Update MIME types associated to font extensions .ttf, .woff, .woff2, and .otf

[davidstosik]

What?

This PR updates the MIME types associated to font file extensions .ttf, .woff, .woff2, and .otf to the more recent types prefixed with font/.

Why?

Working on deploying a simple Rails application to Fly.io, I noticed that even though it was serving most of my assets gzipped (content-encoding: gzip), the TTF font that it serves was desperately uncompressed (and heavy!).
It turns out that, as a precompiled asset, it gets served with the header content-type: application/octet-stream, and I believe this is due to Rack's MIME types.
I believe this content-type might be excluded from getting gzipped by Fly.io's reverse proxy (and maybe other hosting solutions too?).

Looking into it, I noticed that .woff and .woff2 were using deprecated MIME types and decided to update them too.

How?

Simply updated the values in Rack's hash that associates file extensions to MIME types.

Anything Else?

Resources on the IANA website:

• font/woff:

  File extension(s): woff
  (...)
  Deprecated Alias: The existing registration "application/font-woff" is deprecated in favor of "font/woff".

• font/woff2:

  File extension(s): woff2

• font/ttf:

  File extension(s): Font file extensions used for TrueType / OFF / OpenType fonts: .ttf and .otf

Note that it might be worth revisiting the .otf too, but I was unable to find clear information about this extension. (font/otf exists, but the .otf extension is also associated with application/vnd.oasis.opendocument.formula-template.)

rack/lib/rack/mime.rb

Line 413 in b172805

".otf" => "application/vnd.oasis.opendocument.formula-template",

For reference, I added this to my Rails application's config/initializers/assets.rb, as a temporary workaround:

Rack::Mime::MIME_TYPES[".ttf"] = "font/ttf"

[ioquatix]

Regarding otf, what does the Ruby mime-types gem say about it? I find that is a good source of truth.

[davidstosik]

@ioquatix .otf seems to be associated to the font type:

- !ruby/object:MIME::Type
  content-type: font/otf
  encoding: base64
  extensions:
  - otf
  xrefs:
    rfc:
    - rfc8081
    template:
    - font/otf
  registered: true

It also looks like application/vnd.oasis.opendocument.formula-template is associated with extensions .odf and .odft.

[simi]

To make (web)fonts support complete, what about eot? Not sure what's the adoption today, but it was popular earlier due to IE.

[ioquatix]

I would be fine for .otf -> font/otf. That seems reasonable to me.

I don't have any opinion about eot. I suppose in order to keep the list "short", we try to only include relevant, modern, mime types. So, I guess on that bases, if eot is no longer in common usage, I'd suggest we don't add it.

[ioquatix]

@davidstosik will you update the PR and add .otf?

[davidstosik]

Sure!

(By the way, .eot is in there already, mapped to application/vnd.ms-fontobject. font/eot does not seem to be a thing, so there's nothing to change for this one.)

[ioquatix]

@davidstosik Do you mind adding an entry to the changelog, thanks!

[davidstosik]

Done! Am I supposed to add my GitHub handle, or is that reserved to maintainers?

[ioquatix]

You can add it.