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Re: test-29: special characters in Turtle IRIs

From: Henry Story <henry.story@bblfish.net>
Date: Fri, 2 Mar 2012 17:50:49 +0100
Cc: public-rdf-comments@w3.org
Message-Id: <BF5EECB0-EFE6-46F5-9EA0-9713E5CBEA52@bblfish.net>
To: Alex Hall <alexhall@revelytix.com>

On 2 Mar 2012, at 15:23, Alex Hall wrote:

> On Fri, Mar 2, 2012 at 2:19 AM, Henry Story <henry.story@bblfish.net> wrote:
> pretty much the only positive test that fails for me at present consistently across Jena, Sesame and my
> implementation is Test-29.ttl [1] which contains the following statement
> 
> <http://example.org/node> <http://example.org/prop> <scheme:\u0001\u0002\u0003\u0004\u0005\u0006\u0007\u0008\t\n\u000B\u000C\r\u000E\u000F\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019\u001A\u001B\u001C\u001D\u001E\u001F !"#$%&'()*+,-./0123456789:/<=\u003E?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\u007F> .
> 
> This is causing the apache abdera IRI [2] library to barf . It looks like they put a lot of energy into this library, and so that's made me wonder where the error lies. This can be reproduced like this on the scala console
> 
> scala> import org.apache.abdera.i18n.iri._
> scala> val iriStr = "scheme:\u0001\u0002\u0003\u0004\u0005\u0006\u0007\u0008\t\n\u000B\u000C\r\u000E\u000F\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019"
> [line elided for control chars: possibly a scala signature]
> scala> val iriStr2 = "\u001A\u001B\u001C\u001D\u001E\u001F !\"#$%&'()*+,-./0123456789:/<=\u003E?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\u007F"
> [line elided for control chars: possibly a scala signature]
> scala> val iri = iriStr + iriStr2
> scala> val i = new IRI(iri)
> org.apache.abdera.i18n.iri.IRISyntaxException: org.apache.abdera.i18n.text.InvalidCharacterException: Invalid Character 0x1(?)
>        at org.apache.abdera.i18n.iri.IRI.parse(IRI.java:577)
>        at org.apache.abdera.i18n.iri.IRI.<init>(IRI.java:64)
>       ...
> 
> 
> I looked at http://tools.ietf.org/html/rfc3987 to see what the spec said there, but I don't think those characters are
> allowed. Can I remove this from the examples? What should I replace it with that would test the spec? Should we move this
> one to a bad-test?
> 
> This is another situation of syntactically valid Turtle that is not valid RDF. The IRI in question has Unicode-escaped control characters. All Unicode escape sequences are allowed in Turtle, but when the sequence is unescaped as part of the parsing process it becomes a syntactically invalid IRI (and therefore not valid for RDF). Any IRI parser will choke on this particular IRI.
> 
> I think it's a perfectly reasonable thing to do to incorporate an IRI parser into a Turtle parser, for validation as well as resolving relative IRIs against @base. For this reason, I think it's good practice to keep the positive parser tests in the realm of valid RDF, not just syntactically valid Turtle.

I fixed the examples for my test suite, by following the lead of Jena's fix on this

   https://github.com/betehess/pimp-my-rdf/commit/460d16ac3829dbd963e500c1367b5e45edf3428c

This was discussed there too 

    https://issues.apache.org/jira/browse/JENA-216

Henry


> 
> Regards,
> Alex
> 
>  
> 
>        Henry
> 
> 
> [1]  http://www.w3.org/TR/turtle/tests/test-29.ttl
> [2]  http://grepcode.com/file/repo1.maven.org/maven2/org.apache.abdera/abdera-i18n/1.1.2/org/apache/abdera/i18n/iri/IRI.java
>     http://abdera.apache.org/
> 
> 
> 
> Social Web Architect
> http://bblfish.net/
> 
> 
> 

Social Web Architect
http://bblfish.net/
Received on Friday, 2 March 2012 16:51:26 GMT

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