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application/csvm+json magic number [was Re: .well-known]

From: David Booth <david@dbooth.org>
Date: Fri, 19 Jun 2015 18:44:34 -0400
Message-ID: <55849B52.3030103@dbooth.org>
To: Gregg Kellogg <gregg@greggkellogg.net>
CC: public-csv-wg@w3.org

On 06/19/2015 04:19 PM, Gregg Kellogg wrote:
>> On Jun 19, 2015, at 12:17 PM, David Booth <david@dbooth.org>
>> wrote:
>> A technical question: does a CSVW metadata file supposed to contain
>> a particular string -- a 'magic number' perhaps -- that identifies
>> it as being a CSVW file?   If the metadata file is discovered first
>> -- such as through a web search -- then this would help prevent a
>> non-CSVW JSON file that just happens to look like a CSVW metadata
>> file from being erroneously interpreted as a CSVW metadata file.
> The IANA registration shows no Magic Number, but valid metadata
> documents MUST have the context "http://www.w3.org/ns/csvw, which
> will typically (although not necessarily) appear at the beginning of
> the document. In fact, this is what my JSON-LD processor looks to to
> not treat it as JSON-LD, but as Tabular Metadata.

I think this is important to note in the IANA registration.  I would 
suggest adding something like the following:
Magic number(s):
     An application/csvm+json document MUST contain a JSON property 
named "@context" whose value is either the string 
"http://www.w3.org/ns/csvw" or a JSON array whose first element is the 
string "http://www.w3.org/ns/csvw".  For parsers that are not 
JSON-aware, this means that an application/csvm+json document MUST 
contain the following two strings (including quotes), in order, 
separated by at least one character (not necessarily whitespace), 
somewhere in the document though usually near the beginning:


David Booth

> Gregg
>> I did not find the answer to this question when I looked in the
>> spec, but maybe I looked in the wrong place.
>> Thanks, David Booth
Received on Friday, 19 June 2015 22:45:08 UTC

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