Re: ACTION-767: Confirm the EXACT wording of the proposed change to the user agent header on list

I'd like to draw this to a conclusion to I can produce a new draft today ...

I think we need to decide whether we mean send a User Agent header which 
starts exactly as follows (and may be extended in accordance with in 
accordance with [HTTP] [Section 14.43, User Agent Header]) " or whether, 
more in the spirit of HTTP, we say that when parsed in accordance with 
the BNF defining the User-Agent Header, the value is a <product> set to 
the value described followed by a <comment> set to the value described, 
followed by anything that conforms to the structure of the User-Agent 
header.

Note that we also have

#

Include an Accept header indicating that Internet media types understood 
by the default delivery context are accepted by sending exactly this header:

Accept: 
application/xhtml+xml,text/html;q=0.1,application/vnd.wap.xhtml+xml;q=0.1,text/css,image/jpeg,image/gif

#

Include an Accept-Charset header indicating that only UTF-8 is accepted 
by sending exactly this header:

Accept-Charset: UTF-8

#


so whatever we decide perhaps we should be consistent. In the case of 
Accept and Accept-Charset - these are very definitely not extensible, 
though perhaps we should allow for trivial syntax variations. I don't 
feel strongly about it.

I think it is clear that we _don't_ mean:

User-Agent: W3C-mobileOK/DDC-1.0 (see
http://www.w3.org/2006/07/mobileok-ddc (I am a malicious crawler))

We _do_ mean

User-Agent: W3C-mobileOK/DDC-1.0 (see
http://www.w3.org/2006/07/mobileok-ddc) (I am a malicious crawler)

Jo

Not wishing to bore with the detail but we did say EXACT:

(To my mind is is a little bit unclear exactly where LWS is allowed, it 
would appear to my untutored reading that any token, separator or quoted 
string forming part of a field value may be preceded by (or actually 
followed by) LWS.)

message-header = field-name ":" [ field-value ]
field-name = token
field-value = *( field-content | LWS )
field-content = <the OCTETs making up the field-value
  and consisting of either *TEXT or combinations
  of token, separators, and quoted-string>

User-Agent = "User-Agent" ":" 1*( product | comment )
product = token ["/" product-version]
product-version = token
token = 1*<any CHAR except CTLs or separators>
separators = "(" | ")" | "<" | ">" | "@" | "," | ";" | ":" | "\" | <"> | 
"/" | "[" | "]" | "?" | "=" | "{" | "}" | SP | HT
comment = "(" *( ctext | quoted-pair | comment ) ")"
ctext = <any TEXT excluding "(" and ")">
quoted-pair = "\" CHAR
LWS = [CRLF] 1*( SP | HT )
CRLF = CR LF
CR = <US-ASCII CR, carriage return (13)>
LF = <US-ASCII LF, linefeed (10)>
SP = <US-ASCII SP, space (32)>
HT = <US-ASCII HT, horizontal-tab (9)>

TEXT = <any OCTET except CTLs, but including LWS>
OCTET = <any 8-bit sequence of data>
CHAR = <any US-ASCII character (octets 0 - 127)>
CTL = <any US-ASCII control character (octets 0 - 31) and DEL (127)>


On 05/06/2008 21:09, Francois Daoust wrote:
> Jo Rabin wrote:
>> My understanding of the discussion was that we started from that and 
>> then went on to what is discussed below - which I believe is what is 
>> said in the resolution. I prefer what we have now, as it seems, do you.
> 
> Well, I prefer as well.
> 
> 
>>
>> I think it better not to specify the "string" it starts with because 
>> that in fact implies something about the spaces and other 
>> theoretically insignificant things to my mind.
> 
> OK, it's just that I still don't see why we can't impose the beginning 
> of the string.
> 
> Knowing that:
> User-Agent: W3C-mobileOK/DDC-1.0     (see 
> http://www.w3.org/2006/07/mobileok-ddc)
> (5 spaces between the product token and the comment)
> ... may be a valid User-Agent string (it may not, I haven't checked) 
> should not prevent us from saying that, for us, it must be:
> User-Agent: W3C-mobileOK/DDC-1.0 (see 
> http://www.w3.org/2006/07/mobileok-ddc)
> ... and then implementers may add whatever they want to the end of the 
> string.
> 
> That being said, since the first product token is perfectly defined as 
> "W3C-mobileOK/DDC-1.0", the proposed text is totally fine!
> 
> Francois.
> 
>>
>> Jo
>>
>> On 05/06/2008 17:11, Francois Daoust wrote:
>>> Jo Rabin wrote:
>>> [...]
>>>> Proposed Text:
>>>>
>>>> Include a User-Agent header indicating the Default Delivery Context 
>>>> by sending a product token set to "W3C-mobileOK/DDC-1.0" followed by 
>>>> a comment set to "(see http://www.w3.org/2006/07/mobileok-ddc)". 
>>>> These may be followed by any number of other product tokens or 
>>>> comments in accordance with [HTTP] [Section 14.43, User Agent 
>>>> Header]. The minimal User Agent header is:
>>>>
>>>> User-Agent: W3C-mobileOK/DDC-1.0 (see 
>>>> http://www.w3.org/2006/07/mobileok-ddc)
>>>
>>> OK, I don't mean to be picky on this, but I probably lost myself in 
>>> the BNG dicussion. My point is that I thought we agreed that the 
>>> following was valid:
>>>
>>> User-Agent: W3C-mobileOK/DDC-1.0 (see 
>>> http://www.w3.org/2006/07/mobileok-ddc; my comment)
>>>
>>> -> Based on the proposed text, it's not. Actually, I don't mind 
>>> either way, with a slight preference for it to be invalid anyway, but 
>>> I just want to make sure this is what was discussed and agreed.
>>>
>>> It's good if it's invalid, although I don't quite see in that case 
>>> why we don't simply state:
>>> "Include a User-Agent header indicating the Default Delivery Context 
>>> by sending a header that starts with:
>>> User-Agent: W3C-mobileOK/DDC-1.0 (see 
>>> http://www.w3.org/2006/07/mobileok-ddc)"
>>> But that's probably not rec-friendly enough...
>>
>

Received on Friday, 6 June 2008 09:07:16 UTC