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Re: [hybi] Review of draft-ietf-hybi-thewebsocketprotocol-13

"Richard L. Barnes" <rbarnes@bbn.com> Tue, 06 September 2011 16:53 UTC

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From: "Richard L. Barnes" <rbarnes@bbn.com>
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Date: Tue, 06 Sep 2011 12:55:08 -0400
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To: Bjoern Hoehrmann <derhoermi@gmx.net>
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Subject: Re: [hybi] Review of draft-ietf-hybi-thewebsocketprotocol-13
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Well, ok.  No state related to UTF-8.  Any intermediary that deals with fragmentation will have to remember the opcode/extensions.

--Richard


On Sep 6, 2011, at 12:38 PM, Bjoern Hoehrmann wrote:

> * Richard L. Barnes wrote:
>> If frames are valid utf-8, then you don't need to keep any state (on
>> either end of the connection).
> 
> That's somewhat misleading. If you accept for instance both binary and
> text frames, you have to maintain the type of the first frame so you can
> reject continuation frames of the wrong type. You may also have to main-
> tain state coming from extension data or your protocol may require other
> state to be maintained. A minimal byte-oriented UTF-8 validator has nine
> states http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ and that seems less
> onerous to maintain than having fragmenting senders and forwarders to
> find where character and byte boundaries coincide (you need to have the
> encoded text available and re-sychronize to character boundaries, or
> have the character stream available with analyze the encoded widths, or
> you have to include padding within the text, to start sending).
> -- 
> Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de
> Am Badedeich 7 · Telefon: +49(0)160/4415681 · http://www.bjoernsworld.de
> 25899 Dagebüll · PGP Pub. KeyID: 0xA4357E78 · http://www.websitedev.de/

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