REST API access for changing metadata of photos

[pianojockl]

I'd like to add metadata to my photos via a script - namely GPS coordinates. Is there a way to access the REST API for this?

(My use case: when editing photos with snapseed they lose their location data. I'd like to read the location data from the original jpegs and write it back to the edited files' metadata on ente. I already have the part where I read the coordinates from the unedited files - just sending them to ente seems impossible...)

[mnvr]

There is a REST API for this. Unfortunately API endpoints are not yet surfaced in a way that the end user can quickly use but it is definitely possible.

You can use the updateFilePublicMagicMetadata function in the web app's source as a reference (there'll be similar code in the mobile app if you're more comfortable reading dart). This function eventually calls the PUT /files/public-magic-metadata endpoint.

The updateFilePublicMagicMetadata function is used in multiple places, e.g. the updateFileCaption is using it to update the caption associated with the file:

export const updateFileCaption = (file: EnteFile, caption: string) =>
    updateFilePublicMagicMetadata(file, { caption });

In your case, you wish to modify the GPS coordinates, which get saved as the lat and lng properties of public magic metadata associated with this file. So the code you want is something like updateFilePublicMagicMetadata(file, { lat, lng }).

So you should be able to, e.g. open the dev tools in your browser, edit the caption for a file, and copy the network request that gets send when you edit the caption.

However, this is where you'll run into a roadblock. The public magic metadata is end to end encrypted! So it is not going to be just about copying the REST request and modifying the JSON directly, you'll need to also

1. First encrypt the payload using the file's encryption key
2. Make sure that the version field in the update request is exactly the same as the latest version of the public magic metadata (the server checks it as an extra check to ensure buggy clients can't overwrite previous writes)

These steps are not too hard, but I also understand that if you don't have context of the code they might seem very hard. The simplest suggestion I can think of is run a modified web client where you can maybe temporarily repurpose some existing function to do your bidding. For example, you can start your web app locally

git checkout https://github.com/ente-io/ente
cd web
yarn install
yarn dev

Change the definition of updateFilePublicMagicMetadata to ignore the updates argument and instead just always update the lat lng (WARNING: untested sketch);

export const updateFilePublicMagicMetadata = async (
    file: EnteFile,
    updates: FilePublicMagicMetadataData, // ignore this
) => 
updateFilesPublicMagicMetadata([file], {lat: latForFileID(file.id), lng: lngForFileID(file.id) });

where latForFileID etc are functions where you obtain the new coordinate (if it is only a few files you can also just hardcode them and change your code as you go through the files).

Then you can trigger this function by doing something that modifies the file's public magic metadata (e.g. changing the file name or caption or date). You can also trigger it in bulk by, e.g. selecting the photos you want to update, use the "Fix time" option on the selection actions bar and update their time (which'll eventually call your modified function).

---

We do hope to in the future provide an SDK where custom functionality can be done by the user in case the app doesn't support the exact behaviour they wish for yet. Right now however, something like the above might solve your predicament. Maybe there is an even easier way, this is the solution that just came to my mind casually.

While it's obvious, I'll restate - this is just a hacky workaround, please undertake on your own risk etc.

[pianojockl]

Thanks for the quick reply!
I know I'll end up in some special place in hell for this, but I actually took your suggestions and (being on vacation and all...) asked Claude AI to enhance the CLI tool to also be able to list files and change their metadata. (Since CLI already has the authentication and encryption in place, I figured it might work)

So, the solution it gave me actually does list the files with filename, metadata, etc. in JSON and CSV formats and I was reckless enough to try and change the Caption of a photo - successfully.

I'll read through the entirety of the enhancement to see if there's anything fishy, but I'm surprised to say, it actually seems to have gotten it right.