# Re: questions on URL draft

Daniel W. Connolly (connolly@hal.com)
Mon, 11 Jul 1994 07:32:44 -0500

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    Message-Id: <9407111232.AA05269@austin2.hal.com>

    To: masinter@parc.xerox.com

    Subject: Re: questions on URL draft

    In-Reply-To: Your message of "Sun, 10 Jul 1994 15:50:14 PDT."

                 <94Jul10.155019pdt.168962@nebula.parc.xerox.com>

    Date: Mon, 11 Jul 1994 07:32:44 -0500

    From: "Daniel W. Connolly" <connolly@hal.com>

First, I might be mistaken but my working definition of reserved
is "it has different meaning when escaped," whereas unsafe means
"it has the same meaning escaped and unescaped, but it is known
to be corrupted in some transports."

In message <94Jul10.155019pdt.168962@nebula.parc.xerox.com>, Larry Masinter wri
tes:

>1. Add ">" to the list of characters that are `universally reserved'
> and must be encoded in all URLs). [Used for terminating <>]
unacceptable. You can call ">" unsafe, but unless you say what
the special semantics are, I don't think it should be reserved.

I think <URL:url> was a bad choice for plain-text delimiters.
It's already overloaded with <sgml-tag> and <message-id>.

I suggest "url" .

>2. Add "<", ">", and """ (doublequote) to the list of characters
> that are universally reserved. [as with 1, but be safe]
same as #1.

>3. Remove `wais:' scheme from this draft. [not well enough defined?]
acceptable

[I'm having this trouble with the HTML spec too -- what do you do
with the stuff that you know is out there, but it's not clear how
it really works or that it works consistently at all?

Perhaps an appendix with Proposed things, or a Rationale or
some such would be a good place for things like this.]

>4. Add `local-file:<path>' as a URL that references a local file.
> [one opinion]
preferable, provided it has a syntax like #6 and #7 below, i.e.
the syntax includes a hostname. The spec should note that this
scheme doesn't really have an internet-wide semantic, as the
methods for accessing files varies from system to system.

>5. Add `file:<path>' as a URL that references a local file. [closer
> to current practice]
acceptable, but I don't like it.

>6. Add `file://<host>/<path>' as a URL that references a local file
> when referenced from <host>. [as per TimBL]
acceptable.

>7. Include `file://localhost/<path>' in file URLs. [as per TimBL]
acceptable.

>8. Add `&' as a `reserved' character. [used in forms response]
acceptable, but ?name=val&name2=val2 is redundant when we
have ?name=value;name=value

>9. Add `&' as a `reserved' character, and describe its use in the
> URLs that result from encoding the value of HTML forms. [more
> writing]
unacceptable.

>10. Assert that no new URL scheme can reserve any characters that are
> not listed as `reserved' in this document. [allows gateways
> to know what can be escaped without loss of semantics; restricts
> future schemes as to which chars can be reserved]
preferable

>11. Add an Appendix B that describes `relative URLs' in this document.
acceptable. But as long as we don't do anything that conflicts
with the practice of 'relative URLs' I don't think this document needs
to specify that practice.

Note, in particular that the practice of 'relative URLs' implies
the use of '/' as a hierarchical separator in all schemes, current
and future.

>12. Move the "URL:" prefix requirement to the (first) Appendix as a
> recommendation for URLs `in plain text'.
preferable

>13. Assert that `scheme' names are case insensitive (e.g., HTTP: is
> equivalent to http:). [I think we discussed this but don't
> remember a consensus]
acceptable, but just barely.

>14. Limit `scheme' names to lowercase ASCII letters, digits, plus,
> hyphen and underscore, with no encoding. [as proposed]
preferable (get rid of plus, though, and perhaps allow period)

>15. Remove the recommendation for using "x-" scheme names. [as proposed]
Hmm... undecided. I'd like to see the mechanism by which new names
are introduced if this recommendation is removed.

>17. add a mailserver: URL to this document, which corresponds to
> message/external-body with the "phantom body" URL encoded.
> (if there is some consensus for this, we will need to define
> the syntax). [as proposed]
preferable. (I think it's called mail-server in the MIME spec.)

Syntax proposal:
mail-server://mailbox@domain?subject=xxx;body=yyy

>18. Call it 'mail:' instead of 'mailserver:'. [alternative list]
unacceptable.

>19. Identify afs:, mid:, cid:, and other scheme prefixes that have
> been mentioned but not specified here. (including tn3270, rlogin
> if not reinstated). [really a style issue]
acceptable.

>20. Put back in `tn3270' URLs in this document. [taken out without
> clear sense of consensus]
acceptable, but just barely.

>21. Put back in `rlogin:' URLs in this document. [ditto]
unacceptable

>22. Remove "#" as a character that is universally reserved, and
> instead only reserve it in http, ftp, gopher, news. [universially
> reserved without much discussion]
unacceptable. (conflicts with #10 and #11)

>
>

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