Feature to fetch style.json from a url

[YoelRidgway]

It would be nice to be able to define a stylesheet from a url in the configuration. I imagine it would look something like this in the config:

"styles": {
    "remote": {
      "style": "https://api.maptiler.com/maps/streets-v2/style.json?key=********************",
      "tilejson": {
        "type": "overlay"
      }
    },
}

Would this be possible? I was thinking that the style could be fetched when the app is launched (or if the config is reloaded using SIGHUP). I could probably add this feature myself, but would like to get the opinion of any contributors first in case there is a good reason not to add this.

[acalcutt]

there was some discussion about that before in https://osmus.slack.com/archives/C0436FK28C9/p1698761198318819

I think mainly this code would need to be changed to read from a http url if the file started with http
https://github.com/maptiler/tileserver-gl/blob/master/src/serve_style.js#L215-L221

[YoelRidgway]

Hey thanks for the response. I don't have access to the osmus slack, so don't know what was discussed there, but I can implement this if no one has anything against it.

That said, I suppose adding a fetch to this part of the code would require quite a bit of refactoring to make the add function async. I see that there is a TODO note mentioning this and it would be good for file reading performance so I suppose it should happen at some point!

[acalcutt]

I think a feature like this would be a good addition.

There would be a few places that might need some check if the path is a http string. I had mentioned in the slack we were using isValidHttpUrl in utils.js in some places for the pmtiles urls.