Writing JSON - No Source File error (Django)

[rob8624]

Hi folks, first, i hope I've formatted my code correctly if not apologies. I'm using Exiftool in a Python/Django app where the user can edit data from an uploaded image, the data is stored in a JSON database field, I then want to write the edited exif data back to the image.

I'm using Python's subprocess to interact with exiftool, I can successfully extract data and it's rendered correctly to an editable form from a JSON field in my model. I can also edit this data and write it back to the database, but when I try to write it to the file, which is being excessed via Django's Path attribute, I get this error. IT doesn't crash my server but no edited data is written, obviously.

Code Select Expand

No SourceFile 'C:/Users/foo.bar.jpg' in imported JSON database
My relevant code....

#get image obj

Code Select Expand

image = Uploaded_Image.objects.get(id=image_id)#get data from request and do some custom 'cleaning'

Code Select Expand

cleaned_data = clean_data_from_request(request)#writing to dict to model field (exif_data) as valid JSON

Code Select Expand

image.exif_data = json.dumps(cleaned_data)

I am then doing this to try and write the JSON

Code Select Expand

subprocess.check_output(["exiftool", f"-json={image.exif_data}", image.image.path ])This is rendering the error i'm unsure on how to debug it and find out where the problem lies.

Any input muchly appreciated.
NB..i tried to pass exiftool to subprocess like this as per docs... but it returns a syntax error.

Code Select Expand

subprocess.check_output(["exiftool", -json=image.exif_data, image.image.path ])

[StarGeek]

The No SourceFile ... in imported JSON database occurs when the filename you are passing to exiftool doesn't match any of the SourceFile entries in the json file.

For example, this json file has a SourceFile of "y:\!temp\Test4.jpg", but I'm passing a different file to the command.

Code Select Expand

C:\>type temp.txt
[{
  "SourceFile": "y:/!temp/Test4.jpg",
  "XMP-dc:Description": "Test"
}]

C:\>exiftool -P -overwrite_original -json=temp.txt y:\!temp\Test3.jpg
No SourceFile 'y:/!temp/Test3.jpg' in imported JSON database
(full path: 'y:/!temp/test3.jpg')

[rob8624]

Ok cheers StarGeek. So the sourcefile within the JSON has to match the file it's being written too? OK. I'll have a look tomorrow when I have some more time are report back.

[StarGeek]

Take time to read the docs on the -j (-json) option.  If there is a SourceFile entry, it must match the file. In this case the json file is a lookup table for any file that is being processed.

If you don't have a SourceFile entry, then

An object with a missing SourceFile or a SourceFile of "*" defines default tags for all target files

[rob8624]

Cheers for the link, I've matched sourcefile and also removed the key and tried a Asterix as a value but I'm still getting the same error.

[StarGeek]

Make sure and test the command on the command line to make sure it works before including it in a script.

Can you share a sample json?

[rob8624]

Just thinking, the JSON is not being served via a file but from a JSON obj created via json.dumps. Does the command handle that? Doc say - "or import JSON file if JSONFILE is specified"

Here is a partial sample of what i'm trying to write.

{"SourceFile": "*", "ExifToolVersion": "12.77", "FileName": "RM_foobar.jpg", "Directory": "C:/Users/..../images", "FileSize": "2.9 MB", "FileModifyDate": "2024:02:25 09:55:14+00:00", "FileAccessDate": "2024:02:25 09:55:14+00:00", "FileCreateDate": "2024:02:25 09:55:14+00:00", "FilePermissions": "-rw-rw-rw-", "FileType": "JPEG", "FileTypeExtension": "jpg", "MIMEType": "image/jpeg", "ExifByteOrder": "Little-endian (Intel, II)", "PhotometricInterpretation": "RGB", "Make": "NIKON CORPORATION", "Model": "NIKON Z 6_2", .........}

[StarGeek]

It has to be a file or it can come from STDIN by using a hyphen -, e.g. -json=-.  It cannot directly accept json data.  Doing so should have gotten an error,
Error opening JSON file '<json data>'

[rob8624]

Yea that is exactly what I get, Error opening JSON file -- then the data. So, is it possible to write JSON in the way I intend?

[StarGeek]

It cannot directly accept json data.

[rob8624]

Yea. OK, looks like Exiftool isn't capable of doing this, this way. Thanks for the help, and back to the drawing board

[rob8624]

Ok. Got this working, partially as it's only writing some of the edited tags (it's not writing edited keywords). I just dumped the dict as JSON (as I was doing originally), wrote that to a temporary file then passed it to subprocess to run the exiftool command. All works.

Thanks for help with this, muchly appreciated, I'll work on getting it fully working but it's progress !