W3C home > Mailing lists > Public > uri@w3.org > February 2004

Host header (was uri handling of hosts is too restrictive)

From: Stefan Eissing <stefan.eissing@greenbytes.de>
Date: Mon, 16 Feb 2004 09:49:02 +0100
Message-Id: <F86774E7-605C-11D8-9873-00039384827E@greenbytes.de>
To: uri@w3.org


Am 16.02.2004 um 05:56 schrieb Roy T. Fielding:
>> But for the question of whether percent-escapes are allowed in host
>> names, I don't think that argument holds.  Implementations are not
>> interoperable for that case.  Faced with http://jos%C3%A9.net/, some
>> applications percent-decode the name before calling the resolver, and
>> some pass jos%C3%A9.net literally to the resolver.  The latter group 
>> of
>> applications don't include a codepath for performing percent-decoding 
>> on
>> host names because RFC-2616 and RFC-2396 promise that it's not 
>> necessary
>> (RFC-2616 promises that the name is a host, not a reg_name, and 
>> RFC-2396
>> promises no percent-escapes in host names).
>
> They don't need such a codepath.  They will fail as "not found", which
> is all they need to do to retain interoperability during name 
> resolution.

This is not directly related to URIs, but how does the escaping/punying 
of
hostnames affect the HTTP host header? As an implementor of HTTP client
code, I wonder in which format I have to send the header value.

At the moment I would just use the hostname as it appears in the URI. 
In order
for that to work, both the resolver and the HTTP server code would have
to work the same way for the request to go through. It's probably best 
to
leave the equality check of different hostname spellings up to the 
server. But
until all servers are upgraded, is there anything the client can do?

Best regards, Stefan 
Received on Monday, 16 February 2004 03:50:42 UTC

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