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Re: .well-known

From: Ivan Herman <ivan@w3.org>
Date: Fri, 19 Jun 2015 07:19:51 +0200
Cc: Gregg Kellogg <gregg@greggkellogg.net>, W3C CSV on the Web Working Group <public-csv-wg@w3.org>
Message-Id: <D3E7C9DF-AA7F-4819-9FB1-AFBB8ED88F6F@w3.org>
To: David Booth <david@dbooth.org>
David,

I see one issue with your argumentation. You say:

[[[
- A *required* extra web access, nearly *every* time a conforming CSVW
processor is given a tabular data URL and wishes to find the associated
metadata -- because surely http://example/.well-known/csvm will be 404
(and not cachable) in the vast majority of cases.
]]]

which is of course correct in the sense that .well-known is not widely deployed. But, I think, everybody in the discussion agreed that the ideal solution that we should propose is to use the Link header of the CSV file's HTTP return to refer to the metadata file and, in the scheme we have, if the HTTP returns that header, then the CSVW processor will *not* look into .well-known. Ie, in some sense, we push people to use the best solutionÖ

B.t.w: why do you say 'not cachable'? Is that I restriction on .well-known? I have not seen anyÖ

Ivan





> On 18 Jun 2015, at 21:29 , David Booth <david@dbooth.org> wrote:
> 
> On 06/18/2015 12:56 PM, Gregg Kellogg wrote:
>>> On Jun 17, 2015, at 7:43 PM, David Booth <david@dbooth.org> wrote:
>>> 
>>> On 06/17/2015 02:29 AM, Ivan Herman wrote:
>>>> David,
>>>> 
>>>> the .well-known mechanism is the result of a long discussion with
>>>> the TAG that had difficulties with the principle of baking in
>>>> URI-schemes like "-metadata.json".
>>> 
>>> Is there a pointer to that discussion?   It sounds like the TAG
>>> concern is URI squatting.  URI squatting is an important concern,
>>> but I don't think it applies in this case, because -- if I've
>>> understood correctly -- a metadata file *explicitly* references the
>>> relevant data file, which in effect means that the URI owner has
>>> clearly indicated an intent to use that URI for that purpose.
>> 
>> Hi David, I found a link to the minutes here:
>> https://github.com/w3ctag/meetings/blob/gh-pages/2015/telcons/06-03-csv-minutes.md
>> (already added to the issue).
>> 
>> The minutes arenít particularly illuminating, but the issue raised by
>> mnot was definitely concern over squatting. At this point, it seems
>> to be settled. Iíve implemented it in my implementation, and it was
>> quite straight-forward, although it requires an extra GET, the result
>> of this can be cached for some time (subject to policies, of
>> course).
> 
> Thanks very much for the pointer.  I've read through the discussion and the TAG meeting minutes, and re-read RFC7320 , and I'm convinced that concerns about URI squatting are unfounded in this case.  I have written to the TAG to push back, explaining how this case is different from URI squatting, and the use of .well-known would actually cause more harm than good in this case:
> https://lists.w3.org/Archives/Public/www-tag/2015Jun/0011.html
> 
> BTW, you are extremely unlikely to be able to cache the result of accessing .well-known/csvw , because in the vast majority of cases it will be 404.
> 
> Thanks,
> David Booth
> 
>> 
>>> HOWEVER, I no longer see any mention of .well-known in the current
>>> editor's draft, so maybe my concern is moot:
>>> http://w3c.github.io/csvw/syntax/#locating-metadata
>> 
>> Itís still in a PR that hasnít yet been pulled:
>> https://github.com/w3c/csvw/pull/605. You likely say a page based on
>> that branch, rather than the gh-pages branch where the ED is
>> available.
>> 
>> Itís awaiting resolution of some minor wording on what ďno such file
>> is locatedĒ means, precisely.
>> 
>> Gregg
>> 
>>> Has the .well-known mechanism now been removed from the algorithm
>>> for finding metadata?
>>> 
>>> Thanks, David Booth
>>> 
>>>> Note that the agreement is to have a default fall-back, ie, if
>>>> the .well-known file does not exist then the client can fall back
>>>> to a default value which, actually, reproduces the previous
>>>> patterns. I think we should go ahead with this approach to cover
>>>> all points of views.
>>>> 
>>>> Ivan
>>>> 
>>>> 
>>>> 
>>>>> On 17 Jun 2015, at 05:20 , David Booth <david@dbooth.org>
>>>>> wrote:
>>>>> 
>>>>> I'm sorry to ask this question at this point, but is
>>>>> .well-known *really* needed for this?
>>>>> 
>>>>> I am concerned that it is just adding complexity and network
>>>>> accesses for dubious benefit.  AFAICT -- but please correct me
>>>>> if I've overlooked something -- the only "benefit" that
>>>>> .well-known adds here is to allow users to use non-standard
>>>>> names for their metadata files.  And what *real* benefit is
>>>>> that?  It seems to me to be adding pointless variability.  Are
>>>>> there really cases where users *cannot* name their metadata
>>>>> files to end with "-metadata.json"?  If so what are they?
>>>>> 
>>>>> David Booth
>>>>> 
>>>>> On 06/16/2015 09:20 PM, Yakov Shafranovich wrote:
>>>>>> Hmm. I am wondering if we can use the host-meta file
>>>>>> instead, skipping the registration, as per this:
>>>>>> 
>>>>>> https://tools.ietf.org/html/rfc6415#section-4.2
>>>>>> 
>>>>>> On Tue, Jun 16, 2015 at 4:01 PM, Gregg Kellogg
>>>>>> <gregg@greggkellogg.net> wrote:
>>>>>>> On Jun 16, 2015, at 12:55 PM, Yakov Shafranovich
>>>>>>> <yakov-ietf@shaftek.org> wrote:
>>>>>>> 
>>>>>>> What's the proposed format?
>>>>>>> 
>>>>>>> It's simply a file with one URI pattern per line. You can
>>>>>>> see the proposed text here:
>>>>>>> https://rawgit.com/w3c/csvw/98e728bcfef8d30e68c10f9cd798da0d39c7d172/syntax/index.html#site-wide-location-configuration
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>> 
>>>>>>> 
> Gregg
>>>>>>> 
>>>>>>> 
>>>>>>> On Jun 16, 2015 3:38 PM, "Ivan Herman" <ivan@w3.org>
>>>>>>> wrote:
>>>>>>>> 
>>>>>>>> Jeni, Gregg,
>>>>>>>> 
>>>>>>>> I have just received the green light from our system
>>>>>>>> people to set up the .well-known csw file. Can you ping
>>>>>>>> me when the changes are added to the documents and the
>>>>>>>> issue is closed? I would also need to know if it should
>>>>>>>> contain anything else than the default.
>>>>>>>> 
>>>>>>>> I will also take care of the registration when the
>>>>>>>> document is available.
>>>>>>>> 
>>>>>>>> Thanks
>>>>>>>> 
>>>>>>>> Ivan
>>>>>>>> 
>>>>>>>> ---- Ivan Herman +31 641044153
>>>>>>>> 
>>>>>>>> (Written on my mobile. Excuses for brevity and frequent
>>>>>>>> misspellings...)
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> ---- Ivan Herman, W3C Digital Publishing Activity Lead Home:
>>>> http://www.w3.org/People/Ivan/ mobile: +31-641044153 ORCID ID:
>>>> http://orcid.org/0000-0003-0782-2704


----
Ivan Herman, W3C
Digital Publishing Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
ORCID ID: http://orcid.org/0000-0003-0782-2704





Received on Friday, 19 June 2015 05:19:59 UTC

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