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
10

Is there any update on the easiest way to do this? I am trying to get the status and label information for a tool outside of DOpus using Python but am having a hard time doing so.

Any help will be appreciated!

11

Maybe a custom command (that writes to a temp file) that would be called from python via dopusrt ?
A bit cumbersome though ....
Or a script that outputs information in a structured output file that you can feed to your python script (more steps and more manual).

12

Do you know how to get the information in the first place? I haven't been able to find anything in the dopusrt documentation that will allow access to the information. Also haven't found anything in the documentation that allows scripts or plugins to access it, either.

13

Metadata can be accessed from the item object (Item [Directory Opus Manual]) through the metadata property.
Then you can go through the metadata itself with this metadata object (Metadata [Directory Opus Manual]).

For the labels, even though I never tested this, using the Labels method of the item object might lead you to what you need.

The item object itself if easily retrievable from selection, or from scanning a folder, or from its path (first from the scriptCommandData object passed into the entry point of the command, last two from FSUtil.ReadDir and FSUtil.GetItem)

14

Thank you! That information is very helpful. I'll let you know if I end up having any other questions, but hopefully this will solve my dilemma.

1 Like
15

Another thought : Depending on what the python script is doing, you might have to consider one of the three options : 1) calling Opus (custom command in JScript ... or VB) from Python; 2) calling Python from Opus ; 3) Doing everything from Opus.

EDIT: As said before, option 1) is probably better to be done via dopusrt.exe and a file with content result. Note that dopusrt.exe calls are asynchronous: once called, you get back to the caller even if the command called takes several minutes to execute (even seconds might be a problem to address). And you don't have the ability to get any content in return from dopusrt.exe.

16

Option 1 is probably best for my purpose but I may also look into option 3. And thanks for the note about it being asynchronous! Fortunately the application I am writing is already multi-threaded, so the thread that would be talking to DOpus can wait around until the temp file is done being written to without blocking much.