data.nq serialization issues

[Magnus Knuth]

We experienced some problems with reading the data (data.nq.gz) into our system.

In the early versions there are some problems primarily with invalid URIs, obviously originating from blank nodes:

  $ rapper -v

2.0.15
  $ curl http://swse.deri.org/dyldo/data/2012-05-06/data.nq.gz | gzip -dc | rapper -i nquads -c - http://swse.deri.org/dyldo/data/2012-05-06/data

...

rapper: Error - URI http://swse.deri.org/dyldo/data/2012-05-06/data:118710 column 113 - URI 'node16sht9e40x3284' is not absolute.

rapper: Error - URI http://swse.deri.org/dyldo/data/2012-05-06/data:118711 column 20 - URI 'node16sht9e40x3284' is not absolute.

rapper: Error - URI http://swse.deri.org/dyldo/data/2012-05-06/data:118712 column 20 - URI 'node16sht9e40x3284' is not absolute.

...

Respective snippet from the file:

<http://www-di.inf.puc-rio.br/schwabe/foaf-schwabe.rdf#me> <http://xmlns.com/foaf/0.1/knows> <node16sht9e40x3284> <http://www-di.inf.puc-rio.br/schwabe/foaf-schwabe.rdf> .
<node16sht9e40x3284> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person> <http://www-di.inf.puc-rio.br/schwabe/foaf-schwabe.rdf> .
<node16sht9e40x3284> <http://xmlns.com/foaf/0.1/mbox_sha1sum> "80248cbb1109104d97aae884138a6afcda688bd2" <http://www-di.inf.puc-rio.br/schwabe/foaf-schwabe.rdf> .

In the later versions this seems to be fixed, nevertheless, there are still issues with URIs

   $ curl http://swse.deri.org/dyldo/data/2015-11-29/data.nq.gz | gzip -dc | rapper -i nquads -c - http://swse.deri.org/dyldo/data/2015-11-29/data

...

rapper: Error - URI http://swse.deri.org/dyldo/data/2015-11-29/data:725169 column 158 - Saw '*', expected predict term <URIref>

...

rapper: Error - URI http://swse.deri.org/dyldo/data/2015-11-29/data:921477 column 146 - Saw '@', expected Graph term <URIref>, _:bnodeID

...

Respective snippet from the file:

_:httpx3Ax2Fx2Fbnbx2Edatax2Eblx2Eukx2Fdocx2Fresourcex2F006893251x2Erdfx3Fx5Fmetadatax3Dallx2Cviewsx2Cformatsx2Cex78ecutionx2Cbindingsx26x5Fviewx3Dallxxtermx5F* <http://purl.org/linked-data/api/vocab#label> "*" <http://bnb.data.bl.uk/doc/resource/006893251.rdf?_metadata=all,views,formats,execution,bindings&_view=all> .
...
<http://creativecommons.org/licenses/by-nc-nd/3.0/> <http://purl.org/dc/elements/1.1/title> "Autorstvo-Nekomercijalno-Bez prerada 3.0 Unported"@sr@latin <http://creativecommons.org/licenses/by-nc-nd/3.0/rdf> .

My question was, which serializer are you using for creating the NQuads. If it is self-implemented, please verify it is compliant with the standards.

[Usman Akhtar]

Hello, 

Although your question is very old, i had a similar problem with i have tried this https://rdflib.readthedocs.io/en/stable/ 

Thank you.