Reading OpusMetaInformation powershell

Help & Support
1

In Powershell you can read an ADS using the get-content command with the -stream flag.

Get-Item -Path 'D:\temp\a.txt' -stream * 

   FileName: D:\temp\a.txt

Stream                   Length
------                   ------
:$DATA                   612035
OpusMetaInformation         20

But if i try to read the stream it errors.

Get-Content -Path 'D:\temp\a.txt'  -stream OpusMetaInformation
Get-Content : Could not open alternate data stream 'OpusMetaInformation' of file 'D:\temp\a.txt'.
At line:1 char:1
+ Get-Content -Path $file -stream OpusMetaInformation
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (D:\temp\a.txt:String) [Get-Content], FileNotFoundException
    + FullyQualifiedErrorId : GetContentReaderFileNotFoundError,Microsoft.PowerShell.Commands.GetContentCommand

What would be the best way to access the steams (read write and edit) out side of dopus?

2

What do you want to do with them? The format they're in isn't that easy to edit by hand.

3

I have zips of photo sets. Holidays, bday parties and such. Some have ratings and some have tags.

I want to:

  • Read the zip and look for a tag.
  • Depending on the value preform an action that will result in replacing the zip with a new one.
  • Copy tags from old zip to new zip.
  • Add Tag to indicate processed.

I want to produce a script that would process all files, hence considering PowerShell.
I could make a Dopus script. I am also considering hacking the comic book script, as there is some cross over (and it might add some value to that script for others).

4

Doing it from an Opus script would be much easier, since that gives you access to the data. You could have the Opus script run a PowerShell script/command and tell if the tags etc. if you want to do most of it in PS.

5

Could I use the DOpusRT to do it from outside of Dopus?

6

Not to read the labels

7

Ok. thanks mate.

8

If you're really determined, the [NTFS file-stream] format looks as follows:
Windows Terminal

Given a rating of "5 stars" and a tags of "touched"

afm .%H(fs-read('.default.md:\x07OpusMetaInformation'),,16)
1400000000000000
6300000000000000
0900000074006F00
7500630068006500
640000000000

The rating is at offset 16 => "63"

63~00000000000000~

The tags => "touched" is a UNICODE string whose UInt32 (DWORD) length starts at offset 32

09000000~7400~6F00~7500~6300~6800~6500~6400~0000~0000
length 9-chars, 0x74, 0x75, 0x63, 0x68, 0x65, 0x64, 0, 0

E.g.,

afm .(`$:%H('touched\x00\x00') length: $:sizeof('touched\x00\x00')`)
746F75636865640000 length: 9

You can see [xattr] file streams on an NTFS-File by typing dir /R at a console [wt.exe or cmd.exe] command-line.

1 Like
9

From some testing, via nirsoft's "AltenateStreamView" and "HxD", the structure actually appears to be:

Header:

  • 00:
    14 00 00 00 00 00 00 00
    : Probably an offset to the start of the Optional Text section, possibly to allow further expansion of the header, so probably not a good idea to ignore it!
  • 08:
    63 00 00 00
    : Rating: 0x01 = 1 star, 0x19 (25) = 2 star, 0x32 (50) = 3 star, 0x48 (75) = 4 star, 0x63 (99) = 5 star
  • 0C: cc cc cc cc
    : if zero, no comment, otherwise number of comment chars, including NUL
  • 10: tt tt tt tt
    : if zero, no tags, otherwise total chars length, including NUL, and end of tags NUL

Optional Text:

  • 14: 16-bit LE Unicode chars
    : any comment chars, then any tag chars