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Re: Content-Disposition next steps

From: Adam Barth <ietf@adambarth.com>
Date: Sat, 4 Dec 2010 02:18:18 -0800
Message-ID: <AANLkTinfYnbq2gj8oFVcPwaTGgZaykLwxs_sQjTDHev+@mail.gmail.com>
To: Julian Reschke <julian.reschke@gmx.de>
Cc: Bjoern Hoehrmann <derhoermi@gmx.net>, Mark Nottingham <mnot@mnot.net>, HTTP Working Group <ietf-http-wg@w3.org>
On Fri, Dec 3, 2010 at 3:56 PM, Adam Barth <ietf@adambarth.com> wrote:
> On Thu, Dec 2, 2010 at 4:26 AM, Julian Reschke <julian.reschke@gmx.de> wrote:
>> I'm not totally sure what exactly to test; please elaborate.
>
> Content-Disposition: xfilename=foo.txt

Note: I've removed support for this syntax on the wiki.  It seemed
particularly goofy.

>>>> And as you lack higher
>>>> level control logic to actually separate parameters, this results in
>>>> `example="filename=example.txt"` having the filename `example.txt"`,
>>>> as opposed to the correct result, namely that there is no filename.
>>>
>>> Sounds like another good test case.
>>
>> <http://greenbytes.de/tech/tc2231/#dispextbadfn>
>>
>> failing in Chrome only.
>
> Oh good.  I'll update the wiki.  With a more elaborate grammar.

I've taken a stab at writing this requirement with a grammatical
presentation.  I'd appreciate some help with the grammar as it's not
my strong suit.  Here's what I've got (also on the wiki):

[[
unparsed-string = unbalanced-block / block * ( ";" block ) [ ";"
unbalanced-block ]
block = *run
unbalanced-block = *run unbalanced-run
run = unquoted-run / quoted-run
unquoted-run = non-quote *boring-octet
quoted-run = <"> *non-quote <">
unbalanced-run = <"> *non-quote
non-quote = <OCTET, except <"> >
boring-octet = <OCTET, except <"> and ";">
]]

I'm not overly confident in the first grammar.  What I'm trying to
encode is a parser with two states: initial and in-quote, together
with the following transition rules:

== State: initial ==
<"> => Buffer the current character, switch to the in-quote state, and
proceed to the next character.
";" => Emit the buffered characters, if any, and proceed to the next character.
EOF => Emit the buffered characters, if any, and terminate.
OTHER => Buffer the current character and proceed to the next character.

== State: in-quote ==
<"> => Buffer the current character, switch to the initial state, and
proceed to the next character.
EOF =>Emit the buffered characters, if any, and terminate.
OTHER => Buffer the current character and proceed to the next character.

My inclination is to write the state machine into the wiki, but I'm
hesitating because my understanding is that you all would prefer a
grammatical presentation.

Thanks,
Adam
Received on Saturday, 4 December 2010 10:19:20 GMT

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