"""Utilities for loading JSON-LD contexts."""
import json
from functools import lru_cache
from typing import Mapping, Union
import curies
import importlib_resources
from curies import Converter
from rdflib.namespace import is_ncname
from .constants import EXTENDED_PREFIX_MAP
__all__ = [
"SSSOM_BUILT_IN_PREFIXES",
"get_converter",
"ConverterHint",
"ensure_converter",
]
SSSOM_BUILT_IN_PREFIXES = ("sssom", "owl", "rdf", "rdfs", "skos", "semapv")
SSSOM_CONTEXT = importlib_resources.files("sssom_schema").joinpath(
"context/sssom_schema.context.jsonld"
)
[docs]@lru_cache(1)
def get_converter() -> Converter:
"""Get a converter."""
return curies.chain([_get_built_in_prefix_map(), _get_default_converter()])
@lru_cache(1)
def _get_default_converter() -> Converter:
converter = Converter.from_extended_prefix_map(EXTENDED_PREFIX_MAP)
records = []
for record in converter.records:
if not is_ncname(record.prefix):
continue
record.prefix_synonyms = [s for s in record.prefix_synonyms if is_ncname(s)]
records.append(record)
return Converter(records)
def _load_sssom_context():
with open(SSSOM_CONTEXT) as file:
return json.load(file, strict=False)
@lru_cache(1)
def _get_built_in_prefix_map() -> Converter:
"""Get URI prefixes for built-in prefixes."""
context = _load_sssom_context()
prefix_map = {
prefix: uri_prefix
for prefix, uri_prefix in context["@context"].items()
if prefix in SSSOM_BUILT_IN_PREFIXES and isinstance(uri_prefix, str)
}
return Converter.from_prefix_map(prefix_map)
#: A type hint that specifies a place where one of three options can be given:
#: 1. a legacy prefix mapping dictionary can be given, which will get upgraded
#: into a :class:`curies.Converter`,
#: 2. a converter can be given, which might get modified. In SSSOM-py, this typically
#: means chaining behind the "default" prefix map
#: 3. None, which means a default converter is loaded
ConverterHint = Union[None, Mapping[str, str], Converter]
[docs]def ensure_converter(prefix_map: ConverterHint = None, *, use_defaults: bool = True) -> Converter:
"""Ensure a converter is available.
:param prefix_map: One of the following:
1. An empty dictionary or ``None``. This results in using the default
extended prefix map (currently based on a variant of the Bioregistry)
if ``use_defaults`` is set to true, otherwise just the builtin prefix
map including the prefixes in :data:`SSSOM_BUILT_IN_PREFIXES`
2. A non-empty dictionary representing a prefix map. This is loaded as a
converter with :meth:`Converter.from_prefix_map`. It is chained
behind the builtin prefix map to ensure none of the
:data:`SSSOM_BUILT_IN_PREFIXES` are overwritten with non-default values
3. A pre-instantiated :class:`curies.Converter`. Similarly to a prefix
map passed into this function, this is chained behind the builtin prefix
map
:param use_defaults: If an empty dictionary or None is passed to this function,
this parameter chooses if the extended prefix map (currently based on a
variant of the Bioregistry) gets loaded.
:returns: A re-usable converter
"""
if not prefix_map:
if use_defaults:
return get_converter()
else:
return _get_built_in_prefix_map()
if not isinstance(prefix_map, Converter):
prefix_map = Converter.from_prefix_map(prefix_map)
return curies.chain([_get_built_in_prefix_map(), prefix_map])