Revisiting mime-types and file extensions

[Sam Angove]

On 6/15/07, Thomas Nichols <nichols7 at googlemail.com> wrote:

> Using the "experimental" types indicated by 'x.' and 'x-' might also be

> a possibility in the short term, but is not recommended; a properly

> registered mime type in the main tree would provide a clear

> standardisation. Is this important enough to anyone else to warrant an

> attempt to register a name? Or should we just create a solution specific

> to our own problem domain?


I expect that submitting something acceptable to the IETF standards
track would be rather a lot of work and probably fail. The lack of
clear standardisation is an issue regardless, and would have to be
resolved *before* submission.

For the vendor tree, the guidelines do qualify "well-known producer",
"IANA-approved designation of the producer's name", etc. It's not
clear that `vnd.markdown` is appropriate. Even if it is, what would it
*mean*?

Right now we really have `text/prs.gruber.markdown`,
`text/prs.fortin.php-markdown-extra` etc. etc. "Markdown"
implementations generally implement something close to the former, but
there are ambiguous edge-cases so who knows for sure? Proposals for a
normative grammar went nowhere.

`text/x-markdown` seems a reasonable media-type to encompass the whole
murky, underspecified lot of them. Specific extensions/implementations
could be indicated with an optional parameter, like:

    text/x-markdown;
profile="http://www.michelf.com/projects/php-markdown/extra/"

That seems better than requiring a separate media type for every
extension. YMMV.

As an aside, I think the reStructuredText case is one to avoid
repeating: it has an IANA registration as `text/prs.fallenstein.rst`,
but its highest-profile [user][1] prefers `text/x-rst`.

[1]: http://www.python.org/dev/peps/pep-0012/