Subject: [Uri-review] about: scheme; Simplified Encoding Considerations

From: Joseph A Holsten <[email-masked]>
Date: Mon, 21 Sep 2009 00:52:46 -0500

URI people:

I intend to replace the current about: scheme Encoding  
Considerations[1]:

    Because many characters are not permitted with this syntax, the
    "segment" and "query" elements may contain characters from the
    Unicode Character Set [UCS] as suggested by URI [RFC3986], by first
    encoding those characters as octets to the UTF-8 character encoding
    [RFC3629]; then only those octets that do not correspond to
    characters in the unreserved set should be percent-encoded.

    By using UTF-8 encoding, there are no known compatibility issues  
with
    mapping Internationlized Resource Identifiers to about URIs  
according
    to [RFC3987].  Since about URIs do not use domain names, "ireg-name"
    conversion is unnecessary.

with the following (adapted from hixie's ws: scheme[2]):

    Characters in the "segment" or "query" parts that are excluded by  
the
    syntax defined above must be converted from Unicode to ASCII by  
first
    encoding the characters as UTF-8 and then replacing the  
corresponding
    bytes using their percent-encoded form as defined in the URI and IRI
    specifications. [RFC3986] [RFC3987]

Any objections or issues?

1: http://tools.ietf.org/html/draft-holsten-about-uri-scheme-02#section-4
2: http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol-41#section-8.1

--
Joseph Holsten
http://josephholsten.com
mailto:[email-masked]
tel:+1-918-948-6747

---

From: Julian Reschke <[email-masked]>
Date: Mon, 21 Sep 2009 09:27:07 +0200

Joseph A Holsten wrote:
> URI people:
> 
> I intend to replace the current about: scheme Encoding Considerations[1]:
> 
>    By using UTF-8 encoding, there are no known compatibility issues with
>    mapping Internationlized Resource Identifiers to about URIs according
>    Characters in the "segment" or "query" parts that are excluded by the
>    syntax defined above must be converted from Unicode to ASCII by first
>    encoding the characters as UTF-8 and then replacing the corresponding
> ...

I think the current text is clearer with respect to whether IDNA 
conversion is needed or not.

BR, Julian

---

From: Larry Masinter <[email-masked]>
Date: Mon, 21 Sep 2009 20:11:24 -0700

I'm really confused; I'm listed in the acknowlegements 
but I don't think I saw this before? Maybe there was some 
discussion of these points?

http://en.wikipedia.org/wiki/About:_URI_scheme

has a lot more useful information; you know, a 
shorter document that just referenced the Wikipedia
page would seem like it would be a lot more useful.

about:<anything>

where <anything> can be any sequence of characters,
where some common uses are listed in ....

Are there any real use cases for about:
where any of the text about encoding considerations
and equivalence matters? Or that use query parameters?

There are no examples of such in the document.

" Applications are also permitted to redirect such URIs."
This is confusing, because applications are permitted
to do anything they want, aren't they? Isn't it
just "implementation dependent" with a restriction
that it not have side effects? And if you redirect
these URIs, don't you have the issue of making sure
the redirection doesn't result in side effects?

Section 5.2 lists things as "examples" but then claims
they are "common". Perhaps these aren't "examples"
but "common usage"? Again, the wikipedia page is
more useful.

What about about:html-compat?

"The HTML representation of the URI "about:blank" MUST use the origin
   and the effective script origin as defined by HTML5 Section 5.4
   Origin [W3C.WD-html5]"

but the HTML representation of the URI "about:blank"
is not defined as something that has an origin or
an effective script origin in most deployed software,
it's just an empty resource. So this MUST doesn't
make sense in the context given.
This advice could be conditioned on the HTML interpreter
actually being compliant with html5, but then this
doesn't really belong in the registration of about:,
whose use is already widely deployed.

Larry
--
http://larry.masinter.net

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Joseph A Holsten
Sent: Sunday, September 20, 2009 10:53 PM
To: [email-masked]
Subject: about: scheme; Simplified Encoding Considerations

URI people:

---

From: Julian Reschke <[email-masked]>
Date: Tue, 22 Sep 2009 09:35:07 +0200

> whose use is already widely deployed.

...which reminds me that the normative reference on HTML5 is a problem 
in itself. It would be really great if it could be avoided.

BR, Julian