Source code for rdflib.namespace
from rdflib.py3compat import format_doctest_out
__doc__ = format_doctest_out("""
===================
Namespace Utilities
===================
RDFLib provides mechanisms for managing Namespaces.
In particular, there is a :class:`~rdflib.namespace.Namespace` class
that takes as its argument the base URI of the namespace.
.. code-block:: pycon
>>> from rdflib.namespace import Namespace
>>> owl = Namespace('http://www.w3.org/2002/07/owl#')
Fully qualified URIs in the namespace can be constructed either by attribute
or by dictionary access on Namespace instances:
.. code-block:: pycon
>>> owl.seeAlso
rdflib.term.URIRef(%(u)s'http://www.w3.org/2002/07/owl#seeAlso')
>>> owl['seeAlso']
rdflib.term.URIRef(%(u)s'http://www.w3.org/2002/07/owl#seeAlso')
Automatic handling of unknown predicates
-----------------------------------------
As a programming convenience, a namespace binding is automatically
created when :class:`rdflib.term.URIRef` predicates are added to the graph.
Importable namespaces
-----------------------
The following namespaces are available by directly importing from rdflib:
* RDF
* RDFS
* OWL
* XSD
* FOAF
* SKOS
* DOAP
* DC
* DCTERMS
* VOID
.. code-block:: pycon
>>> from rdflib import OWL
>>> OWL.seeAlso
rdflib.term.URIRef(%(u)s'http://www.w3.org/2002/07/owl#seeAlso')
""")
import logging
_logger = logging.getLogger(__name__)
import os
from urlparse import urljoin, urldefrag
from urllib import pathname2url
from rdflib.term import URIRef, Variable, _XSD_PFX, _is_valid_uri
__all__ = [
'is_ncname', 'split_uri', 'Namespace',
'ClosedNamespace', 'NamespaceManager',
'XMLNS', 'RDF', 'RDFS', 'XSD', 'OWL',
'SKOS', 'DOAP', 'FOAF', 'DC', 'DCTERMS', 'VOID']
[docs]class Namespace(unicode):
__doc__ = format_doctest_out("""
Utility class for quickly generating URIRefs with a common prefix
>>> from rdflib import Namespace
>>> n = Namespace("http://example.org/")
>>> n.Person # as attribute
rdflib.term.URIRef(%(u)s'http://example.org/Person')
>>> n['first-name'] # as item - for things that are not valid python identifiers
rdflib.term.URIRef(%(u)s'http://example.org/first-name')
""")
[docs] def __new__(cls, value):
try:
rt = unicode.__new__(cls, value)
except UnicodeDecodeError:
rt = unicode.__new__(cls, value, 'utf-8')
return rt
@property
[docs] def term(self, name):
# need to handle slices explicitly because of __getitem__ override
return URIRef(self + (name if isinstance(name, basestring) else ''))
[docs] def __getattr__(self, name):
if name.startswith("__"): # ignore any special Python names!
raise AttributeError
else:
return self.term(name)
class URIPattern(unicode):
__doc__ = format_doctest_out("""
Utility class for creating URIs according to some pattern
This supports either new style formatting with .format
or old-style with %% operator
>>> u=URIPattern("http://example.org/%%s/%%d/resource")
>>> u%%('books', 12345)
rdflib.term.URIRef(%(u)s'http://example.org/books/12345/resource')
""")
def __new__(cls, value):
try:
rt = unicode.__new__(cls, value)
except UnicodeDecodeError:
rt = unicode.__new__(cls, value, 'utf-8')
return rt
def __mod__(self, *args, **kwargs):
return URIRef(unicode(self).__mod__(*args, **kwargs))
def format(self, *args, **kwargs):
return URIRef(unicode.format(self, *args, **kwargs))
def __repr__(self):
return "URIPattern(%r)"%unicode.__repr__(self)
[docs]class ClosedNamespace(object):
"""
A namespace with a closed list of members
Trying to create terms not listen is an error
"""
[docs] def __init__(self, uri, terms):
self.uri = uri
self.__uris = {}
for t in terms:
self.__uris[t] = URIRef(self.uri + t)
[docs] def term(self, name):
uri = self.__uris.get(name)
if uri is None:
raise Exception(
"term '%s' not in namespace '%s'" % (name, self.uri))
else:
return uri
[docs] def __getattr__(self, name):
if name.startswith("__"): # ignore any special Python names!
raise AttributeError
else:
return self.term(name)
class _RDFNamespace(ClosedNamespace):
"""
Closed namespace for RDF terms
"""
def __init__(self):
super(_RDFNamespace, self).__init__(
URIRef("http://www.w3.org/1999/02/22-rdf-syntax-ns#"),
terms=[
# Syntax Names
"RDF", "Description", "ID", "about", "parseType",
"resource", "li", "nodeID", "datatype",
# RDF Classes
"Seq", "Bag", "Alt", "Statement", "Property",
"List", "PlainLiteral",
# RDF Properties
"subject", "predicate", "object", "type",
"value", "first", "rest",
# and _n where n is a non-negative integer
# RDF Resources
"nil",
# Added in RDF 1.1
"XMLLiteral", "HTML", "langString"]
)
def term(self, name):
try:
i = int(name)
return URIRef("%s_%s" % (self.uri, i))
except ValueError:
return super(_RDFNamespace, self).term(name)
RDF = _RDFNamespace()
RDFS = ClosedNamespace(
uri=URIRef("http://www.w3.org/2000/01/rdf-schema#"),
terms=[
"Resource", "Class", "subClassOf", "subPropertyOf", "comment", "label",
"domain", "range", "seeAlso", "isDefinedBy", "Literal", "Container",
"ContainerMembershipProperty", "member", "Datatype"]
)
OWL = Namespace('http://www.w3.org/2002/07/owl#')
XSD = Namespace(_XSD_PFX)
SKOS = Namespace('http://www.w3.org/2004/02/skos/core#')
DOAP = Namespace('http://usefulinc.com/ns/doap#')
FOAF = Namespace('http://xmlns.com/foaf/0.1/')
DC = Namespace('http://purl.org/dc/elements/1.1/')
DCTERMS = Namespace('http://purl.org/dc/terms/')
VOID = Namespace('http://rdfs.org/ns/void#')
[docs]class NamespaceManager(object):
"""
Class for managing prefix => namespace mappings
Sample usage from FuXi ...
.. code-block:: python
ruleStore = N3RuleStore(additionalBuiltins=additionalBuiltins)
nsMgr = NamespaceManager(Graph(ruleStore))
ruleGraph = Graph(ruleStore,namespace_manager=nsMgr)
and ...
.. code-block:: pycon
>>> import rdflib
>>> from rdflib import Graph
>>> from rdflib.namespace import Namespace, NamespaceManager
>>> exNs = Namespace('http://example.com/')
>>> namespace_manager = NamespaceManager(Graph())
>>> namespace_manager.bind('ex', exNs, override=False)
>>> g = Graph()
>>> g.namespace_manager = namespace_manager
>>> all_ns = [n for n in g.namespace_manager.namespaces()]
>>> assert ('ex', rdflib.term.URIRef('http://example.com/')) in all_ns
>>>
"""
[docs] def __init__(self, graph):
self.graph = graph
self.__cache = {}
self.__log = None
self.bind("xml", u"http://www.w3.org/XML/1998/namespace")
self.bind("rdf", RDF)
self.bind("rdfs", RDFS)
self.bind("xsd", XSD)
def __get_store(self):
return self.graph.store
store = property(__get_store)
[docs] def qname(self, uri):
prefix, namespace, name = self.compute_qname(uri)
if prefix == "":
return name
else:
return ":".join((prefix, name))
[docs] def normalizeUri(self, rdfTerm):
"""
Takes an RDF Term and 'normalizes' it into a QName (using the
registered prefix) or (unlike compute_qname) the Notation 3
form for URIs: <...URI...>
"""
try:
namespace, name = split_uri(rdfTerm)
namespace = URIRef(unicode(namespace))
except:
if isinstance(rdfTerm, Variable):
return "?%s" % rdfTerm
else:
return "<%s>" % rdfTerm
prefix = self.store.prefix(namespace)
if prefix is None and isinstance(rdfTerm, Variable):
return "?%s" % rdfTerm
elif prefix is None:
return "<%s>" % rdfTerm
else:
qNameParts = self.compute_qname(rdfTerm)
return ':'.join([qNameParts[0], qNameParts[-1]])
[docs] def compute_qname(self, uri, generate=True):
if not _is_valid_uri(uri):
raise Exception('"%s" does not look like a valid URI, I cannot serialize this. Perhaps you wanted to urlencode it?'%uri)
if not uri in self.__cache:
namespace, name = split_uri(uri)
namespace = URIRef(namespace)
prefix = self.store.prefix(namespace)
if prefix is None:
if not generate:
raise Exception(
"No known prefix for %s and generate=False")
num = 1
while 1:
prefix = "ns%s" % num
if not self.store.namespace(prefix):
break
num += 1
self.bind(prefix, namespace)
self.__cache[uri] = (prefix, namespace, name)
return self.__cache[uri]
[docs] def bind(self, prefix, namespace, override=True):
namespace = URIRef(unicode(namespace))
# When documenting explain that override only applies in what cases
if prefix is None:
prefix = ''
bound_namespace = self.store.namespace(prefix)
if bound_namespace and bound_namespace != namespace:
# prefix already in use for different namespace
#
# append number to end of prefix until we find one
# that's not in use.
if not prefix:
prefix = "default"
num = 1
while 1:
new_prefix = "%s%s" % (prefix, num)
if not self.store.namespace(new_prefix):
break
num += 1
self.store.bind(new_prefix, namespace)
else:
bound_prefix = self.store.prefix(namespace)
if bound_prefix is None:
self.store.bind(prefix, namespace)
elif bound_prefix == prefix:
pass # already bound
else:
if override or bound_prefix.startswith("_"): # or a generated
# prefix
self.store.bind(prefix, namespace)
[docs] def namespaces(self):
for prefix, namespace in self.store.namespaces():
namespace = URIRef(namespace)
yield prefix, namespace
[docs] def absolutize(self, uri, defrag=1):
base = urljoin("file:", pathname2url(os.getcwd()))
result = urljoin("%s/" % base, uri, allow_fragments=not defrag)
if defrag:
result = urldefrag(result)[0]
if not defrag:
if uri and uri[-1] == "#" and result[-1] != "#":
result = "%s#" % result
return URIRef(result)
# From: http://www.w3.org/TR/REC-xml#NT-CombiningChar
#
# * Name start characters must have one of the categories Ll, Lu, Lo,
# Lt, Nl.
#
# * Name characters other than Name-start characters must have one of
# the categories Mc, Me, Mn, Lm, or Nd.
#
# * Characters in the compatibility area (i.e. with character code
# greater than #xF900 and less than #xFFFE) are not allowed in XML
# names.
#
# * Characters which have a font or compatibility decomposition
# (i.e. those with a "compatibility formatting tag" in field 5 of the
# database -- marked by field 5 beginning with a "<") are not allowed.
#
# * The following characters are treated as name-start characters rather
# than name characters, because the property file classifies them as
# Alphabetic: [#x02BB-#x02C1], #x0559, #x06E5, #x06E6.
#
# * Characters #x20DD-#x20E0 are excluded (in accordance with Unicode
# 2.0, section 5.14).
#
# * Character #x00B7 is classified as an extender, because the property
# list so identifies it.
#
# * Character #x0387 is added as a name character, because #x00B7 is its
# canonical equivalent.
#
# * Characters ':' and '_' are allowed as name-start characters.
#
# * Characters '-' and '.' are allowed as name characters.
from unicodedata import category
NAME_START_CATEGORIES = ["Ll", "Lu", "Lo", "Lt", "Nl"]
NAME_CATEGORIES = NAME_START_CATEGORIES + ["Mc", "Me", "Mn", "Lm", "Nd"]
ALLOWED_NAME_CHARS = [u"\u00B7", u"\u0387", u"-", u".", u"_"]
# http://www.w3.org/TR/REC-xml-names/#NT-NCName
# [4] NCName ::= (Letter | '_') (NCNameChar)* /* An XML Name, minus
# the ":" */
# [5] NCNameChar ::= Letter | Digit | '.' | '-' | '_' | CombiningChar
# | Extender
[docs]def is_ncname(name):
first = name[0]
if first == "_" or category(first) in NAME_START_CATEGORIES:
for i in xrange(1, len(name)):
c = name[i]
if not category(c) in NAME_CATEGORIES:
if c in ALLOWED_NAME_CHARS:
continue
return 0
# if in compatibility area
# if decomposition(c)!='':
# return 0
return 1
else:
return 0
XMLNS = "http://www.w3.org/XML/1998/namespace"
[docs]def split_uri(uri):
if uri.startswith(XMLNS):
return (XMLNS, uri.split(XMLNS)[1])
length = len(uri)
for i in xrange(0, length):
c = uri[-i - 1]
if not category(c) in NAME_CATEGORIES:
if c in ALLOWED_NAME_CHARS:
continue
for j in xrange(-1 - i, length):
if category(uri[j]) in NAME_START_CATEGORIES or uri[j] == "_":
ns = uri[:j]
if not ns:
break
ln = uri[j:]
return (ns, ln)
break
raise Exception("Can't split '%s'" % uri)
