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smushing

A FOAF smushing example.

Filter a graph by normalizing all foaf:Persons into URIs based on their mbox_sha1sum.

Suppose I get two FOAF documents each talking about the same person (according to mbox_sha1sum) but they each used a BNode for the subject. For this demo I’ve combined those two documents into one file:

This filters a graph by changing every subject with a foaf:mbox_sha1sum into a new subject whose URI is based on the sha1sum. This new graph might be easier to do some operations on.

An advantage of this approach over other methods for collapsing BNodes is that I can incrementally process new FOAF documents as they come in without having to access my ever-growing archive. Even if another 65b983bb397fb71849da910996741752ace8369b document comes in next year, I would still give it the same stable subject URI that merges with my existing data.

Attributes:

EXAMPLES_DIR module-attribute 

EXAMPLES_DIR = parent

STABLE module-attribute 

STABLE = Namespace('http://example.com/person/mbox_sha1sum/')

g module-attribute 

g = Graph()

newURI module-attribute 

newURI = {}

o module-attribute 

o = get(o, o)

out module-attribute 

out = Graph()

s module-attribute 

s = get(s, s)

ow_source: false show_docstring_attributes: false show_docstring_functions: false show_docstring_modules: false show_docstring_classes: false show_signature: false show_signature_annotations: false show_signature_type_parameters: false show_docstring_other_parameters: false show_docstring_parameters: false show_docstring_raises: false show_docstring_receives: false show_docstring_returns: false summary: false show_if_no_docstring: false

from pathlib import Path

from rdflib import Graph, Namespace
from rdflib.namespace import FOAF

STABLE = Namespace("http://example.com/person/mbox_sha1sum/")

EXAMPLES_DIR = Path(__file__).parent

if __name__ == "__main__":
    g = Graph()
    g.parse(f"{EXAMPLES_DIR / 'smushingdemo.n3'}", format="n3")

    newURI = {}  # old subject : stable uri  # noqa: N816
    for s, p, o in g.triples((None, FOAF["mbox_sha1sum"], None)):
        # For this graph, all objects are Identifiers, which is a subclass of
        # string. `n3` does allow for objects which are not Identifiers, like
        # subgraphs.
        assert isinstance(o, str)
        newURI[s] = STABLE[o]

    out = Graph()
    out.bind("foaf", FOAF)

    for s, p, o in g:
        s = newURI.get(s, s)
        o = newURI.get(o, o)  # might be linked to another person
        out.add((s, p, o))

    print(out.serialize())