Load a remote context via an unsupported network protocol #1650
Description
Under RDFLIb 6.0.1, I am trying the following example:
import json
from rdflib import Graph
def test_rdflib_jsonld():
graph = Graph()
graph.parse(
data=json.dumps({
'@context': {
'@import': 'ipfs://foo/bar/baz.json',
},
}),
format='json-ld',
)which obviously fails:
tests/test_experiments/test_rdflib_jsonld.py:5 (test_rdflib_jsonld)
test_rdflib_jsonld.py:8: in test_rdflib_jsonld
graph.parse(
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/graph.py:1258: in parse
parser.parse(source, self, **args) # type: ignore[call-arg]
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/plugins/parsers/jsonld.py:125: in parse
to_rdf(data, conj_sink, base, context_data, version, generalized_rdf)
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/plugins/parsers/jsonld.py:144: in to_rdf
return parser.parse(data, context, dataset)
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/plugins/parsers/jsonld.py:164: in parse
context.load(local_context, context.base)
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/plugins/shared/jsonld/context.py:362: in load
self._read_source(source, source_url, referenced_contexts)
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/plugins/shared/jsonld/context.py:426: in _read_source
imported = self._fetch_context(
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/plugins/shared/jsonld/context.py:413: in _fetch_context
source = source_to_json(source_url)
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/plugins/shared/jsonld/util.py:34: in source_to_json
source = create_input_source(source, format="json-ld")
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/parser.py:325: in create_input_source
) = _create_input_source_from_location(
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/parser.py:374: in _create_input_source_from_location
input_source = URLInputSource(absolute_location, format)
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/parser.py:218: in __init__
file = _urlopen(req)
../../../../.pyenv/versions/octadocs/lib/python3.8/site-packages/rdflib/parser.py:206: in _urlopen
return urlopen(req)
../../../../.pyenv/versions/3.8.1/lib/python3.8/urllib/request.py:222: in urlopen
return opener.open(url, data, timeout)
../../../../.pyenv/versions/3.8.1/lib/python3.8/urllib/request.py:525: in open
response = self._open(req, data)
../../../../.pyenv/versions/3.8.1/lib/python3.8/urllib/request.py:547: in _open
return self._call_chain(self.handle_open, 'unknown',
../../../../.pyenv/versions/3.8.1/lib/python3.8/urllib/request.py:502: in _call_chain
result = func(*args)
../../../../.pyenv/versions/3.8.1/lib/python3.8/urllib/request.py:1390: in unknown_open
raise URLError('unknown url type: %s' % type)
E urllib.error.URLError: <urlopen error unknown url type: ipfs>
My particular question is not specifically about adding IPFS support to RDFLib but in the venue of the latter's extensibility without modifying its core code base.
Question. Would it be possible to add support for new network protocols or new mechanisms of retrieval for JSON-LD contexts to RDFLib without modifying its source code? Is there a mechanism like loaders (https://github.com/digitalbazaar/pyld/blob/master/lib/pyld/documentloader/requests.py) in pyld? Or, perhaps, pyld loaders can be somehow reused when parsing JSON-LD documents with rdflib?
P. S. As a workaround, one could expand() the source JSON-LD document supplying an appropriate custom loader and then use the result as input for RDFLib but I'd be interested to see if there is a better solution.