Nodejs - trying to edit images' metadata with Exiftool - json

Question

I am currently working on a NodeJS (Express) project to edit images' metadata with Exiftool.
To edit images' metadata with Exiftool, I've to create a JSON file containing all metadata to modify then execute the command :
exiftool -j=metadata.json pathToTheImage/image.jpg
The json file must look like that :
[{"SourceFile":"pathToTheImage/image.jpg","XMP-dc:Title":"Image's title"}]
Here's my code to do that :
const {exec} = require('child_process');
let fs = require('fs');
let uploadPath = "uploads";
let uploadName = "image.jpg";
...
app.post('/metadata/editor', (req, res) => {
let jsonToImport = [...];
fs.writeFileSync("metadata.json", JSON.stringify(jsonToImport));
exec('exiftool -j=metadata.json ' + uploadPath + '/' + uploadName, (error, stdout, stderr) => {
if (error) {
console.error(error);
return;
}
res.redirect('/metadata/checker/' + uploadName);
});
});
The problem is at the level of "writeFileSync/exec".
Independently these two lines work well, that's to say that if I've just the first line, the JSON file is well created. And if I've just the second ligne, image's metadata are well updated.
But when I execute this two lines together, the JSON file is well created but the exec line do "nothing" (or something that I can't determine).
This code uses synchronous functions, I've test it with asynchronous functions, this is the same behavior.
Currently, to do what I need, I must execute the code above to create the JSON file, then I must comment the writeFileSync line and I must reexecute the code to update image's metadata correctly.
It's really strange, I've try to read the JSON file content before the exec line but everything is ok. I've use asynchronous functions, with and without promise... there is nothing to do it doesn't work.
Thank you for your help.

Answer 1

I'll answer my own question:
The problem was that I use nodemon, however by default nodemon watches JSON files. But in my code I created a JSON file to use it right after. So, I created the JSON file correctly, nodemon sees it, and restarts the node server; the rest of the code does not run.
To fix this, I added an option to ignore the created files in my package.json:
"nodemonConfig": {
"ignore": [
"path/to/files/to/ingore/*"
]
}