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

+1 (like in crazy in love) for the "starts exactly as follows (and may 
be extended in accordance with [HTTP] [Section 14.43, User Agent 
Header]", especially if we're to be consistent with the Accept and 
Accept-Charset headers and would have to change the wording to an 
in-the-spirit-of-HTTP one for these two headers as well.

Matching strings exactly and matching beginning of strings is easy. 
Having to apply BNF grammar parsing is less trivial. I can see that a 
mobileOK checker implementation might use some HTTP library to send 
requests that doesn't quite allow to control the headers to match these 
strings entirely. I don't think that's really going to ever happen in 
practice though.

Again, I'm not willing to block/postpone anything. It's a +1 to the text 
that follows the Occam's Razor principle IMO. But it's not a -1 to the 
alternative text. If no one else has any strong view one way or the 
other, I leave the final decision in the hands of the editor with pleasure.

Francois.


Jo Rabin wrote:
> 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 10:48:14 UTC