Re: [media-types] Media subtypes containing "+"

["Martin J. Dürst" <[e-mail]>]

On 09/07/2020 05:44, Manu Sporny wrote:
> On 7/8/20 4:17 PM, Nathan Rixham wrote:
>> A very small point, which I realise is probably years too late, but in
>> usage "application/json+ld" is far more practical to use, for example in
>> a media selector, similarly "application/json+ld+did" follows the same
>> principal, subtyping reverse requires a great deal of both explantation
>> and code to handle, and gets ever more complex. Finding all
>> "application/json*" is much easier.
> 
> Very true, which is why the first MIME Type attempted for JSON-LD was in
> fact:
> 
> "application/json+ld"
> 
> .... that is, until I was corrected by people that knew better. :)
> 
> Every now and then I go back and scan through a sea of specifications
> and mailing lists in an attempt to understand the reasoning behind the
> choice... find it (at least, that's what I keep telling myself), and
> then promptly forget because the path is so twisted and meandering.
> 
> In any case, that ship sailed long ago.

Yes indeed. And the reason for the syntax is also quite clear and easy. 
It came up with XML. For XML, there isn't only application/, there are 
also image/, message/, and model/ (see 
https://www.iana.org/assignments/media-types/media-types.xhtml), and 
font/svg+xml would also be possible even though it isn't registered 
currently.

Similar considerations apply to other suffixes, in particular also those 
related to compression schemes. Major types and suffixes are not 
hierarchical. A suffix was easier to pick out than something in the middle.

Even for json, there's model/gltf+json, so if you want to deal with all 
json, you would have to match for "/json", not for "application/json", 
in a scheme that would but what are now suffixes at the start of the 
subtype.

Regards,   Martin.

> -- manu
> 
> PS: Hi Nathan! It's been years -- hope you're well. :)
>