RE: [xri-editors] RE: case sensitivity of XRI authorities

["Dave McAlpin" <dave.mcalpin@epokinc.com>]

But remember, we're talking about case insensitive comparisons in the XRI
authority component of an XRI. False negatives aren't a disaster. Could the
lack of locale info possibly result in a false positive? If a false
positive's possible, that's a show stopper for me. A corner case that
results in a false negative I think may be ok.

Dave

> -----Original Message-----
> From: Sakimura, Nat [mailto:n-sakimura@nri.co.jp]
> Sent: Tuesday, October 28, 2003 10:43 PM
> To: Drummond Reed; XRI Editors (E-mail)
> Subject: RE: [xri-editors] RE: case sensitivity of XRI authorities
>
>
> Sorry to be such a late comer!
>
> One concern:
>
> Unicode 4.0 case insensitivity makes sense just because of this
> particular sentence:
>
> The default casing operations are to be used in the absence of
> tailoring for particular languages
> and environments. Where a particular environment (such as a
> Turkish locale)
> requires tailoring, that can be done without violating conformance.
>
> Unicode assumes that you know the locale you are in.
> We do not know the locale we are in unfortunately, which brings
> us an extra dimension of troubles.
>
> Nat
>
> > -----Original Message-----
> > From: Drummond Reed [mailto:drummond.reed@onename.com]
> > Sent: Friday, October 24, 2003 3:11 AM
> > To: XRI Editors (E-mail)
> > Subject: RE: [xri-editors] RE: case sensitivity of XRI authorities
> >
> > My answer to Dave's question #1 is "yes". I believe
> > case-insensitivity is a good thing in XRI authority component
> > for purposes of determining equivalence for the same reasons
> > it is the in URI authority component (and even in
> > percent-encoding). I believe Mike's earlier point about
> > case-sensitivity of user names and other resources in Unix
> > will apply primarily below the XRI authority level (but I
> > could be convinced otherwise if he feels strongly about it).
> >
> > On Dave's question #2, I defer to Nat, however I did read
> > Standard Annex
> > #21 and it seemed pretty clear and comprehensive.
> >
> > Nat, what's your view?
> >
> > =Drummond
> >
> > -----Original Message-----
> > From: Dave McAlpin [mailto:dave.mcalpin@epokinc.com]
> > Sent: Thursday, October 23, 2003 11:00 AM
> > To: 'Wachob, Gabe'; Drummond Reed; 'XRI Editors (E-mail)'
> > Subject: RE: [xri-editors] RE: case sensitivity of XRI authorities
> >
> > Right, so there are really two questions.
> >
> > 1) Do we want the XRI-authority component to be
> > case-insensitive, and if so
> > 2) Is case-less matching as defined in Unicode 4.0 good enough?
> >
> > The second is probably a question for Nat.
> >
> > Dave
> >
> > -----Original Message-----
> > From: Wachob, Gabe [mailto:gwachob@visa.com]
> > Sent: Thursday, October 23, 2003 10:44 AM
> > To: 'Dave McAlpin'; 'Drummond Reed'; 'XRI Editors (E-mail)'
> > Subject: RE: [xri-editors] RE: case sensitivity of XRI authorities
> >
> > +1 to Dave's proposal if the feeling is strong towards case
> > insensitivity in
> > the authority part.
> >
> > Is there anything broken about applying that part of Unicode
> > 4 to our current spec?
> >
> >         -Gabe
> >
> > > -----Original Message-----
> > > From: Dave McAlpin [mailto:dave.mcalpin@epokinc.com]
> > > Sent: Thursday, October 23, 2003 10:17 AM
> > > To: 'Drummond Reed'; 'XRI Editors (E-mail)'
> > > Subject: RE: [xri-editors] RE: case sensitivity of XRI authorities
> > >
> > >
> > > That's a good summary of my proposal, although I think we'd
> > probably
> > > cite section 3.13 of the Unicode 4.0 spec rather than
> > Unicode Standard
> > > Annex #21.
> > >
> > > Dave
> > >
> > > -----Original Message-----
> > > From: Drummond Reed [mailto:drummond.reed@onename.com]
> > > Sent: Thursday, October 23, 2003 10:05 AM
> > > To: XRI Editors (E-mail)
> > > Subject: [xri-editors] RE: case sensitivity of XRI authorities
> > >
> > > [Note: I moved this discussion to the Editor's list for
> > archiving. I
> > > also copied in Dave's second response re Unicode case rules so it
> > > would all be in one place. =DSR]
> > >
> > > Okay, so Dave's argument, as I understand it now, is that:
> > >
> > > A) We should specify full Unicode 4.0 caseless matching for the XRI
> > > authority segment because this should be true of ALL XRI authority
> > > identifiers, this being the global portion of an XRI that
> > uses an XRI
> > > authority.
> > >
> > > b) We should not specify any case insensitivity rules for
> > the rest of
> > > an XRI path because that should be up to each authority.
> > >
> > > To further summarize, this means that we are proposing that the 1.0
> > > specification will say that there are only 3 places in which
> > > case-insensitivity applies to ALL XRIs:
> > >
> > > 1) Percent-encoding.
> > >
> > > 2) URI authority segments using the rules specified in RFC 2396.
> > >
> > > 3) XRI authority segments as specified in Unicode Standard Annex #21
> > > (http://www.unicode.org/reports/tr21/tr21-5.html)
> > >
> > > Does everyone agree with this proposal?
> > >
> > > =Drummond
> > >
> > >
> > > ***DAVE'S ADDITIONAL RESPONSE***
> > >
> > > Incidentally, the new Unicode 4.0 spec does describe caseless
> > > matching.
> > > The
> > > text was incorporated from
> > > http://www.unicode.org/reports/tr21/tr21-5.html.
> > > There are two or three corner cases that are problematic,
> > but the vast
> > > majority of situations are covered.
> > >
> > >
> > > -----Original Message-----
> > > From: Dave McAlpin [mailto:dave.mcalpin@epokinc.com]
> > > Sent: Thursday, October 23, 2003 8:16 AM
> > > To: Drummond Reed; Wachob, Gabe; Lindelsee, Mike; Nat Sakimura
> > > (E-mail); Peter C Davis (E-mail)
> > > Subject: RE: case sensitivity of XRI authorities
> > >
> > > Right, but that only addresses my problem if the global
> > namespaces are
> > > case-insensitve, which puts us right back where we started.
> > >
> > > Imagine DNS names were case sensitive. You visit a page
> > with a link to
> > > http://www.Microsoft.com. You'd like to visit Microsoft's
> > website so
> > > you click the link. Unfortunately, www.Microsoft.com is a malicious
> > > site (as was the site that contained the link). You really
> > wanted to
> > > go to http://www.microsoft.com but were tricked into going
> > to a rogue
> > > site because you, as a user, didn't know the proper case of
> > the target
> > > site. That would be bad. It seems to me that case sensitive
> > > comparisons in the XRI-authority segment are bad for
> > exactly the same
> > > reason.
> > >
> > > With that said, I AM sensitive to the concern about
> > > internationalization and the message it sends to treat English
> > > language characters differently.
> > > Let
> > > me ask the question this way - if there was a good
> > algorithm for doing
> > > case insensitive comparisons across the entire Unicode range, would
> > > you guys support case-insensitivity in the XRI-authority?
> > >
> > > Dave
> > >
> > > > -----Original Message-----
> > > > From: Drummond Reed [mailto:drummond.reed@onename.com]
> > > > Sent: Wednesday, October 22, 2003 9:42 PM
> > > > To: Dave McAlpin; Wachob, Gabe; Lindelsee, Mike; Nat Sakimura
> > > (E-mail);
> > > > Peter C Davis (E-mail)
> > > > Subject: RE: case sensitivity of XRI authorities
> > > >
> > > >
> > > > Dave,
> > > >
> > > > I find your argument compelling too. I agree that the authority
> > > > component is a special case, that could be treated
> > differently that
> > > the
> > > > rest of the XRI.
> > > >
> > > > The biggest problem I have with saying XRI authorities should be
> > > > case-insensitive is that XRI authorities, unlike URI authorities,
> > > allow
> > > > the full IRI character range (for which I think we all
> > > agree we cannot
> > > > define case insensitive rules, unless we can adopt
> > > something specified
> > > > by Unicode).
> > > >
> > > > If that's the case, then singling out the ASCII range for
> > > > case-insensitivity in XRI authorities seems, well, a little
> > > insensitive
> > > > (pardon the pun ;-)
> > > >
> > > > An alternative is to say that BECAUSE XRI authorities are
> > > > internationalized, case insensitivity is not specified at
> > > the level of
> > > > the XRI spec, but can be adopted by any particular XRI authority.
> > > >
> > > > How do folks feel about that?
> > > >
> > > > =Drummond
> > > >
> > > > -----Original Message-----
> > > > From: Dave McAlpin [mailto:dave.mcalpin@epokinc.com]
> > > > Sent: Wednesday, October 22, 2003 6:08 PM
> > > > To: Drummond Reed; 'Wachob, Gabe'; 'Lindelsee, Mike'
> > > > Subject: RE: case sensitivity of XRI authorities
> > > >
> > > > You're right that this wasn't my original position. I'm
> > > willing to be
> > > > outvoted, but consider the following.
> > > >
> > > > 1) The authority segment is special, primarily because we
> > define the
> > > > resolution mechanics for it. I don't think it's
> > > inconsistent to define
> > > > equivalence rules for it and be silent about
> > non-authority segments.
> > > >
> > > > 2) In fact, because we define resolution, I think we're obliged to
> > > give
> > > > guidance about case sensitivity in the authority component,
> > > one way or
> > > > the
> > > > other.
> > > >
> > > > 3) The authority component is the piece a user or
> > programmer is most
> > > > likely to guess. That's certainly true for domain names
> > and I'll bet
> > > > it's equally true for xri authorities.
> > > >
> > > > 4) If the authority component is case insensitive, guessing is
> > > > dangerous.
> > > > For example, xri:@Nordstrom and xri:@nordstrom will resolve
> > > differently
> > > > (possibly to the same network endpoint, but they wouldn't be
> > > equivalent
> > > > by
> > > > definition). That means that Nordstrom either needs to
> > register all
> > > > possible case distinctions a user might reasonably guess
> > or else be
> > > subject to
> > > > spoofers. I think both options are bad.
> > > >
> > > > My preference is
> > > >
> > > > A) Percent-encoding is case INSENSITIVE.
> > > > B) Both URI-authorities and XRI-authorities are case INSENSITIVE.
> > > > C) Everything else is defined by the naming authority
> > that controls
> > > the
> > > > segment or subsegment in question (i.e. by its immediate parent).
> > > >
> > > > Dave
> > > >
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: Drummond Reed [mailto:drummond.reed@onename.com]
> > > > Sent: Wednesday, October 22, 2003 12:58 PM
> > > > To: Wachob, Gabe; Lindelsee, Mike; Dave McAlpin
> > > > Subject: RE: case sensitivity of XRI authorities
> > > >
> > > > Ah, good, at least I think we're all on the same page now. Mike's
> > > > argument about case sensitivity convinced me that C was the
> > > best path
> > > > for XRI authorities, even though it's different than URI
> > > authorities.
> > > My
> > > > reasoning is that by not requiring in the spec for XRI
> > > authorities, we
> > > > keep the option open for specific XRI authorities to
> > "narrow" their
> > > > namespace to case sensitive, but that the spec itself
> > will be broad
> > > > enough to allow for case-insensitive authorities.
> > > >
> > > > So, Dave, it seems that Gabe, Mike, and I would all prefer
> > > to adopt C.
> > > > What's your stance?
> > > >
> > > > =Drummond
> > > >
> > > > -----Original Message-----
> > > > From: Wachob, Gabe [mailto:gwachob@visa.com]
> > > > Sent: Wednesday, October 22, 2003 12:33 PM
> > > > To: Drummond Reed; Wachob, Gabe; Lindelsee, Mike; Dave McAlpin
> > > > Subject: RE: case sensitivity of XRI authorities
> > > >
> > > > We are out of sync!
> > > >
> > > > C) is NOT agreed to. I like the position stated in C, but
> > I think it
> > > the
> > > > opposite of what we've agreed to.
> > > >
> > > > I gather that Mike L would follow whatever decision we made, so I
> > > wonder
> > > > what Dave's position is on case-sensitivity of
> > XRI-authorities. I'd
> > > like
> > > > to adopt the position in C)
> > > >
> > > >         -Gabe
> > > >
> > > > > -----Original Message-----
> > > > > From: Drummond Reed [mailto:drummond.reed@onename.com]
> > > > > Sent: Wednesday, October 22, 2003 12:29 PM
> > > > > To: Wachob, Gabe; Lindelsee, Mike; Dave McAlpin
> > > > > Subject: RE: case sensitivity of XRI authorities
> > > > >
> > > > >
> > > > > First, my bad. My message said "So the conclusion is
> > > case-sensitivity
> > > > > only for percent-encoding and URI-authorities" and what I meant
> > > > > was case INsensitivity for these. Sorry, just not enough coffee
> > > > > this morning ;-)
> > > > >
> > > > > Second, I'm still unclear from Gabe's message below. So
> > let me put
> > > it
> > > > > this way. I believe what we agreed on was that:
> > > > >
> > > > > A) Percent-encoding is case INSENSITIVE.
> > > > >
> > > > > B) URI-authorities are case INSENSITIVE.
> > > > >
> > > > > C) Everything else, including XRI-authorities, are case
> > SENSITIVE.
> > > > > (If a particular XRI authority decides to apply case
> > INSENSITIVITY
> > > > > to a namespace under their control, that's their perogative,
> > > but the spec
> > > > > will not require that.)
> > > > >
> > > > > Does everyone agree?
> > > > >
> > > > > =Drummond
> > > > >
> > > > > -----Original Message-----
> > > > > From: Wachob, Gabe [mailto:gwachob@visa.com]
> > > > > Sent: Wednesday, October 22, 2003 12:03 PM
> > > > > To: Drummond Reed; Lindelsee, Mike; Wachob, Gabe; Dave McAlpin
> > > > > Subject: RE: case sensitivity of XRI authorities
> > > > >
> > > > > Wait guys!
> > > > >
> > > > > We're getting a little confused here.
> > > > >
> > > > > First of all, lets be clear about case-sentivity vs.
> > > INsensitivity.
> > > > >
> > > > > 1) I think we all agree that domain names (URI
> > > authorities) are case
> > > > > INSENSITIVE and there is nothing broken about this.
> > > > >
> > > > > 2) The issue is about non-domain names (XRI authorities) - for
> > > example
> > > > > xri:+foo and xri:+Foo. Currently they are specified as case
> > > > > INSENSITIVE (meaning that US-ASCII characters as
> > case-insensitive,
> > > but all other
> > > > > characters, including, for example, Ñ and ñ are treated
> > > > > differently - ie case SENSITIVE). I'm not convinced this is
> > > > > required for URI
> > > alignment
> > > > > and in fact, I think its a bad idea given the Ñ/ñ situation I
> > > > > mentioned in a previous email.
> > > > >
> > > > > 3) And %-escaped characters are equivalent whether or
> > not the hex
> > > > > digits are upper or lower case (ie %b0 is the same as %B0).
> > > > >
> > > > > Is this what everybody is agreeing to?
> > > > >
> > > > >         -Gabe
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Drummond Reed [mailto:drummond.reed@onename.com]
> > > > > > Sent: Wednesday, October 22, 2003 11:48 AM
> > > > > > To: Lindelsee, Mike; Wachob, Gabe; Dave McAlpin
> > > > > > Subject: RE: case sensitivity of XRI authorities
> > > > > >
> > > > > >
> > > > > > Thanks, Mike. I recalled that your reasoning convinced me
> > > > > and it still
> > > > > > does. So the conclusion is case-sensitivity only for
> > > > > percent-encoding
> > > > > > and URI-authorities. XRI authorities can then of course
> > > > > decide on the
> > > > > > rules for their individual namespaces, but the spec will say
> > > nothing
> > > > > > about this.
> > > > > >
> > > > > > Done.
> > > > > >
> > > > > > =Drummond
> > > > > >
> > > > > > -----Original Message-----
> > > > > > From: Lindelsee, Mike [mailto:mlindels@visa.com]
> > > > > > Sent: Wednesday, October 22, 2003 10:30 AM
> > > > > > To: Drummond Reed; Wachob, Gabe; Dave McAlpin; Lindelsee, Mike
> > > > > > Subject: RE: case sensitivity of XRI authorities
> > > > > >
> > > > > > I was just reviewing that thread and Dave remembered
> > the result
> > > > > > of that discussion correctly.  We left it that
> > percent encoding
> > > > > > and URI-authorities would be case-insensitive.  I'm still not
> > > > > > convinced that URI-authorities need always be
> > case-insensitive
> > > > > > (except in the
> > > case
> > > > > > where we are being backwards compatible with DNS
> > names), but am
> > > > > > happy to accept the wisdom of the group on this. ;)
> > > > > >
> > > > > > My reasoning, btw, was (imho) not particularly strong, but
> > > > > still makes
> > > > > > sense to me.  That is, unicode issues,
> > case-sensitivity in many
> > > > > > filesystems, and case-sensitivity in account/resource
> > naming all
> > > > > > lead me to feel that it would be more flexible and
> > > > > > forward-looking to not limit ourselves by declaring all of an
> > > > > > XRI (or even just the
> > > > > Authority part)
> > > > > > case-insensitive.
> > > > > >
> > > > > > Mike
> > > > > >
> > > > > >
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Drummond Reed [mailto:drummond.reed@onename.com]
> > > > > > > Sent: Tuesday, October 21, 2003 6:48 PM
> > > > > > > To: Wachob, Gabe; Dave McAlpin; Lindelsee, Mike
> > > > > > > Subject: RE: case sensitivity of XRI authorities
> > > > > > >
> > > > > > >
> > > > > > > I know I'm late on this but I though Mike persuaded
> > > us all that
> > > > > > > everything should be case sensitive. Mike, what was your
> > > > > > argument, and
> > > > > > > where did we end up after you made that argument?
> > > > > > >
> > > > > > > =Drummond
> > > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Wachob, Gabe [mailto:gwachob@visa.com]
> > > > > > > Sent: Tuesday, October 21, 2003 1:04 PM
> > > > > > > To: 'Dave McAlpin'; Wachob, Gabe; Drummond Reed;
> > > Lindelsee, Mike
> > > > > > > Subject: RE: case sensitivity of XRI authorities
> > > > > > >
> > > > > > > I haven't changed the text as it is now, lets see if we get
> > > > > > > comments on it. I would guess their (URI) brokeness
> > has to do
> > > > > > > with
> > > > > the DNS case
> > > > > > > insensitivity (they didn't think anyone else would
> > > come up with
> > > a
> > > > > > > different way of naming authorities i bet you).
> > > > > > >
> > > > > > >     -Gabe
> > > > > > > -----Original Message-----
> > > > > > > From: Dave McAlpin [mailto:dave.mcalpin@epokinc.com]
> > > > > > > Sent: Tuesday, October 21, 2003 12:36 PM
> > > > > > > To: 'Wachob, Gabe'; 'Drummond Reed (E-mail)';
> > > 'Lindelsee, Mike'
> > > > > > > Subject: RE: case sensitivity of XRI authorities In the
> > > > > > > previous discussion, we decided to leave it broken
> > > > > > with respect
> > > > > > > to internationalization because Nat said it was impossible
> > > > > > to come up
> > > > > > > with a generic, case insensitive comparison
> > algorithm. At the
> > > > > > > same time, there was support for case insensitive
> > comparison,
> > > > > > > so we decided not to throw the baby out with the
> > bathwater and
> > > > > > > leave it enabled for the ALPHA production. Another way of
> > > > > > > looking at it is that we just followed 2396's lead on the
> > > > > > > authority portion.
> > > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Wachob, Gabe [mailto:gwachob@visa.com]
> > > > > > > Sent: Tuesday, October 21, 2003 12:31 PM
> > > > > > > To: Dave McAlpin (E-mail); Drummond Reed (E-mail);
> > Lindelsee,
> > > Mike
> > > > > > > Subject: case sensitivity of XRI authorities
> > > > > > >
> > > > > > > What was the resolution on this topic?
> > > > > > >
> > > > > > > We have the language in there about case
> > insensitive for alpha
> > > > > > > characters.
> > > > > > >
> > > > > > > Is this what we concluded? I can't find a record in email.
> > > > > > >
> > > > > > > This is a little odd, of course, because for languages
> > > > > like Spanish,
> > > > > > > xri:+pequeño and xri:+Pequeño are the same but
> > > xri:+pequeño and
> > > > > > > xri:+PEQUEÑO are different. That smacks of indifference to
> > > > > > > internationalization concerns (its odd because
> > whether or not
> > > the
> > > > > > > upcasing/downcasing changes equivalence depends on which
> > > > > > > characters you use).
> > > > > > >
> > > > > > > My vote is against case insensitivity even in the
> > > > > > "authority" part, at
> > > > > > > least as a rule that applies to all xris. We could
> > > say that, for
> > > > > > > example, within the + namespace, the naming
> > > authorities are case
> > > > > > > insensitive (with whatever definition of case insensitivity
> > > > > > we decide
> > > > > > > makes sense), but it strikes me as broken to declare case
> > > > > > > insensitivity the way we have done it.
> > > > > > >
> > > > > > >     -Gabe
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > >
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