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microid - Re: [Microid] Augmented Backus-Naur Form Scheme issues?

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  • From: Fred Stutzman <fred AT metalab.unc.edu>
  • To: Peter Saint-Andre <stpeter AT jabber.org>
  • Cc: microid AT lists.ibiblio.org
  • Subject: Re: [Microid] Augmented Backus-Naur Form Scheme issues?
  • Date: Wed, 15 Aug 2007 20:31:40 -0400 (EDT)

On Wed, 15 Aug 2007, Peter Saint-Andre wrote:

Yaniv Golan wrote:
Oops. I actually think the "+" thing was my proposal, and therefore my
fault. Sorry about that :)

No worries. I should have checked RFC 3986. :)

Because there are no current schemes using "+",

There are no current registered schemes. The only scheme I use with a
"+" in it is svn+ssh (but it is not registered with the IANA).

I vote +1 for option
#2 (Provide guidance for handling of "+"), and I suggest specifying
that the schema name should be URL-encoded, so that "+" will become
"%2B".

So on the off chance that someone uses svn+ssh as input to a MicroID,
the resulting MicroID would be something like:

mailto+svn%2Bssh:sha1:some-long-hash-here

That seems acceptable.

/psa

+1

-Fred




Yaniv

--
Yaniv Golan
CTO, Yedda | http://yedda.com
e: yaniv AT yedda.com | m: +972-54-4-548-249 | my yedda:
http://yedda.com/people/9512186217351




-----Original Message-----
From: microid-bounces AT lists.ibiblio.org [mailto:microid-
bounces AT lists.ibiblio.org] On Behalf Of Peter Saint-Andre
Sent: Wednesday, August 15, 2007 12:45 AM
To: Brian Suda
Cc: microid AT lists.ibiblio.org
Subject: Re: [Microid] Augmented Backus-Naur Form Scheme issues?

Brian Suda wrote:
i did a quick search through the archives and didn´t find
anything
http://www.google.is/search?hl=is&client=firefox-
a&rls=org.mozilla%3Aen-
US%3Aofficial&hs=Q5N&q=site%3Ahttp%3A%2F%2Flists.ibiblio.org%2Fpi
permail%2Fmicroid%2F+scheme&btnG=Leita&lr=
Can some one confirm that this is not actually an issue, or
that it
doesn´t matter that it is?

According to the scheme:
inputs = scheme "+" scheme
scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
; a URI scheme name (e.g., mailto)

you can have multiple schemes separated by a + symbol, but the
scheme
itself can have a + in it. For example:

svn+ssh as one scheme, concatenated + with a second scheme,
https
that would be svn+ssh+https, how would you know that is svn+ssh
and
not ssh+http? or is that even an issue?
That is a good catch. Section 3.1 of RFC 3986 defines scheme as
follows:

scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )

So you're right that "+" is allowed in the scheme name. Clearly
we did
not check the URI syntax when we defined the MicroID syntax, and
a quick
check of the IANA registry would have revealed no schemes with
"+" in
the name:

http://www.iana.org/assignments/uri-schemes.html

We should have chosen a character that's not allowed in "scheme",
such
as "_".

But I'm not sure what to do about it now. We could:

1. Change the separator to "_" or somesuch.

Pro: Conforms to RFC 3986.
Con: Breaks existing implementations.

2. Provide guidance for handling of "+".

Pro: Doesn't break existing implementations.
Con: Potentially confusing; does not conform to RFC 3986.

The spec writer in me likes (1), but the documentation guy in me
prefers
(2) since I really don't like to break existing implementations.

Peter

--
Peter Saint-Andre
https://stpeter.im/







--

Fred Stutzman
919-260-8508
ibiblio.org/fred
fred AT metalab.unc.edu

Co-Founder and Developer, ClaimID.com
Ph.D. Student and Research Fellow, SILS UNC-Chapel Hill


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