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Oort
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Oort is a a Python_-based toolkit for accessing RDF_ graphs as plain objects.
It uses RDFLib_ for the heavy lifting.
.. _RDF: http://www.rdfabout.net
.. _Python: http://python.org
.. _RDFLib: http://rdflib.net
Overview
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``oort.rdfview``
Contains classes and functions used for defining RDF queries and selectors,
i.e. declarations used to pick properties and associated sub-queries from a
chosen resource (similar to how many ORM-toolkits work).
``oort.util.queries``
Some basic base ``RdfQuery`` subtypes for common use (e.g. getting at
localized annotation properties such as ``rdfs:label`` and similar).
``oort.util.graphs``
A collection of basic "filesystem-to-graph" utilities.
How?
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By subclassing ``oort.rdfview.RdfQuery`` and adding attributes which are
instances of one of the Selector subclasses from that package, you define a set
of rdf properties which are to be retrieved about a given subject (from a given
graph, in a given language). The selectors are given a ``URIRef`` which
determines the property. Or a ``Namespace``, in which case the name of the
attribute will be used.
These are some of the predefined classes from ``oort.util.queries``::
class Typed(RdfQuery):
rdfType = one(RDF.type)
class Labelled(RdfQuery):
label = localized(RDFS)
class Annotated(Labelled):
comment = localized(RDFS)
class Resource(Annotated, Typed):
pass
Selectors can also be given ``RdfQuery`` types (or names of types, to enable
e.g. cyclic references) which are used to describe their selected resources
recursively. Use like this::
SIOC = Namespace("http://rdfs.org/sioc/ns#")
class Item(Annotated):
_rdfbase_ = SIOC # sets default namespace base for this RdfQuery
name = localized()
description = localized()
seeAlso = each(RDFS) >> Annotated
The overloaded ``>>`` is just sugar for::
seeAlso = each(RDFS).viewed_as(Annotated)
Predefined selectors in ``oort.rdfview`` are: ``one``, ``each``,
``one_where_self_is``, ``each_where_self_is``, ``collection``, ``localized``,
``i18n_dict``, ``each_localized`` and ``localized_xml``.
RdfQueries are either directly instantiated with an RDFLib ``Graph`` instance,
language (string) and ``URIRef`` instance, or used via ``QueryContext``, which
facilitates this and other things.
Se more examples (and test source code) at the `Oort Website`_.
.. _`Oort Website`: http://oort.to
The latest development version can be installed from the
`Oort SVN Trunk <http://oort.googlecode.com/svn/Oort/trunk#egg=Oort-dev>`_.
