[redland-dev] [Rasqal RDF Query Library 0000356]: Support stdin as data source for roqet

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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http://bugs.librdf.org/mantis/view.php?id=356 
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Reported By:                arto
Assigned To:                
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Project:                    Rasqal RDF Query Library
Issue ID:                   356
Category:                   utilities
Reproducibility:            always
Severity:                   feature
Priority:                   normal
Status:                     new
Query Language:             SPARQL 
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Date Submitted:             2010-03-04 18:49
Last Modified:              2010-03-04 18:49
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Summary:                    Support stdin as data source for roqet
Description: 
As discussed on #swig today [1], roqet doesn't currently support using the
standard input as a data source for executing SPARQL queries.

I first tried using "-" for the --data option, but that results in:

    $ cat drupal.nt | roqet -i sparql -e "SELECT * WHERE { ?s ?p ?o }" -D
-
    roqet: Running query 'SELECT * WHERE { ?s ?p ?o }'
    roqet: Error - URI file:///tmp/:1 - Failed to parse URI - - Resolving
URI failed: Couldn't resolve host '-'
    roqet: Error - URI file:///tmp/:1 - Failed to make triples source.
    roqet: Query execution failed

Next, I tried Dave's suggested trick of using "file:/dev/stdin", but that
results in:

    $ cat drupal.nt | roqet -i sparql -e "SELECT * WHERE { ?s ?p ?o }" -D
file:/dev/stdin
    roqet: Running query 'SELECT * WHERE { ?s ?p ?o }'
    roqet: Error - URI file:///tmp/:1 - Failed to parse URI
file:///dev/stdin - Failed to guess parser from content type '(none)'
    roqet: Error - URI file:///tmp/:1 - Failed to make triples source.
    roqet: Query execution failed

It would awesome if one or the other of these worked, but it could perhaps
require adding a new command-line option for specifying the data source
serialization format. Of course, falling back to N-Triples as the default
format would be a quick fix and would enable using roqet to build Unix
pipelines for RDF [2].

Now, this probably isn't a bug per se but simply me asking too much of
roqet, so I'm marking this as a feature request.

[1] http://chatlogs.planetrdf.com/swig/2010-03-04.html
[2] http://blog.datagraph.org/2010/03/grepping-ntriples

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Issue History 
Date Modified    Username       Field                    Change               
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2010-03-04 18:49 arto           New Issue                                    
2010-03-04 18:49 arto           Query Language            => SPARQL          
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