URLs not ending with file extension can't be loaded by appendSceneAsync()

[hybridherbst]

When URLs don't end in a file extension, Babylon doesn't seem to be able to understand the served mime type or headers to determine the correct loader.

Example URL: https://cloud-staging.needle.tools/-/assets/Z23hmXB1tXjQr/1tXjQr/file

Repro

• Bug repro on playground: https://playground.babylonjs.com/#WGZLGJ#10762
• Expected result: File loads
• Current result: File does not load, exception in the console:

babylon.js?t=1731053735677:1 Uncaught (in promise) RuntimeError: 
Unable to load from https://cloud-staging.needle.tools/-/assets/Z23hmXB1tXjQr/1tXjQr/file: 
importScene of undefined from undefined version: undefined, exporter version: undefined
importScene has failed JSON parse
    at t [as constructor] (babylon.js?t=1731053735677:1:530981)
    at new t (error.ts:76:9)
    at d (sceneLoader.ts:1026:42)
    at Object.load (babylonFileLoader.ts:1056:17)
    at sceneLoader.ts:1063:35
    at f (sceneLoader.ts:643:13)
    at fileTools.ts:526:13
    at XMLHttpRequest.e (fileTools.ts:675:33)

Screenshots

Desktop (please complete the following information):

• OS: MacOS 15.1
• Browser: Chrome, Safari

Additional context

The URLs are served with the correct mime type. Other viewers load the file correctly, e.g.

• ✅ Needle Viewer: https://viewer.needle.tools/?file=https://cloud-staging.needle.tools/-/assets/Z23hmXB1tXjQr/1tXjQr/file
• ✅ three.js: https://stackblitz.com/edit/three-dev-6gar8k?file=main.js
• ✅ model-viewer: https://stackblitz.com/edit/progressive-gltf-modelviewer-aw5kts?file=index.html
• ✅ PlayCanvas: https://playcanv.as/p/cs43ZE3p/
• ❌ Babylon 😢 https://playground.babylonjs.com/#WGZLGJ#10762

[deltakosh]

As stated in our issue template please start with the forum

[deltakosh]

And here is your fix: https://playground.babylonjs.com/#WGZLGJ#10767

We ask to chat on the forum first so we augment our knowledge base there

[hybridherbst]

Thanks for the note, I opened issues here in the past just fine so must have overread the new note about the forum.

I still believe this is a bug – it should not be necessary to provide the plugin because the file is served with the correct mime-type. Other viewers support that just fine, see above.

Do you want me to open a new forum post about this nonetheless before you reopen the issue?

[deltakosh]

Well we are all different ;)
You can do two things:

• Open a feature request on the forum (in the feature request category) so people can vote and it helps us prioritize
• Do the PR and I will gladly merge it

[deltakosh]

@hybridherbst #15798 :D

(there was a 3rd option where I actually do the change ;))

[hybridherbst]

Haha, thanks so much!