[Microid] Augmented Backus-Naur Form Scheme issues?

Fred Stutzman fred at metalab.unc.edu
Wed Aug 15 20:31:40 EDT 2007


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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