Using Win32::API to accessing the methods of a DLL in Perl

Question

I have in my possession a Microsoft Powershell script which examines all the files in a folded ending in .wtv (Windows Media Center recorded TV programmes), extracts some metadata (using a DLL called "Toub.MediaCenter.Dvrms.dll") and then writes it to stdout:

[void][System.Reflection.Assembly]::LoadFile("C:\Toub.MediaCenter.Dvrms.dll")

# Get all files ending in .wtv

foreach ($file in gci "*.wtv")
{
  $wtv = New-Object Toub.Mediacenter.Dvrms.Metadata.DvrmsMetadataEditor($file)
  $attrlist = $wtv.GetAttributes()

  # Extract the Title and Description from the recorded programme

  $t = $attrlist["Title"].value
  $d = $attrlist["WM/SubTitleDescription"].value

  # Print them to STDOUT

  "$t"
  "$d"
}

At the moment, I run this from a Perl script and then parse the results. It works, but is messy and I'd like to drop the powershell part and do it entirely within Perl.

However, I have absolutely no idea how to link to a DLL so that I can call GetAttributes method on a file and then extract the values of Title and WM/SubTitleDescription.

I was pointed to using Win32::API, but I have no idea what the name of the library from which I want to import the function nor do I know the C prototype of the function.

As such, my code grinds to a halt because I'm not really sure what I should be doing with Win32::API. My (very basic) stub looks like this:

use Win32::API;

foreach my $file (glob("*.wtv"))
{
  my $wtv = new Win32::API(...stuck here...);

  # Complete guesswork from here on...

  print $wtv->GetAttributes("Title") . "\n";
  print $wtv->GetAttributes("WM/SubTitleDescription") . "\n";
}

I'm guessing it's probably obvious from the Powershell above on what I should be putting into the new Win32::API line and whether or not $wtv->GetAttributes is correct - but to be honest, I don't have a clue.

Can someone please point me in the right direction?

Answer 1

It looks like the power shell script is loading a .net framework dll not a C api dll the class it uses Toub.Mediacenter.Dvrms.Metadata.DvrmsMetadataEditor is most likely defined in there. I know there is some support from active state for interoperability between pearl and .net.

I don't know if you have a significant code base of perl or if that is were your knowledge lies, but power shell is perfectly able to handle your parsing needs it may be easier to go in that direction.