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Implement bind_namespaces strategy for Prefix.cc #2239

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18 changes: 18 additions & 0 deletions examples/bind_prefix_cc.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
"""
Prefix.cc is a community curated prefix map. By using `bind_namespace="cc"`,
you can set a namespace manager or graph to dynamically load prefixes from
this resource.
"""

import rdflib

graph = rdflib.Graph(bind_namespaces="cc")

# The Gene Ontology is a biomedical ontology describing
# biological processes, cellular locations, and cellular components.
# It is typically abbreviated with the prefix "go" and uses PURLs
# issued by the Open Biological and Biomedical Ontologies Foundry.
prefix_map = {prefix: str(ns) for prefix, ns in graph.namespaces()}
assert "go" in prefix_map
assert prefix_map["go"] == "http://purl.obolibrary.org/obo/GO_"
assert graph.qname("http://purl.obolibrary.org/obo/GO_0032571") == "go:0032571"
19 changes: 15 additions & 4 deletions rdflib/namespace/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Optional, Set, Tuple, Union
from unicodedata import category
from urllib.parse import urldefrag, urljoin
from urllib.request import urlopen

from rdflib.term import URIRef, Variable, _is_valid_uri

Expand Down Expand Up @@ -418,11 +419,14 @@ def __init__(self, graph: "Graph", bind_namespaces: "_NamespaceSetString" = "cor
for prefix, ns in _NAMESPACE_PREFIXES_CORE.items():
self.bind(prefix, ns)
elif bind_namespaces == "cc":
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Why use the TLD name for prefix.cc? cc is also the conventional prefix for creativecommons, so this might be confusing.

(I would also prefer having this as a utility (e.g. graph.bind_namespaces(util.get_prefix_cc()) rather than a flag to Graph. That would be more explicit and lets the user control network access and caching.)

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@niklasl I am happy to do whatever the RDFLib team decides on, but this interface and nomenclature was already predefined, so I just filled it in with an implementation as suggested.

I agree that since prefix.cc relies on a network connection that this is a bit of a tricky situation.

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Actually, you can achieve the same effect using RDFLib as is, using just:

from rdflib import Graph

graph = Graph()
graph.parse('https://prefix.cc/context.jsonld')

for pfx, ns in graph.namespaces():
    print(pfx, ns)

This yields one very interesting difference though: the go prefix won't work, as it ends in a _, which is not treated as a namespace prefix in JSON-LD 1.1, since it does not en with a URI gen-delim (it has to be explicitly declared using "@prefix": true in the context to be treated as a prefix anyway).

for prefix, ns in _NAMESPACE_PREFIXES_RDFLIB.items():
self.bind(prefix, ns)
for prefix, ns in _NAMESPACE_PREFIXES_CORE.items():
self.bind(prefix, ns)
# bind any prefix that can be found with lookups to prefix.cc
# first bind core and rdflib ones
# work out remainder - namespaces without prefixes
# only look those ones up
raise NotImplementedError("Haven't got to this option yet")
for prefix, ns in _get_prefix_cc().items():
# note that prefixes are lowercase-only in prefix.cc
self.bind(prefix, ns)
elif bind_namespaces == "core":
# bind a few core RDF namespaces - default
for prefix, ns in _NAMESPACE_PREFIXES_CORE.items():
Expand Down Expand Up @@ -722,6 +726,13 @@ def absolutize(self, uri: str, defrag: int = 1) -> URIRef:
return URIRef(result)


def _get_prefix_cc():
"""Get the context from Prefix.cc."""
response = urlopen("https://prefix.cc/context.jsonld")
context = json.loads(response.read())
return context["@context"]
Comment on lines +734 to +738
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One concern here is that there are some valid "@context" values [ref] that will not be handled correctly here, it may be that they don't appear in prefix.cc, but it may be good to confirm that somehow.

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yes, it's the case that there are no special values in this context dictionary based on the way that the context is constructed (https://github.com/cygri/prefix.cc/blob/cbc85c00e59e00cf4fee697374109fdd9027231a/templates/format/jsonld.php) and the strict requirements on prefixes (though right now I am having a hard time finding where it's documented that these have to be lowercase strings of alphanumeric characters length <= 10)



# From: http://www.w3.org/TR/REC-xml#NT-CombiningChar
#
# * Name start characters must have one of the categories Ll, Lu, Lo,
Expand Down
16 changes: 16 additions & 0 deletions test/test_namespacemanager.py
Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,22 @@ def test_graph_bind_namespaces(
assert namespaces is None


def test_graph_bind_cc():
"""Test binding Prefix.cc.

Note that since prefix.cc is an inherently dynamic resource,
that checking an exact equivalence is not applicable.
"""
graph = Graph(bind_namespaces="cc")
namespaces = {*graph.namespaces()}
for namespaces in [
_NAMESPACE_PREFIXES_CORE,
_NAMESPACE_PREFIXES_RDFLIB,
{"go", "atcc"}, # represent some prefixes in Prefix.cc
]:
assert all(ns in namespaces for ns in _NAMESPACE_PREFIXES_CORE)


@pytest.mark.parametrize(
["selector", "expected_result"],
[
Expand Down