write tags to a darktable xmp file fails

[andrew-taylor]

Not sure if this a bug or a feature request - but writing tags to a darktable xmp files fails for me

$ curl -sO https://upload.wikimedia.org/wikipedia/commons/3/3f/JPEG_example_flower.jpg
$ darktable JPEG_example_flower.jpg
$ naturtag -t 10277 JPEG_example_flower.xmp
Not a valid path: /tmp/JPEG_example_flower.xmp
$ exiv2 JPEG_example_flower.jpg.xmp
File name       : JPEG_example_flower.jpg.xmp
File size       : 4426 Bytes
MIME type       : application/rdf+xml
...
$ naturtag -t 10277 JPEG_example_flower.jpg
$ 

[JWCook]

Looks like darktable is creating the file in the format {basename}.jpg.xmp instead of {basename}.xmp. I can add support for that soon.

[JWCook]

@andrew-taylor I made some updates that you can test out by installing the latest pre-release build:

pip install -U --pre naturtag

Now, if you run

naturtag -t 10277 JPEG_example_flower.jpg

It will find and update the XMP file created by darktable. Currently you can't select a .xmp file directly, only via an associated image file. That's something I could add if you'd like, though.

[andrew-taylor]

Thanks. Now breaks with a different error from libxmp for me (appended). Yes I think being able to write xmp file directly would be useful. Andrew

naturtag -t 10277 JPEG_example_flower.jpg
Traceback (most recent call last):
  File "/home/andrewt/.local/bin/naturtag", line 8, in <module>
    sys.exit(main())
  File "/usr/lib/python3/dist-packages/click/core.py", line 1128, in __call__
    return self.main(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/click/core.py", line 1053, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python3/dist-packages/click/core.py", line 1395, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/lib/python3/dist-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/click/decorators.py", line 26, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/home/andrewt/.local/lib/python3.10/site-packages/naturtag/cli.py", line 187, in tag
    metadata_list = list(tag_images(image_paths, observation, taxon))
  File "/home/andrewt/.local/lib/python3.10/site-packages/naturtag/metadata/inat_metadata.py", line 81, in tag_images
    return [_tag_image(image_path) for image_path in get_valid_image_paths(image_paths, recursive)]
  File "/home/andrewt/.local/lib/python3.10/site-packages/naturtag/metadata/inat_metadata.py", line 81, in <listcomp>
    return [_tag_image(image_path) for image_path in get_valid_image_paths(image_paths, recursive)]
  File "/home/andrewt/.local/lib/python3.10/site-packages/naturtag/metadata/inat_metadata.py", line 73, in _tag_image
    img_metadata.write(
  File "/home/andrewt/.local/lib/python3.10/site-packages/naturtag/metadata/image_metadata.py", line 134, in write
    img.modify_xmp(fixed_xmp)
  File "/home/andrewt/.local/lib/python3.10/site-packages/pyexiv2/core.py", line 101, in modify_xmp
    self.img.modify_xmp(self._dumps(data), encoding)
RuntimeError: XMP Toolkit error 102: Indexing applied to non-array
Failed to encode XMP metadata.

[JWCook]

Okay, it must have something to do with the metadata that darktable is writing. Using that example image without any changes works fine for me:

curl -sO https://upload.wikimedia.org/wikipedia/commons/3/3f/JPEG_example_flower.jpg
naturtag -t 10277 JPEG_example_flower.jpg

It should be fixable, though. I've run into this before with other image editors, and usually it's a case where there are conflicting data types shoved into the same metadata field (like writing a plain string where an array is supposed to go). Could you attach your modified image and sidecar that result in that error? If so, I should be able to narrow down which field is the problem.

Also I'm surprised the exiv2 CLI works here, since naturtag is also using exiv2 under the hood.

[JWCook]

Okay, I was able to reproduce it locally and get it fixed (or at least a temporary workaround; the root cause seems fairly obscure).

Try updating again:

pip install -U --pre naturtag

And this should now work as expected:

curl -sO https://upload.wikimedia.org/wikipedia/commons/3/3f/JPEG_example_flower.jpg
darktable JPEG_example_flower.jpg
naturtag -t 10277 JPEG_example_flower.jpg

And you can also select only the .xmp file now, if you want:

naturtag -t 10277 JPEG_example_flower.jpg.xmp

[andrew-taylor]

Apologies for slow reply I've been travelling Confirming working for me (thanks!)