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Re: Review of SPARQL 1.1 Uniform HTTP Protocol for Managing RDF Graphs review, rev1.56

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Wed, 06 Oct 2010 11:25:05 +0100
Message-ID: <4CAC4E81.3080100@epimorphics.com>
To: Steve Harris <steve.harris@garlik.com>
CC: "public-rdf-dawg@w3.org Group" <public-rdf-dawg@w3.org>


On 05/10/10 21:27, Steve Harris wrote:
> I've just read through the document. There's nothing catastrophically wrong, but there are some things that should be looked at. It could be draft published as-is, but I'd like to understand the Major issues first.
>
> Major
>
> 4.3
>
> I'm concerned that "Implementations of this protocol MUST obey the rules specified there regarding the resolution of relative URI references" rules out reverse proxies as implementations of this protocol. In our experience reverse proxies are commonly used infront of SPARQL endpoints to provide load balancing, additional security, and/or hardening. From the clients p.o.v. the proxy is the SPARQL endpoint.

The use of xml:base [1] applies to the XML element it is an attribute 
of.  In XML, and Turtle, the base URI can change during parsing.

-------------
PUT /rdf-graphs/service/?graph=1  HTTP/1.1
Host: example.com

<?xml version='1.0' encoding='UTF-8'?>
   <rdf:RDF
      xml:base='http://example2.com/rdf-graphs/employees/'
      xmlns:rdf='...'>
      ...
</rdf:RDF>
-------------

Here, it starts as http://example.com/rdf-graphs/service/?graph=1, and 
that is in-scope for determining ?graph=1. The base for the parsing of 
the XML document (the external base): 
http://example.com/rdf-graphs/service/?graph=1

It changes inside rdf:RDF element to 
http://example2.com/rdf-graphs/employees/

I thing the graph to PUT to is http://example.com/rdf-graphs/service/1

The example needs a blank line as well.


[1] http://www.w3.org/TR/xmlbase/#granularity

	Andy
Received on Wednesday, 6 October 2010 10:25:42 GMT

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