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Re: Getting full URI to the server

From: Brian Behlendorf <brian@wired.com>
Date: Sun, 12 Feb 1995 15:18:46 -0800 (PST)
To: "Roy T. Fielding" <fielding@avron.ICS.UCI.EDU>
Cc: Mike Cowlishaw <mfc@vnet.ibm.com>, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Message-Id: <Pine.BSD.3.91.950212150612.17150A-100000@get.wired.com>
On Sun, 12 Feb 1995, Roy T. Fielding wrote:
> Note that it has no other advantage, as the only non-distinguishable link
> to that server is the root.  So, the next question is what would adding
> a "host" header (or the equivalent) achieve?  Well, we already know that
> existing clients do not support such a header, and it would take quite a
> bit of time to get them to, so the server cannot rely on its existence
> to provide the switching mechanism among the intended home pages.  

Fortunately, the changes on each side are really minor.  In fact there 
are no changes required on the server side if the request is funneled to 
a CGI script (where one would look for the "HTTP_HOST" environment 
variable).

So, client folk, it's up to you.... do I hear any takers?

> The final question is: Does the additional functionality justify the cost
> and effort of including the Host header in the 1.1 standard, with the
> necessarily strong recommendation that it be included with all requests?
> 
> In my opinion, the answer to this last question is NO.  Allowing a server
> to automatically choose the root URL from among the roots associated with
> multiple vanity hostnames is simply not a sufficiently important piece of
> functionality to justify its inclusion as part of the 1.x standard.

It seems to me to be the *definition* of something easy to add - if
semantically or systemically there are no objections to it, then browser
authors should be encouraged to take 10 minutes to add it.  In fact, I
don't even see a terrible upgrade issue - if there's a host with multiple 
vanity hostnames going to it, and it doesn't get a Host: header, it can 
give a default page with a list of all pages, whereas if it does get a 
Host: header it can give the appropriate vanity home page.  

In some respects this gets into the need for an HTTP user agent 
definition, possibly even a numbered-level classification scheme.

> In order for such a feature to be added to the protocol, it will have to
> justify itself externally to the standards process.  In other words, if
> a sufficient number of WWW browsers and servers implement a header with the
> above syntax and semantics, that header will be added to the specification.
> When in doubt, bottom-up standardization is better than top-down.

Agreed.  Now if only I could find my way around X Mosaic source code...

	Brian

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brian@hotwired.com  brian@hyperreal.com  http://www.hotwired.com/Staff/brian/
Received on Sunday, 12 February 1995 15:22:33 EST

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