Re: CID: and MID: URL schemes

Ed Levinson (elevinso@Accurate.COM)
Fri, 03 Nov 1995 10:12:50 -0500


Message-Id: <9511031513.AA08203@Accurate.COM>
To: Larry Masinter <masinter@parc.xerox.com>
Cc: elevinso@Accurate.COM, uri@bunyip.com, ietf-822@list.cren.net,
Subject: Re: CID: and MID: URL schemes 
In-Reply-To: Your message of "Thu, 02 Nov 1995 21:29:21 PST."
             <95Nov2.212930pst.2733@golden.parc.xerox.com> 
Date: Fri, 03 Nov 1995 10:12:50 -0500
From: Ed Levinson <elevinso@Accurate.COM>

To put the special character issue more succintly:

	id-spec := local-part "@" addr-spec
		   ; Globally unique
		   ; Characters in [RFC1738] unreserved
		   ; must be escaped with [RFC1738] escape

That says it all!  The words trying to explain the "restriction" can
be eliminated.  Latter on the draft would say

	To transform a cidurl or midurl into a valid content-id or
	message-id, replace the [RFC1738] escape sequences by the
	actual character and surround the resultant string with the
	enclosing brackets, i.e.,

		content-id := "<" raw-spec ">"

		message-id := "<" raw-spec ">"

		raw-spec:  := id-spec
				; escape seqeuences replaced with
				; actual characters

Seems pretty straigtforward to me.  Systems are free to %hex encode
whatever they want.

Thanks.../Ed

On Thu, 02 Nov 1995 21:29:21 PST Larry Masinter wrote:
> >       where id-spec is a restricted form of "addr-spec" as defined
> >       in [RFC822] and hostname and uchar are defined in [RFC1738,
> >       sec 3.1].  The purpose of the restriction on addr-spec is to
> >       eliminate special characters from the cid URL.  Such
> >       characters, if required, can be encoded using the [RFC1738]
> >       %xx hex encoding escape mechanism included in uchar.
> 
> This still seems awkward. The problem is that the RFC 822 productions
> allow unsafe characters in all parts of the IDs, and have special
> quoting and bracketing rules. You really have two choices: one is to
> include the full production for id-spec in parallel with the
> production of addr-spec in RFC 822, but then allow (%hex)-encoding of
> the individual terminal elements, or else just to define
> 
> id-spec to be (%hex)-encoded addr-spec, and leave out the 
> 
> 	id-spec = local-part "@" hostname
> 
> 
> production completely. Why NOT allow "@" to be URL-encoded, too?
> These things aren't really going to be parsed.
>