Updated mime type for binary buffer

[sbtron]

The registration request is still pending with IANA but getting the PR started for issue #944

In addition to switching to a specific MIME type do we also want to change the recommended extension (.bin) to something else?
My current thinking is rather than creating a new extension we can keep the recommended extension to .bin but add an implementation note that the implementations could chose to have a different extension if they wanted. This would essentially mean any glTF loader should not explicitly check for a .bin extension and simply load whatever filename the buffer uri points to.

[emackey]

Consider that most web servers serve static files using a lookup table to map file extensions to HTTP MIME type headers. One cannot reasonably expect web servers to be reconfigured to serve all *.bin files as application/gltf-buffer. Most web servers ship pre-configured to serve .bin as application/octet-stream.

For example, see the 6th entry in this table: MDN's Incomplete List of MIME Types

Apache's list: https://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types

application/octet-stream	bin dms lrf mar so dist distz pkg bpk dump elc deploy

We cannot save anything to a *.bin file on disk, put it on a web server, and expect the server to serve anything other than application/octet-stream.

[emackey]

IIS 7 does this too:

            <mimeMap fileExtension=".bin" mimeType="application/octet-stream" />

(Taken from %windir%\system32\inetsrv\config\applicationHost.config)

[donmccurdy]

Do we know if common servers like Apache or Nginx have rules for classic extensions like OBJ, DAE, or FBX?

[emackey]

Do we know if common servers like Apache or Nginx have rules for classic extensions like DAE or FBX?

They do not, and perhaps we should nudge them to add .glb and such.

But my objection here is that many servers, including at least Apache and IIS, already do have factory rules for *.bin, and it is not OK for us to override that.

[donmccurdy]

But my objection here is that many servers, including at least Apache and IIS, already do have factory rules for *.bin, and it is not OK for us to override that.

Makes sense. Just trying to gauge the likelihood of their handling .glb or a possible replacement for .bin appropriately.

[emackey]

So, to serve glTF correctly, one must manually add the corresponding MIME types to the server configuration. Moving away from bin and octet-stream just makes one more custom thing that needs registration.

Cesium registers all glTF-related files here for IIS and here for Node Express. Neither one needs to register bin to get this working, as bin is already registered.

[sbtron]

Great points. Open suggestions for an alternative extension
.buf ??

[donmccurdy]

couple more ideas in no order

• .glbin
• .glbuf

[emackey]

No particular preference on my part. I like .glbin, since it seems like we could more easily explain the rename from bin. But any of these seems fine.

[bghgary]

I don't have a strong preference either, but I prefer the extension to be easily distinguishable from .glb since GLB files can also reference external binary files. Both .glbin and .glbuf start with .glb. Is that confusing?

[donmccurdy]

I don't have a strong preference either, but I prefer the extension to be easily distinguishable from .glb

Since .glb is Binary glTF I could see .glbin causing confusion. .glbuf seems pretty distinct despite having the same first three letters IMO. Or we could consider more explicit alternatives like .gltfbuffer.

[pjcozzi]

@sbtron? 😄😄😄

[lexaknyazev]

Superseded by #1877.