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Re: Delta Compression and UTF-8 Header Values

From: Martin Nilsson <nilsson@opera.com>
Date: Sat, 09 Feb 2013 15:12:24 +0100
To: ietf-http-wg@w3.org
Message-ID: <op.wr8p8u08iw9drz@uranium.westinmy-starwoodgp.com>
On Sat, 09 Feb 2013 00:53:10 +0100, Mark Nottingham <mnot@mnot.net> wrote:

> My .02 -
> RFC2616 implies that the range of characters available in headers is  
> ISO-8859-1 (while tilting the table heavily towards ASCII), and we've  
> clarified that in bis to recommend ASCII, while telling implementations  
> to handle anything else as opaque bytes.
> However, on the wire in HTTP/1, some bits are sent as UTF-8 (in  
> particular, the request-URI, from one or two browsers).

I don't see a reason to not UTF-8 encode all text fields. HTTP/1 forced a  
lot of heuristic code that tried to figure out how things where  
transformed on the way, and heuristics for decoders are bad. Though, as  
the world has moved to UTF-8, saying "opaque bytes" means UTF-8 in  
practice for everyone anyway. The problem are fields that ideally should  
be binary, say a hash for ETag. UTF-8 encoding would add 50% size there.

Creating a static huffman code for the ASCII part of Unicode shouldn't be  
a problem, as long as there is a prefix for non-ascii bytes.

/Martin Nilsson

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Received on Saturday, 9 February 2013 14:12:54 UTC

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