W3C home > Mailing lists > Public > public-wai-ert@w3.org > October 2006

Re: Design problem with "HTTP vocabulary in RDF"

From: Johannes Koch <johannes.koch@fit.fraunhofer.de>
Date: Tue, 17 Oct 2006 09:41:21 +0200
Message-ID: <45348921.7030707@fit.fraunhofer.de>
To: ERT group <public-wai-ert@w3.org>

Hi Charles

Charles McCathieNevile schrieb:
>> Assuming we have two content-encodings (first gzip, then compress), 
>> the HTTP response would contain the header:
>>
>>    Content-Encoding: gzip, compress
>>
>> in RDF/XML:
>>
>>    <http:content-encoding>gzip, compress</http:content-encoding>
>>
>> AFAIK this could also appear as two headers:
>>
>>    Content-Encoding: gzip
>>    Content-Encoding: compress
>>
>> in RDF/XML:
>>
>>    <http:content-encoding>gzip</http:content-encoding>
>>    <http:content-encoding>compress</http:content-encoding>
> 
> This is wrong. It should be
> 
>     <http:content-encoding>tar, gzip</http:content-encoding>
> 
> since it describes a single encoding (which happens to be the result of 
> applying multiple transformations).

This was only an example. See section the last paragraph of 4.2 of HTTP 
1.1 (<http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2>):

    Multiple message-header fields with the same field-name MAY be
    present in a message if and only if the entire field-value for that
    header field is defined as a comma-separated list [i.e., #(values)].
    It MUST be possible to combine the multiple header fields into one
    "field-name: field-value" pair, without changing the semantics of the
    message, by appending each subsequent field-value to the first, each
    separated by a comma. The order in which header fields with the same
    field-name are received is therefore significant to the
    interpretation of the combined field value, and thus a proxy MUST NOT
    change the order of these field values when a message is forwarded.
-- 
Johannes Koch - Competence Center BIKA
Fraunhofer Institute for Applied Information Technology (FIT.LIFE)
Schloss Birlinghoven, D-53757 Sankt Augustin, Germany
Phone: +49-2241-142628    Fax: +49-2241-142065
Received on Tuesday, 17 October 2006 07:42:50 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 8 January 2008 14:18:27 GMT