[apps-discuss] R: Re: Question about RFC 7239

"luigipinca@libero.it" <luigipinca@libero.it> Sun, 28 August 2016 21:22 UTC

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Date: Sun, 28 Aug 2016 23:22:02 +0200 (CEST)
From: "luigipinca@libero.it" <luigipinca@libero.it>
To: Julian Reschke <julian.reschke@gmx.de>, <apps-discuss@ietf.org>
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Subject: [apps-discuss] R: Re: Question about RFC 7239
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Thank you Julian but I still don't fully get it.
According to the #rule extension as shown in your link,

"foo , ,bar,"

is a valid value, so I assume that in our case

"; , ,"

is also a valid value as forwarded-element is defined like this

forwarded-element = [ forwarded-pair ] *( ";" [ forwarded-pair ] )

My main concern is actually on this definition. Why is forwarded-pair 
optional?

Regards,

Luigi

>----Messaggio originale----
>Da: "Julian Reschke" <julian.reschke@gmx.de>
>Data: 28/08/2016 22.27
>A: "luigipinca@libero.it"<luigipinca@libero.it>, <apps-discuss@ietf.org>
>Ogg: Re: [apps-discuss] Question about RFC 7239
>
>On 2016-08-28 21:50, luigipinca@libero.it wrote:
>> Hello,
>> I have a question about the "Forwarded" HTTP header field, defined in
>> section 4 of RFC 7239.
>> The ABNF definition for the header field value is:
>>
>> Forwarded   = 1#forwarded-element
>>
>> forwarded-element =
>>    [ forwarded-pair ] *( ";" [ forwarded-pair ] )
>>
>> forwarded-pair = token "=" value
>> value          = token / quoted-string
>>
>> token = <Defined in [RFC7230], Section 3.2.6>
>> quoted-string = <Defined in [RFC7230], Section 3.2.6>
>>
>> If I'm reading this correctly, an empty forwarded-element or one made of
>> only ";"  is a valid element.
>
>Nope.
>
>See <https://greenbytes.de/tech/webdav/rfc7230.html#abnf.extension>.
>
> > ...
>
>Best regards, Julian
>