80.  Outputerror.Free;
81.  end;
82. end.
83.  

on Unix be sure that you have defined UseCThreads  (custon options : -dUseCThreads ) because you can have this in your lpr file :

Code: Pascal  [Select][+][-]

1. uses
2.   {$IFDEF UNIX}{$IFDEF UseCThreads}
3.   cthreads,
4.   {$ENDIF}{$ENDIF}  

in your form unit something like that :

Code: Pascal  [Select][+][-]

1.  
2. //uses mythread;
3.  
4. private
5.       MyThread: TMyThread;
6.       procedure ShowStatus(Status: string);
7. // ================
8. procedure TForm1.Button6Click(Sender: TObject);
9. begin
10.    MyThread := TMyThread.Create(true);
11.    MyThread.OnShowStatus := @ShowStatus;
12.    MyThread.Start;
13. end;    
14.  
15. procedure TForm1.FormDestroy(Sender: TObject);
16. begin
17.    if MyThread <> Nil then  MyThread.Terminate;
18. end;
19.  
20.  
21. procedure TForm1.ShowStatus(Status: string);
22. begin
23.    Memo1.Append(Status);
24. end;    
25.  

Friendly, J.P