# Re: what good is a URL without type information?

John Curran (jcurran@nic.near.net)
Mon, 25 Oct 1993 01:17:20 -0400

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- In reply to: Larry Masinter: "what good is a URL without type information?"

    Message-Id: <9310250517.AA21550@mocha.bunyip.com>

    To: Larry Masinter <masinter@parc.xerox.com>

    Subject: Re: what good is a URL without type information?

    In-Reply-To: Your message of Sat, 23 Oct 1993 03:28:29 -0700.

                 <93Oct23.032838pdt.2795@golden.parc.xerox.com>

    Date: Mon, 25 Oct 1993 01:17:20 -0400

    From: John Curran <jcurran@nic.near.net>

--------
From: Larry Masinter <masinter@parc.xerox.com>
Subject: what good is a URL without type information?
Date: Sat, 23 Oct 1993 03:28:29 PDT

I can imagine doing without everything else that's been categorized as
meta-information except for the type information. The type of a data
object seems necessary to do even the most minimal interpretation.

At this point, I've come the full circle on "type" information in URLs...
(meaning I would probably ask to have them put in the URL, given a chance
to "start over". Before the cry to do this reaches full fury, read on.)

The one reason (that I deperately cling to) in support of the
separation of URLs and type information goes as follows:
If the type information becomes part of the URL, then it really
should be used when providing a URL for retrieval. Taken to
extremes, this would have the user entering the type information
as part of the URL in a pop-up window. If the user enters the
wrong type, what happens? I see lots of users sick of entering
"text/plain"...

Now, if the type information is returned in association with the
URL, then the URL is unencumbered by information which is not
necessary for retrieval. A user can enter a URL and the client
can either get the type information as part of the retrieval method
(sure...) or it can (in the worst case) use heuristics to determine.
Perhaps we just need more access methods which supply the type
information of the retrieved object? For example, it would be
possible to define an IAFA compliant ftp archives as a separate
access method since the IAFA templates include type information.
(An IAFA compliant FTP server truly resembles an information vault,
rather than a public data heap.) Likewise, MIME formatting often
results in explicit typing, so URLs pointing to these resources
would contain redundant (and potentially conflicting) type information.

Practically speaking, there's little gained and significant functionality
lost by not including "type" information in URLs. One of the few positive
side effects is that we may see more rapid adoption of URNs (given that the
URN resolution process supplies both URLs and strong type information :-)

/John

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