Revisiting mime-types and file extensions

Thomas Nichols nichols7 at
Wed Jun 20 05:51:04 EDT 2007

A. Pagaltzis wrote:

> * Michel Fortin <michel.fortin at> [2007-06-16 15:15]:


>> Le 2007-06-16 à 2:57, A. Pagaltzis a écrit :


>>> * Michel Fortin <michel.fortin at> [2007-06-16 01:30]:


>>>> Specifically, what happens if I change the page URL to PHP

>>>> Markdown Extra some day?


>>> Nothing. Just because people are accustomed to HTTP URIs being

>>> derenferencable to some actual page or other resource doesn’t

>>> mean they actually have to be.


>> Yes, but there is no point in using a URI in this case.



> It’s a globally unique identifier.


FWIW, the [Ruby MIME::Type library][ruby-mime-type] chooses URIs as
GUIDs. This seems a sane decision to me, since the domain registration
process guarantees uniqueness without any of the
submission/discussion/approval steps required for a more formal
approval. Having a mime type of 'text/x-markdown' and a profile URI
declared by the author of the language grammar (e.g.
"") seems an economical solution, and would follow
the pattern for [XML namespaces][xml-namespaces], Java JAXP feature
URIs[jaxp-features] and [OpenID identifiers][openid] It would allow
creation of a "Markdown Extra Plus" grammar, say, even if the current
project leads are unavailable to confirm whether
'text/x-markdown-extra-plus' has already been allocated.

I do not expect any resource to be necessarily _available_ at that URI;
if one can be retrieved, I'd expect it to be an explanatory text/html

Would there be any objections to our implementing such a scheme
(internally to Railfrog)? We're considering using - documents
can be processed by either BlueCloth or Maruku - documents can be processed by Maruku
The version number could be used in future to handle changes to the grammar.

Any suggested changes to this? Michel, would you care to propose a URI
for Markdown Extra, should anyone decide they'd like to use one?



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