namespace¶
Provides a simple representation of namespaces.
Namespace
¶
Represent a namespace.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
iri |
str |
IRI of namespace to represent. |
required |
label_annotations |
Sequence |
Sequence of label annotations. If given, check
the underlying ontology during attribute access if the name
correspond to a label. The label annotations should be ordered
from highest to lowest precedense.
If True is provided, |
() |
check |
bool |
Whether to check underlying ontology if the IRI exists during attribute access. If true, NoSuchIRIError will be raised if the IRI does not exist in this namespace. |
False |
reload |
Optional[bool] |
Whether to reload the ontology (which is needed when
|
None |
triplestore |
Optional[Union[Triplestore, str]] |
Use this triplestore for label lookup and checking.
Can be either a Triplestore object or an URL to load from.
Defaults to |
None |
format |
Optional[str] |
Format to use when loading from a triplestore. |
None |
cachemode |
int |
Deprecated. Use |
-1 |
triplestore_url |
Optional[str] |
Deprecated. Use the |
None |
Source code in tripper/namespace.py
class Namespace:
"""Represent a namespace.
Arguments:
iri: IRI of namespace to represent.
label_annotations: Sequence of label annotations. If given, check
the underlying ontology during attribute access if the name
correspond to a label. The label annotations should be ordered
from highest to lowest precedense.
If True is provided, `label_annotations` is set to
``(SKOS.prefLabel, RDF.label, SKOS.altLabel)``.
check: Whether to check underlying ontology if the IRI exists during
attribute access. If true, NoSuchIRIError will be raised if the
IRI does not exist in this namespace.
reload: Whether to reload the ontology (which is needed when
`label_annotations` or `check` are given) disregardless whether it
has been cached locally.
triplestore: Use this triplestore for label lookup and checking.
Can be either a Triplestore object or an URL to load from.
Defaults to `iri`.
format: Format to use when loading from a triplestore.
cachemode: Deprecated. Use `reload` instead (with `cachemode=NO_CACHE`
corresponding to `reload=True`).
triplestore_url: Deprecated. Use the `triplestore` argument instead.
"""
__slots__ = (
"_iri", # Ontology IRI
"_label_annotations", # Recognised annotations for labels
"_check", # Whether to check that IRIs exists
"_iris", # Dict mapping labels to IRIs
)
def __init__(
self,
iri: str,
label_annotations: "Sequence" = (),
check: bool = False,
reload: "Optional[bool]" = None,
triplestore: "Optional[Union[Triplestore, str]]" = None,
format: "Optional[str]" = None,
cachemode: int = -1,
triplestore_url: "Optional[str]" = None,
):
# pylint: disable=redefined-builtin
if cachemode != -1:
warnings.warn(
"The `cachemode` argument of Triplestore.__init__() is "
"deprecated. Use `reload` instead (with `cachemode=NO_CACHE` "
"corresponding to `reload=True`).\n\n"
"Will be removed in v0.3.",
DeprecationWarning,
stacklevel=2,
)
if reload is None and cachemode == 0:
reload = True
if triplestore_url:
warnings.warn(
"The `triplestore_url` argument of Triplestore.__init__() is "
"deprecated. Use the `triplestore` argument instead (which "
"now accepts a string argument with the URL).\n\n"
"Will be removed in v0.3.",
DeprecationWarning,
stacklevel=2,
)
if triplestore is None:
triplestore = triplestore_url
if label_annotations is True:
label_annotations = (SKOS.prefLabel, RDF.label, SKOS.altLabel)
need_triplestore = bool(check or label_annotations)
self._iri = str(iri)
self._label_annotations = (
tuple(label_annotations) if label_annotations else ()
)
self._check = bool(check)
self._iris: "Optional[dict]" = {} if need_triplestore else None
if need_triplestore:
self._update_iris(triplestore, reload=reload, format=format)
def _update_iris(self, triplestore=None, reload=False, format=None):
"""Update the internal cache from `triplestore`.
If `reload` is true, reload regardless we have a local cache.
"""
# pylint: disable=redefined-builtin
# Import Triplestore here to avoid cyclic import
from .triplestore import ( # pylint: disable=import-outside-toplevel,cyclic-import
Triplestore,
)
if not reload and self._load_cache():
return
if triplestore is None:
triplestore = self._iri
if isinstance(triplestore, (str, Path)):
# Ignore UnusedArgumentWarning when creating triplestore
with warnings.catch_warnings():
warnings.simplefilter("ignore", category=UnusedArgumentWarning)
ts = Triplestore("rdflib")
ts.parse(triplestore, format=format)
elif isinstance(triplestore, Triplestore):
ts = triplestore
elif not isinstance(triplestore, Triplestore):
raise NamespaceError(
"If given, `triplestore` argument must be either a URL "
"(string), Path or a Triplestore object."
)
# Add (label, full_iri) pairs
iri = self._iri.rstrip("/#")
for label in reversed(self._label_annotations):
self._iris.update(
(getattr(o, "value", o), s)
for s, o in ts.subject_objects(label)
if s.startswith(iri)
)
# Add (name, full_iri) pairs
self._iris.update(
(s[len(self._iri) :], s)
for s in ts.subjects()
if s.startswith(iri)
)
def _get_cachefile(self) -> Path:
"""Return path to cache file for this namespace."""
# pylint: disable=too-many-function-args
name = self._iri.rstrip("#/").rsplit("/", 1)[-1]
hashno = hashlib.shake_128(self._iri.encode()).hexdigest(5)
return get_cachedir() / f"{name}-{hashno}.cache"
def _save_cache(self):
"""Save current cache."""
# pylint: disable=invalid-name
try:
cachefile = self._get_cachefile()
if self._iris and not sys.is_finalizing():
with open(cachefile, "wb") as f:
pickle.dump(self._iris, f)
except OSError as exc:
warnings.warn(
f"Cannot access cache file: {exc}\n\n"
"You can select cache directory with the XDG_CACHE_HOME "
"environment variable."
)
def _load_cache(self) -> bool:
"""Update cache with cache file.
Returns true if there exists a cache file to load from.
"""
# pylint: disable=invalid-name
try:
cachefile = self._get_cachefile()
if self._iris is None:
self._iris = {}
if cachefile.exists():
with open(cachefile, "rb") as f:
self._iris.update(pickle.load(f)) # nosec
return True
return False
except OSError as exc:
warnings.warn(
f"Cannot create cache directory: {exc}\n\n"
"You can select cache directory with the XDG_CACHE_HOME "
"environment variable."
)
return False
def __getattr__(self, name):
if self._iris and name in self._iris:
return self._iris[name]
if self._check:
msg = ""
try:
cachefile = self._get_cachefile()
if cachefile.exists():
msg = (
"\nMaybe you have to remove the cache file: "
f"{cachefile}"
)
except OSError as exc:
warnings.warn(
f"Cannot access cache file: {exc}\n\n"
"You can select cache directory with the XDG_CACHE_HOME "
"environment variable."
)
raise NoSuchIRIError(self._iri + name + msg)
return self._iri + name
def __getitem__(self, key):
return self.__getattr__(key)
def __repr__(self):
return f"Namespace('{self._iri}')"
def __str__(self):
return self._iri
def __add__(self, other):
return self._iri + str(other)
def __hash__(self):
return hash(self._iri)
def __eq__(self, other):
return self._iri == str(other)
def __del__(self):
if self._iris:
self._save_cache()
get_cachedir(create=True)
¶
Returns cross-platform path to tripper cache directory.
If create is true, create the cache directory if it doesn't exists.
The XDG_CACHE_HOME environment variable is used if it exists.
Source code in tripper/namespace.py
def get_cachedir(create=True) -> Path:
"""Returns cross-platform path to tripper cache directory.
If `create` is true, create the cache directory if it doesn't exists.
The XDG_CACHE_HOME environment variable is used if it exists.
"""
site_cachedir = os.getenv("XDG_CACHE_HOME")
finaldir = None
if not site_cachedir:
if sys.platform.startswith("win32"):
site_cachedir = Path.home() / "AppData" / "Local"
finaldir = "Cache"
elif sys.platform.startswith("darwin"):
site_cachedir = Path.home() / "Library" / "Caches"
else: # Default to UNIX
site_cachedir = Path.home() / ".cache" # type: ignore
cachedir = Path(site_cachedir) / "tripper" # type: ignore
if finaldir:
cachedir /= finaldir
if create:
path = Path(cachedir.root)
for part in cachedir.parts[1:]:
path /= part
if not path.exists():
path.mkdir()
return cachedir