Source code for rdflib.term

"""
This module defines the different types of terms. Terms are the kinds of
objects that can appear in a quoted/asserted triple. This includes those
that are core to RDF:

* :class:`Blank Nodes <rdflib.term.BNode>`
* :class:`URI References <rdflib.term.URIRef>`
* :class:`Literals <rdflib.term.Literal>` (which consist of a literal value,datatype and language tag)

Those that extend the RDF model into N3:

* :class:`Formulae <rdflib.graph.QuotedGraph>`
* :class:`Universal Quantifications (Variables) <rdflib.term.Variable>`

And those that are primarily for matching against 'Nodes' in the
underlying Graph:

* REGEX Expressions
* Date Ranges
* Numerical Ranges

"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
# from __future__ import unicode_literals

__all__ = [
    'bind',

    'Node',
    'Identifier',

    'URIRef',
    'BNode',
    'Literal',

    'Variable',
    'Statement',
]

import logging
logger = logging.getLogger(__name__)
import warnings
import math

import base64
import xml.dom.minidom

from datetime import date, time, datetime, timedelta
from re import sub, compile
from collections import defaultdict

from isodate import parse_time, parse_date, parse_datetime, Duration, parse_duration, duration_isoformat

import rdflib
from six import PY2
from six import PY3
from six import b
from rdflib.compat import long_type
from six import string_types
from six import text_type
from six.moves.urllib.parse import urldefrag
from six.moves.urllib.parse import urljoin
from six.moves.urllib.parse import urlparse

skolem_genid = "/.well-known/genid/"
rdflib_skolem_genid = "/.well-known/genid/rdflib/"
skolems = {}


_invalid_uri_chars = '<>" {}|\\^`'


def _is_valid_uri(uri):
    for c in _invalid_uri_chars:
        if c in uri:
            return False
    return True


_lang_tag_regex = compile('^[a-zA-Z]+(?:-[a-zA-Z0-9]+)*$')


def _is_valid_langtag(tag):
    return bool(_lang_tag_regex.match(tag))


def _is_valid_unicode(value):
    """
    Verify that the provided value can be converted into a Python
    unicode object.
    """
    if isinstance(value, bytes):
        coding_func, param = getattr(value, 'decode'), 'utf-8'
    elif PY3:
        coding_func, param = str, value
    else:
        coding_func, param = unicode, value

    # try to convert value into unicode
    try:
        coding_func(param)
    except UnicodeError:
        return False
    return True


[docs]class Node(object): """ A Node in the Graph. """ __slots__ = ()
[docs]class Identifier(Node, text_type): # allow Identifiers to be Nodes in the Graph """ See http://www.w3.org/2002/07/rdf-identifer-terminology/ regarding choice of terminology. """ __slots__ = ()
[docs] def __new__(cls, value): return text_type.__new__(cls, value)
[docs] def eq(self, other): """A "semantic"/interpreted equality function, by default, same as __eq__""" return self.__eq__(other)
[docs] def neq(self, other): """A "semantic"/interpreted not equal function, by default, same as __ne__""" return self.__ne__(other)
[docs] def __ne__(self, other): return not self.__eq__(other)
[docs] def __eq__(self, other): """ Equality for Nodes. >>> BNode("foo")==None False >>> BNode("foo")==URIRef("foo") False >>> URIRef("foo")==BNode("foo") False >>> BNode("foo")!=URIRef("foo") True >>> URIRef("foo")!=BNode("foo") True >>> Variable('a')!=URIRef('a') True >>> Variable('a')!=Variable('a') False """ if type(self) == type(other): return text_type(self) == text_type(other) else: return False
[docs] def __gt__(self, other): """ This implements ordering for Nodes, This tries to implement this: http://www.w3.org/TR/sparql11-query/#modOrderBy Variables are not included in the SPARQL list, but they are greater than BNodes and smaller than everything else """ if other is None: return True # everything bigger than None elif type(self) == type(other): return text_type(self) > text_type(other) elif isinstance(other, Node): return _ORDERING[type(self)] > _ORDERING[type(other)] return NotImplemented
[docs] def __lt__(self, other): if other is None: return False # Nothing is less than None elif type(self) == type(other): return text_type(self) < text_type(other) elif isinstance(other, Node): return _ORDERING[type(self)] < _ORDERING[type(other)] return NotImplemented
[docs] def __le__(self, other): r = self.__lt__(other) if r: return True return self == other
[docs] def __ge__(self, other): r = self.__gt__(other) if r: return True return self == other
# use parent's hash for efficiency reasons # clashes of 'foo', URIRef('foo') and Literal('foo') are typically so rare # that they don't justify additional overhead. Notice that even in case of # clash __eq__ is still the fallback and very quick in those cases. __hash__ = text_type.__hash__
[docs]class URIRef(Identifier): """ RDF URI Reference: http://www.w3.org/TR/rdf-concepts/#section-Graph-URIref """ __slots__ = ()
[docs] def __new__(cls, value, base=None): if base is not None: ends_in_hash = value.endswith("#") value = urljoin(base, value, allow_fragments=1) if ends_in_hash: if not value.endswith("#"): value += "#" if not _is_valid_uri(value): logger.warning('%s does not look like a valid URI, trying to serialize this will break.'%value) try: rt = text_type.__new__(cls, value) except UnicodeDecodeError: rt = text_type.__new__(cls, value, 'utf-8') return rt
[docs] def toPython(self): return text_type(self)
[docs] def n3(self, namespace_manager=None): """ This will do a limited check for valid URIs, essentially just making sure that the string includes no illegal characters (``<, >, ", {, }, |, \\, `, ^``) :param namespace_manager: if not None, will be used to make up a prefixed name """ if not _is_valid_uri(self): raise Exception('"%s" does not look like a valid URI, I cannot serialize this as N3/Turtle. Perhaps you wanted to urlencode it?'%self) if namespace_manager: return namespace_manager.normalizeUri(self) else: return "<%s>" % self
[docs] def defrag(self): if "#" in self: url, frag = urldefrag(self) return URIRef(url) else: return self
[docs] def __reduce__(self): return (URIRef, (text_type(self),))
[docs] def __getnewargs__(self): return (text_type(self), )
if PY2:
[docs] def __str__(self): return self.encode()
[docs] def __repr__(self): if self.__class__ is URIRef: clsName = "rdflib.term.URIRef" else: clsName = self.__class__.__name__ return """%s(%s)""" % (clsName, super(URIRef, self).__repr__())
[docs] def __add__(self, other): return self.__class__(text_type(self) + other)
[docs] def __radd__(self, other): return self.__class__(other + text_type(self))
[docs] def __mod__(self, other): return self.__class__(text_type(self) % other)
[docs] def de_skolemize(self): """ Create a Blank Node from a skolem URI, in accordance with http://www.w3.org/TR/rdf11-concepts/#section-skolemization. This function accepts only rdflib type skolemization, to provide a round-tripping within the system. .. versionadded:: 4.0 """ if isinstance(self, RDFLibGenid): parsed_uri = urlparse("%s" % self) return BNode( value=parsed_uri.path[len(rdflib_skolem_genid):]) elif isinstance(self, Genid): bnode_id = "%s" % self if bnode_id in skolems: return skolems[bnode_id] else: retval = BNode() skolems[bnode_id] = retval return retval else: raise Exception("<%s> is not a skolem URI" % self)
class Genid(URIRef): __slots__ = () @staticmethod def _is_external_skolem(uri): if not isinstance(uri, string_types): uri = str(uri) parsed_uri = urlparse(uri) gen_id = parsed_uri.path.rfind(skolem_genid) if gen_id != 0: return False return True class RDFLibGenid(Genid): __slots__ = () @staticmethod def _is_rdflib_skolem(uri): if not isinstance(uri, string_types): uri = str(uri) parsed_uri = urlparse(uri) if parsed_uri.params != "" \ or parsed_uri.query != "" \ or parsed_uri.fragment != "": return False gen_id = parsed_uri.path.rfind(rdflib_skolem_genid) if gen_id != 0: return False return True def _unique_id(): # Used to read: """Create a (hopefully) unique prefix""" # now retained merely to leave interal API unchanged. # From BNode.__new__() below ... # # acceptable bnode value range for RDF/XML needs to be # something that can be serialzed as a nodeID for N3 # # BNode identifiers must be valid NCNames" _:[A-Za-z][A-Za-z0-9]* # http://www.w3.org/TR/2004/REC-rdf-testcases-20040210/#nodeID return "N" # ensure that id starts with a letter def _serial_number_generator(): """ Generates UUID4-based but ncname-compliant identifiers. """ from uuid import uuid4 def _generator(): return uuid4().hex return _generator
[docs]class BNode(Identifier): """ Blank Node: http://www.w3.org/TR/rdf-concepts/#section-blank-nodes """ __slots__ = ()
[docs] def __new__(cls, value=None, _sn_gen=_serial_number_generator(), _prefix=_unique_id()): """ # only store implementations should pass in a value """ if value is None: # so that BNode values do not collide with ones created with # a different instance of this module at some other time. node_id = _sn_gen() value = "%s%s" % (_prefix, node_id) else: # TODO: check that value falls within acceptable bnode value range # for RDF/XML needs to be something that can be serialzed # as a nodeID for N3 ?? Unless we require these # constraints be enforced elsewhere? pass # assert is_ncname(text_type(value)), "BNode identifiers # must be valid NCNames" _:[A-Za-z][A-Za-z0-9]* # http://www.w3.org/TR/2004/REC-rdf-testcases-20040210/#nodeID return Identifier.__new__(cls, value)
[docs] def toPython(self): return text_type(self)
[docs] def n3(self, namespace_manager=None): return "_:%s" % self
[docs] def __getnewargs__(self): return (text_type(self), )
[docs] def __reduce__(self): return (BNode, (text_type(self),))
if PY2:
[docs] def __str__(self): return self.encode()
[docs] def __repr__(self): if self.__class__ is BNode: clsName = "rdflib.term.BNode" else: clsName = self.__class__.__name__ return """%s('%s')""" % (clsName, str(self))
[docs] def skolemize(self, authority=None, basepath=None): """ Create a URIRef "skolem" representation of the BNode, in accordance with http://www.w3.org/TR/rdf11-concepts/#section-skolemization .. versionadded:: 4.0 """ if authority is None: authority = "http://rdlib.net/" if basepath is None: basepath = rdflib_skolem_genid skolem = "%s%s" % (basepath, text_type(self)) return URIRef(urljoin(authority, skolem))
[docs]class Literal(Identifier): __doc__ = """ RDF Literal: http://www.w3.org/TR/rdf-concepts/#section-Graph-Literal The lexical value of the literal is the unicode object The interpreted, datatyped value is available from .value Language tags must be valid according to :rfc:5646 For valid XSD datatypes, the lexical form is optionally normalized at construction time. Default behaviour is set by rdflib.NORMALIZE_LITERALS and can be overridden by the normalize parameter to __new__ Equality and hashing of Literals are done based on the lexical form, i.e.: >>> from rdflib.namespace import XSD >>> Literal('01')!=Literal('1') # clear - strings differ True but with data-type they get normalized: >>> Literal('01', datatype=XSD.integer)!=Literal('1', datatype=XSD.integer) False unless disabled: >>> Literal('01', datatype=XSD.integer, normalize=False)!=Literal('1', datatype=XSD.integer) True Value based comparison is possible: >>> Literal('01', datatype=XSD.integer).eq(Literal('1', datatype=XSD.float)) True The eq method also provides limited support for basic python types: >>> Literal(1).eq(1) # fine - int compatible with xsd:integer True >>> Literal('a').eq('b') # fine - str compatible with plain-lit False >>> Literal('a', datatype=XSD.string).eq('a') # fine - str compatible with xsd:string True >>> Literal('a').eq(1) # not fine, int incompatible with plain-lit NotImplemented Greater-than/less-than ordering comparisons are also done in value space, when compatible datatypes are used. Incompatible datatypes are ordered by DT, or by lang-tag. For other nodes the ordering is None < BNode < URIRef < Literal Any comparison with non-rdflib Node are "NotImplemented" In PY2.X some stable order will be made up by python In PY3 this is an error. >>> from rdflib import Literal, XSD >>> lit2006 = Literal('2006-01-01',datatype=XSD.date) >>> lit2006.toPython() datetime.date(2006, 1, 1) >>> lit2006 < Literal('2007-01-01',datatype=XSD.date) True >>> Literal(datetime.utcnow()).datatype rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#dateTime') >>> Literal(1) > Literal(2) # by value False >>> Literal(1) > Literal(2.0) # by value False >>> Literal('1') > Literal(1) # by DT True >>> Literal('1') < Literal('1') # by lexical form False >>> Literal('a', lang='en') > Literal('a', lang='fr') # by lang-tag False >>> Literal(1) > URIRef('foo') # by node-type True The > < operators will eat this NotImplemented and either make up an ordering (py2.x) or throw a TypeError (py3k): >>> Literal(1).__gt__(2.0) NotImplemented """ if not PY3: __slots__ = ("language", "datatype", "value", "_language", "_datatype", "_value") else: __slots__ = ("_language", "_datatype", "_value")
[docs] def __new__(cls, lexical_or_value, lang=None, datatype=None, normalize=None): if lang == '': lang = None # no empty lang-tags in RDF normalize = normalize if normalize != None else rdflib.NORMALIZE_LITERALS if lang is not None and datatype is not None: raise TypeError( "A Literal can only have one of lang or datatype, " "per http://www.w3.org/TR/rdf-concepts/#section-Graph-Literal") if lang and not _is_valid_langtag(lang): raise Exception("'%s' is not a valid language tag!" % lang) if datatype: datatype = URIRef(datatype) value = None if isinstance(lexical_or_value, Literal): # create from another Literal instance lang = lang or lexical_or_value.language if datatype: # override datatype value = _castLexicalToPython(lexical_or_value, datatype) else: datatype = lexical_or_value.datatype value = lexical_or_value.value elif isinstance(lexical_or_value, string_types): # passed a string # try parsing lexical form of datatyped literal value = _castLexicalToPython(lexical_or_value, datatype) if value is not None and normalize: _value, _datatype = _castPythonToLiteral(value) if _value is not None and _is_valid_unicode(_value): lexical_or_value = _value else: # passed some python object value = lexical_or_value _value, _datatype = _castPythonToLiteral(lexical_or_value) datatype = datatype or _datatype if _value is not None: lexical_or_value = _value if datatype: lang = None if PY3 and isinstance(lexical_or_value, bytes): lexical_or_value = lexical_or_value.decode('utf-8') try: inst = text_type.__new__(cls, lexical_or_value) except UnicodeDecodeError: inst = text_type.__new__(cls, lexical_or_value, 'utf-8') inst._language = lang inst._datatype = datatype inst._value = value return inst
[docs] def normalize(self): """ Returns a new literal with a normalised lexical representation of this literal >>> from rdflib import XSD >>> Literal("01", datatype=XSD.integer, normalize=False).normalize() rdflib.term.Literal(u'1', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) Illegal lexical forms for the datatype given are simply passed on >>> Literal("a", datatype=XSD.integer, normalize=False) rdflib.term.Literal(u'a', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) """ if self.value != None: return Literal(self.value, datatype=self.datatype, lang=self.language) else: return self
@property def value(self): return self._value @property def language(self): return self._language @property def datatype(self): return self._datatype
[docs] def __reduce__(self): return (Literal, (text_type(self), self.language, self.datatype),)
[docs] def __getstate__(self): return (None, dict(language=self.language, datatype=self.datatype))
[docs] def __setstate__(self, arg): _, d = arg self._language = d["language"] self._datatype = d["datatype"]
[docs] def __add__(self, val): """ >>> Literal(1) + 1 rdflib.term.Literal(u'2', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> Literal("1") + "1" rdflib.term.Literal(u'11') """ py = self.toPython() if not isinstance(py, Literal): try: return Literal(py + val) except TypeError: pass # fall-through s = text_type.__add__(self, val) return Literal(s, self.language, self.datatype)
[docs] def __bool__(self): """ Is the Literal "True" This is used for if statements, bool(literal), etc. """ if self.value != None: return bool(self.value) return len(self) != 0
if PY2: __nonzero__ = __bool__
[docs] def __neg__(self): """ >>> (- Literal(1)) rdflib.term.Literal(u'-1', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> (- Literal(10.5)) rdflib.term.Literal(u'-10.5', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#double')) >>> from rdflib.namespace import XSD >>> (- Literal("1", datatype=XSD.integer)) rdflib.term.Literal(u'-1', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> (- Literal("1")) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: Not a number; rdflib.term.Literal(u'1') >>> """ if isinstance(self.value, (int, long_type, float)): return Literal(self.value.__neg__()) else: raise TypeError("Not a number; %s" % repr(self))
[docs] def __pos__(self): """ >>> (+ Literal(1)) rdflib.term.Literal(u'1', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> (+ Literal(-1)) rdflib.term.Literal(u'-1', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> from rdflib.namespace import XSD >>> (+ Literal("-1", datatype=XSD.integer)) rdflib.term.Literal(u'-1', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> (+ Literal("1")) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: Not a number; rdflib.term.Literal(u'1') """ if isinstance(self.value, (int, long_type, float)): return Literal(self.value.__pos__()) else: raise TypeError("Not a number; %s" % repr(self))
[docs] def __abs__(self): """ >>> abs(Literal(-1)) rdflib.term.Literal(u'1', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> from rdflib.namespace import XSD >>> abs( Literal("-1", datatype=XSD.integer)) rdflib.term.Literal(u'1', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> abs(Literal("1")) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: Not a number; rdflib.term.Literal(u'1') """ if isinstance(self.value, (int, long_type, float)): return Literal(self.value.__abs__()) else: raise TypeError("Not a number; %s" % repr(self))
[docs] def __invert__(self): """ >>> ~(Literal(-1)) rdflib.term.Literal(u'0', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) >>> from rdflib.namespace import XSD >>> ~( Literal("-1", datatype=XSD.integer)) rdflib.term.Literal(u'0', datatype=rdflib.term.URIRef(u'http://www.w3.org/2001/XMLSchema#integer')) Not working: >>> ~(Literal("1")) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: Not a number; rdflib.term.Literal(u'1') """ if isinstance(self.value, (int, long_type, float)): return Literal(self.value.__invert__()) else: raise TypeError("Not a number; %s" % repr(self))
[docs] def __gt__(self, other): """ This implements ordering for Literals, the other comparison methods delegate here This tries to implement this: http://www.w3.org/TR/sparql11-query/#modOrderBy In short, Literals with compatible data-types are ordered in value space, i.e. >>> from rdflib import XSD >>> Literal(1) > Literal(2) # int/int False >>> Literal(2.0) > Literal(1) # double/int True >>> from decimal import Decimal >>> Literal(Decimal("3.3")) > Literal(2.0) # decimal/double True >>> Literal(Decimal("3.3")) < Literal(4.0) # decimal/double True >>> Literal('b') > Literal('a') # plain lit/plain lit True >>> Literal('b') > Literal('a', datatype=XSD.string) # plain lit/xsd:str True Incompatible datatype mismatches ordered by DT >>> Literal(1) > Literal("2") # int>string False Langtagged literals by lang tag >>> Literal("a", lang="en") > Literal("a", lang="fr") False """ if other is None: return True # Everything is greater than None if isinstance(other, Literal): if self.datatype in _NUMERIC_LITERAL_TYPES and \ other.datatype in _NUMERIC_LITERAL_TYPES: return self.value > other.value # plain-literals and xsd:string literals # are "the same" dtself = self.datatype or _XSD_STRING dtother = other.datatype or _XSD_STRING if dtself != dtother: if rdflib.DAWG_LITERAL_COLLATION: return NotImplemented else: return dtself > dtother if self.language != other.language: if not self.language: return False elif not other.language: return True else: return self.language > other.language if self.value is not None and other.value is not None: if type(self.value) in _TOTAL_ORDER_CASTERS: caster = _TOTAL_ORDER_CASTERS[type(self.value)] return caster(self.value) > caster(other.value) return self.value > other.value if text_type(self) != text_type(other): return text_type(self) > text_type(other) # same language, same lexical form, check real dt # plain-literals come before xsd:string! if self.datatype != other.datatype: if not self.datatype: return False elif not other.datatype: return True else: return self.datatype > other.datatype return False # they are the same elif isinstance(other, Node): return True # Literal are the greatest! else: return NotImplemented # we can only compare to nodes
[docs] def __lt__(self, other): if other is None: return False # Nothing is less than None if isinstance(other, Literal): try: return not self.__gt__(other) and not self.eq(other) except TypeError: return NotImplemented if isinstance(other, Node): return False # all nodes are less-than Literals return NotImplemented
[docs] def __le__(self, other): """ >>> from rdflib.namespace import XSD >>> Literal('2007-01-01T10:00:00', datatype=XSD.dateTime ... ) <= Literal('2007-01-01T10:00:00', datatype=XSD.dateTime) True """ r = self.__lt__(other) if r: return True try: return self.eq(other) except TypeError: return NotImplemented
[docs] def __ge__(self, other): r = self.__gt__(other) if r: return True try: return self.eq(other) except TypeError: return NotImplemented
def _comparable_to(self, other): """ Helper method to decide which things are meaningful to rich-compare with this literal """ if isinstance(other, Literal): if (self.datatype and other.datatype): # two datatyped literals if not self.datatype in XSDToPython or not other.datatype in XSDToPython: # non XSD DTs must match if self.datatype != other.datatype: return False else: # xsd:string may be compared with plain literals if not (self.datatype == _XSD_STRING and not other.datatype) or \ (other.datatype == _XSD_STRING and not self.datatype): return False # if given lang-tag has to be case insensitive equal if (self.language or "").lower() != (other.language or "").lower(): return False return True
[docs] def __hash__(self): """ >>> from rdflib.namespace import XSD >>> a = {Literal('1', datatype=XSD.integer):'one'} >>> Literal('1', datatype=XSD.double) in a False "Called for the key object for dictionary operations, and by the built-in function hash(). Should return a 32-bit integer usable as a hash value for dictionary operations. The only required property is that objects which compare equal have the same hash value; it is advised to somehow mix together (e.g., using exclusive or) the hash values for the components of the object that also play a part in comparison of objects." -- 3.4.1 Basic customization (Python) "Two literals are equal if and only if all of the following hold: * The strings of the two lexical forms compare equal, character by character. * Either both or neither have language tags. * The language tags, if any, compare equal. * Either both or neither have datatype URIs. * The two datatype URIs, if any, compare equal, character by character." -- 6.5.1 Literal Equality (RDF: Concepts and Abstract Syntax) """ # don't use super()... for efficiency reasons, see Identifier.__hash__ res = text_type.__hash__(self) if self.language: res ^= hash(self.language.lower()) if self.datatype: res ^= hash(self.datatype) return res
[docs] def __eq__(self, other): """ Literals are only equal to other literals. "Two literals are equal if and only if all of the following hold: * The strings of the two lexical forms compare equal, character by character. * Either both or neither have language tags. * The language tags, if any, compare equal. * Either both or neither have datatype URIs. * The two datatype URIs, if any, compare equal, character by character." -- 6.5.1 Literal Equality (RDF: Concepts and Abstract Syntax) >>> Literal("1", datatype=URIRef("foo")) == Literal("1", datatype=URIRef("foo")) True >>> Literal("1", datatype=URIRef("foo")) == Literal("1", datatype=URIRef("foo2")) False >>> Literal("1", datatype=URIRef("foo")) == Literal("2", datatype=URIRef("foo")) False >>> Literal("1", datatype=URIRef("foo")) == "asdf" False >>> from rdflib import XSD >>> Literal('2007-01-01', datatype=XSD.date) == Literal('2007-01-01', datatype=XSD.date) True >>> Literal('2007-01-01', datatype=XSD.date) == date(2007, 1, 1) False >>> Literal("one", lang="en") == Literal("one", lang="en") True >>> Literal("hast", lang='en') == Literal("hast", lang='de') False >>> Literal("1", datatype=XSD.integer) == Literal(1) True >>> Literal("1", datatype=XSD.integer) == Literal("01", datatype=XSD.integer) True """ if self is other: return True if other is None: return False if isinstance(other, Literal): return self.datatype == other.datatype \ and (self.language.lower() if self.language else None) == (other.language.lower() if other.language else None) \ and text_type.__eq__(self, other) return False
[docs] def eq(self, other): """ Compare the value of this literal with something else Either, with the value of another literal comparisons are then done in literal "value space", and according to the rules of XSD subtype-substitution/type-promotion OR, with a python object: basestring objects can be compared with plain-literals, or those with datatype xsd:string bool objects with xsd:boolean a int, long or float with numeric xsd types isodate date,time,datetime objects with xsd:date,xsd:time or xsd:datetime Any other operations returns NotImplemented """ if isinstance(other, Literal): if self.datatype in _NUMERIC_LITERAL_TYPES \ and other.datatype in _NUMERIC_LITERAL_TYPES: if self.value != None and other.value != None: return self.value == other.value else: if text_type.__eq__(self, other): return True raise TypeError( 'I cannot know that these two lexical forms do not map to the same value: %s and %s' % (self, other)) if (self.language or "").lower() != (other.language or "").lower(): return False dtself = self.datatype or _XSD_STRING dtother = other.datatype or _XSD_STRING if (dtself == _XSD_STRING and dtother == _XSD_STRING): # string/plain literals, compare on lexical form return text_type.__eq__(self, other) if dtself != dtother: if rdflib.DAWG_LITERAL_COLLATION: raise TypeError("I don't know how to compare literals with datatypes %s and %s" % ( self.datatype, other.datatype)) else: return False # matching non-string DTs now - do we compare values or # lexical form first? comparing two ints is far quicker - # maybe there are counter examples if self.value != None and other.value != None: if self.datatype in (_RDF_XMLLITERAL, _RDF_HTMLLITERAL): return _isEqualXMLNode(self.value, other.value) return self.value == other.value else: if text_type.__eq__(self, other): return True if self.datatype == _XSD_STRING: return False # string value space=lexical space # matching DTs, but not matching, we cannot compare! raise TypeError( 'I cannot know that these two lexical forms do not map to the same value: %s and %s' % (self, other)) elif isinstance(other, Node): return False # no non-Literal nodes are equal to a literal elif isinstance(other, string_types): # only plain-literals can be directly compared to strings # TODO: Is "blah"@en eq "blah" ? if self.language is not None: return False if (self.datatype == _XSD_STRING or self.datatype is None): return text_type(self) == other elif isinstance(other, (int, long_type, float)): if self.datatype in _NUMERIC_LITERAL_TYPES: return self.value == other elif isinstance(other, (date, datetime, time)): if self.datatype in (_XSD_DATETIME, _XSD_DATE, _XSD_TIME): return self.value == other elif isinstance(other, (timedelta, Duration)): if self.datatype in (_XSD_DURATION, _XSD_DAYTIMEDURATION, _XSD_YEARMONTHDURATION): return self.value == other elif isinstance(other, bool): if self.datatype == _XSD_BOOLEAN: return self.value == other return NotImplemented
[docs] def neq(self, other): return not self.eq(other)
[docs] def n3(self, namespace_manager=None): r''' Returns a representation in the N3 format. Examples:: >>> Literal("foo").n3() u'"foo"' Strings with newlines or triple-quotes:: >>> Literal("foo\nbar").n3() u'"""foo\nbar"""' >>> Literal("''\'").n3() u'"\'\'\'"' >>> Literal('"""').n3() u'"\\"\\"\\""' Language:: >>> Literal("hello", lang="en").n3() u'"hello"@en' Datatypes:: >>> Literal(1).n3() u'"1"^^<http://www.w3.org/2001/XMLSchema#integer>' >>> Literal(1.0).n3() u'"1.0"^^<http://www.w3.org/2001/XMLSchema#double>' >>> Literal(True).n3() u'"true"^^<http://www.w3.org/2001/XMLSchema#boolean>' Datatype and language isn't allowed (datatype takes precedence):: >>> Literal(1, lang="en").n3() u'"1"^^<http://www.w3.org/2001/XMLSchema#integer>' Custom datatype:: >>> footype = URIRef("http://example.org/ns#foo") >>> Literal("1", datatype=footype).n3() u'"1"^^<http://example.org/ns#foo>' Passing a namespace-manager will use it to abbreviate datatype URIs: >>> from rdflib import Graph >>> Literal(1).n3(Graph().namespace_manager) u'"1"^^xsd:integer' ''' if namespace_manager: return self._literal_n3(qname_callback=namespace_manager.normalizeUri) else: return self._literal_n3()
def _literal_n3(self, use_plain=False, qname_callback=None): ''' Using plain literal (shorthand) output:: >>> from rdflib.namespace import XSD >>> Literal(1)._literal_n3(use_plain=True) u'1' >>> Literal(1.0)._literal_n3(use_plain=True) u'1e+00' >>> Literal(1.0, datatype=XSD.decimal)._literal_n3(use_plain=True) u'1.0' >>> Literal(1.0, datatype=XSD.float)._literal_n3(use_plain=True) u'"1.0"^^<http://www.w3.org/2001/XMLSchema#float>' >>> Literal("foo", datatype=XSD.string)._literal_n3( ... use_plain=True) u'"foo"^^<http://www.w3.org/2001/XMLSchema#string>' >>> Literal(True)._literal_n3(use_plain=True) u'true' >>> Literal(False)._literal_n3(use_plain=True) u'false' >>> Literal(1.91)._literal_n3(use_plain=True) u'1.91e+00' Only limited precision available for floats: >>> Literal(0.123456789)._literal_n3(use_plain=True) u'1.234568e-01' >>> Literal('0.123456789', ... datatype=XSD.decimal)._literal_n3(use_plain=True) u'0.123456789' Using callback for datatype QNames:: >>> Literal(1)._literal_n3( ... qname_callback=lambda uri: "xsd:integer") u'"1"^^xsd:integer' ''' if use_plain and self.datatype in _PLAIN_LITERAL_TYPES: if self.value is not None: # If self is inf or NaN, we need a datatype # (there is no plain representation) if self.datatype in _NUMERIC_INF_NAN_LITERAL_TYPES: try: v = float(self) if math.isinf(v) or math.isnan(v): return self._literal_n3(False, qname_callback) except ValueError: return self._literal_n3(False, qname_callback) # this is a bit of a mess - # in py >=2.6 the string.format function makes this easier # we try to produce "pretty" output if self.datatype == _XSD_DOUBLE: return sub("\\.?0*e", "e", u'%e' % float(self)) elif self.datatype == _XSD_DECIMAL: s = '%s' % self if '.' not in s: s += '.0' return s elif self.datatype == _XSD_BOOLEAN: return (u'%s' % self).lower() else: return u'%s' % self encoded = self._quote_encode() datatype = self.datatype quoted_dt = None if datatype: if qname_callback: quoted_dt = qname_callback(datatype) if not quoted_dt: quoted_dt = "<%s>" % datatype if datatype in _NUMERIC_INF_NAN_LITERAL_TYPES: try: v = float(self) if math.isinf(v): # py string reps: float: 'inf', Decimal: 'Infinity" # both need to become "INF" in xsd datatypes encoded = encoded.replace('inf', 'INF').replace( 'Infinity', 'INF') if math.isnan(v): encoded = encoded.replace('nan', 'NaN') except ValueError: # if we can't cast to float something is wrong, but we can # still serialize. Warn user about it warnings.warn("Serializing weird numerical %r" % self) language = self.language if language: return '%s@%s' % (encoded, language) elif datatype: return '%s^^%s' % (encoded, quoted_dt) else: return '%s' % encoded def _quote_encode(self): # This simpler encoding doesn't work; a newline gets encoded as "\\n", # which is ok in sourcecode, but we want "\n". # encoded = self.encode('unicode-escape').replace( # '\\', '\\\\').replace('"','\\"') # encoded = self.replace.replace('\\', '\\\\').replace('"','\\"') # NOTE: Could in theory chose quotes based on quotes appearing in the # string, i.e. '"' and "'", but N3/turtle doesn't allow "'"(?). if "\n" in self: # Triple quote this string. encoded = self.replace('\\', '\\\\') if '"""' in self: # is this ok? encoded = encoded.replace('"""', '\\"\\"\\"') if encoded[-1] == '"' and encoded[-2] != '\\': encoded = encoded[:-1] + '\\' + '"' return '"""%s"""' % encoded.replace('\r', '\\r') else: return '"%s"' % self.replace( '\n', '\\n').replace( '\\', '\\\\').replace( '"', '\\"').replace( '\r', '\\r') if PY2:
[docs] def __str__(self): return self.encode()
[docs] def __repr__(self): args = [super(Literal, self).__repr__()] if self.language is not None: args.append("lang=%s" % repr(self.language)) if self.datatype is not None: args.append("datatype=%s" % repr(self.datatype)) if self.__class__ == Literal: clsName = "rdflib.term.Literal" else: clsName = self.__class__.__name__ return """%s(%s)""" % (clsName, ", ".join(args))
[docs] def toPython(self): """ Returns an appropriate python datatype derived from this RDF Literal """ if self.value is not None: return self.value return self
def _parseXML(xmlstring): if PY2: xmlstring = xmlstring.encode('utf-8') retval = xml.dom.minidom.parseString( "<rdflibtoplevelelement>%s</rdflibtoplevelelement>" % xmlstring) retval.normalize() return retval def _parseHTML(htmltext): try: import html5lib parser = html5lib.HTMLParser( tree=html5lib.treebuilders.getTreeBuilder("dom")) retval = parser.parseFragment(htmltext) retval.normalize() return retval except ImportError: raise ImportError( "HTML5 parser not available. Try installing" + " html5lib <http://code.google.com/p/html5lib>") def _writeXML(xmlnode): if isinstance(xmlnode, xml.dom.minidom.DocumentFragment): d = xml.dom.minidom.Document() d.childNodes += xmlnode.childNodes xmlnode = d s = xmlnode.toxml('utf-8') # for clean round-tripping, remove headers -- I have great and # specific worries that this will blow up later, but this margin # is too narrow to contain them if s.startswith(b('<?xml version="1.0" encoding="utf-8"?>')): s = s[38:] if s.startswith(b('<rdflibtoplevelelement>')): s = s[23:-24] if s == b('<rdflibtoplevelelement/>'): s = b('') return s # Cannot import Namespace/XSD because of circular dependencies _XSD_PFX = 'http://www.w3.org/2001/XMLSchema#' _RDF_PFX = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#' _RDF_XMLLITERAL = URIRef(_RDF_PFX + 'XMLLiteral') _RDF_HTMLLITERAL = URIRef(_RDF_PFX + 'HTML') _XSD_STRING = URIRef(_XSD_PFX + 'string') _XSD_FLOAT = URIRef(_XSD_PFX + 'float') _XSD_DOUBLE = URIRef(_XSD_PFX + 'double') _XSD_DECIMAL = URIRef(_XSD_PFX + 'decimal') _XSD_INTEGER = URIRef(_XSD_PFX + 'integer') _XSD_BOOLEAN = URIRef(_XSD_PFX + 'boolean') _XSD_DATETIME = URIRef(_XSD_PFX + 'dateTime') _XSD_DATE = URIRef(_XSD_PFX + 'date') _XSD_TIME = URIRef(_XSD_PFX + 'time') _XSD_DURATION = URIRef(_XSD_PFX + 'duration') _XSD_DAYTIMEDURATION = URIRef(_XSD_PFX + 'dayTimeDuration') _XSD_YEARMONTHDURATION = URIRef(_XSD_PFX + 'yearMonthDuration') # TODO: gYearMonth, gYear, gMonthDay, gDay, gMonth _NUMERIC_LITERAL_TYPES = ( _XSD_INTEGER, _XSD_DECIMAL, _XSD_DOUBLE, URIRef(_XSD_PFX + 'float'), URIRef(_XSD_PFX + 'byte'), URIRef(_XSD_PFX + 'int'), URIRef(_XSD_PFX + 'long'), URIRef(_XSD_PFX + 'negativeInteger'), URIRef(_XSD_PFX + 'nonNegativeInteger'), URIRef(_XSD_PFX + 'nonPositiveInteger'), URIRef(_XSD_PFX + 'positiveInteger'), URIRef(_XSD_PFX + 'short'), URIRef(_XSD_PFX + 'unsignedByte'), URIRef(_XSD_PFX + 'unsignedInt'), URIRef(_XSD_PFX + 'unsignedLong'), URIRef(_XSD_PFX + 'unsignedShort'), ) # these have "native" syntax in N3/SPARQL _PLAIN_LITERAL_TYPES = ( _XSD_INTEGER, _XSD_BOOLEAN, _XSD_DOUBLE, _XSD_DECIMAL, ) # these have special INF and NaN XSD representations _NUMERIC_INF_NAN_LITERAL_TYPES = ( URIRef(_XSD_PFX + 'float'), _XSD_DOUBLE, _XSD_DECIMAL, ) # the following types need special treatment for reasonable sorting because # certain instances can't be compared to each other. We treat this by # partitioning and then sorting within those partitions. _TOTAL_ORDER_CASTERS = { datetime: lambda value: ( # naive vs. aware value.tzinfo is not None and value.tzinfo.utcoffset(value) is not None, value ), time: lambda value: ( # naive vs. aware value.tzinfo is not None and value.tzinfo.utcoffset(None) is not None, value ), xml.dom.minidom.Document: lambda value: value.toxml(), }
[docs]def _castPythonToLiteral(obj): """ Casts a python datatype to a tuple of the lexical value and a datatype URI (or None) """ for pType, (castFunc, dType) in _PythonToXSD: if isinstance(obj, pType): if castFunc: return castFunc(obj), dType elif dType: return obj, dType else: return obj, None return obj, None # TODO: is this right for the fall through case?
from decimal import Decimal # Mappings from Python types to XSD datatypes and back (borrowed from sparta) # datetime instances are also instances of date... so we need to order these. # SPARQL/Turtle/N3 has shortcuts for integer, double, decimal # python has only float - to be in tune with sparql/n3/turtle # we default to XSD.double for float literals # python ints are promoted to longs when overflowing # python longs have no limit # both map to the abstract integer type, # rather than some concrete bit-limited datatype _PythonToXSD = [ (string_types, (None, None)), (float, (None, _XSD_DOUBLE)), (bool, (lambda i:str(i).lower(), _XSD_BOOLEAN)), (int, (None, _XSD_INTEGER)), (long_type, (None, _XSD_INTEGER)), (Decimal, (None, _XSD_DECIMAL)), (datetime, (lambda i:i.isoformat(), _XSD_DATETIME)), (date, (lambda i:i.isoformat(), _XSD_DATE)), (time, (lambda i:i.isoformat(), _XSD_TIME)), (Duration, (lambda i:duration_isoformat(i), _XSD_DURATION)), (timedelta, (lambda i:duration_isoformat(i), _XSD_DAYTIMEDURATION)), (xml.dom.minidom.Document, (_writeXML, _RDF_XMLLITERAL)), # this is a bit dirty - by accident the html5lib parser produces # DocumentFragments, and the xml parser Documents, letting this # decide what datatype to use makes roundtripping easier, but it a # bit random (xml.dom.minidom.DocumentFragment, (_writeXML, _RDF_HTMLLITERAL)) ] XSDToPython = { None: None, # plain literals map directly to value space URIRef(_XSD_PFX + 'time'): parse_time, URIRef(_XSD_PFX + 'date'): parse_date, URIRef(_XSD_PFX + 'gYear'): parse_date, URIRef(_XSD_PFX + 'gYearMonth'): parse_date, URIRef(_XSD_PFX + 'dateTime'): parse_datetime, URIRef(_XSD_PFX + 'duration'): parse_duration, URIRef(_XSD_PFX + 'dayTimeDuration'): parse_duration, URIRef(_XSD_PFX + 'yearMonthDuration'): parse_duration, URIRef(_XSD_PFX + 'string'): None, URIRef(_XSD_PFX + 'normalizedString'): None, URIRef(_XSD_PFX + 'token'): None, URIRef(_XSD_PFX + 'language'): None, URIRef(_XSD_PFX + 'boolean'): lambda i: i.lower() == 'true', URIRef(_XSD_PFX + 'decimal'): Decimal, URIRef(_XSD_PFX + 'integer'): long_type, URIRef(_XSD_PFX + 'nonPositiveInteger'): int, URIRef(_XSD_PFX + 'long'): long_type, URIRef(_XSD_PFX + 'nonNegativeInteger'): int, URIRef(_XSD_PFX + 'negativeInteger'): int, URIRef(_XSD_PFX + 'int'): long_type, URIRef(_XSD_PFX + 'unsignedLong'): long_type, URIRef(_XSD_PFX + 'positiveInteger'): int, URIRef(_XSD_PFX + 'short'): int, URIRef(_XSD_PFX + 'unsignedInt'): long_type, URIRef(_XSD_PFX + 'byte'): int, URIRef(_XSD_PFX + 'unsignedShort'): int, URIRef(_XSD_PFX + 'unsignedByte'): int, URIRef(_XSD_PFX + 'float'): float, URIRef(_XSD_PFX + 'double'): float, URIRef(_XSD_PFX + 'base64Binary'): lambda s: base64.b64decode(s), URIRef(_XSD_PFX + 'anyURI'): None, _RDF_XMLLITERAL: _parseXML, _RDF_HTMLLITERAL: _parseHTML } _toPythonMapping = {} _toPythonMapping.update(XSDToPython)
[docs]def _castLexicalToPython(lexical, datatype): """ Map a lexical form to the value-space for the given datatype :returns: a python object for the value or ``None`` """ convFunc = _toPythonMapping.get(datatype, False) if convFunc: try: return convFunc(lexical) except: # not a valid lexical representation for this dt return None elif convFunc is None: # no conv func means 1-1 lexical<->value-space mapping try: return text_type(lexical) except UnicodeDecodeError: return text_type(lexical, 'utf-8') else: # no convFunc - unknown data-type return None
[docs]def bind(datatype, pythontype, constructor=None, lexicalizer=None): """ register a new datatype<->pythontype binding :param constructor: an optional function for converting lexical forms into a Python instances, if not given the pythontype is used directly :param lexicalizer: an optinoal function for converting python objects to lexical form, if not given object.__str__ is used """ if datatype in _toPythonMapping: logger.warning("datatype '%s' was already bound. Rebinding." % datatype) if constructor == None: constructor = pythontype _toPythonMapping[datatype] = constructor _PythonToXSD.append((pythontype, (lexicalizer, datatype)))
[docs]class Variable(Identifier): """ A Variable - this is used for querying, or in Formula aware graphs, where Variables can stored in the graph """ __slots__ = ()
[docs] def __new__(cls, value): if len(value) == 0: raise Exception( "Attempted to create variable with empty string as name!") if value[0] == '?': value = value[1:] return text_type.__new__(cls, value)
[docs] def __repr__(self): if self.__class__ is Variable: clsName = "rdflib.term.Variable" else: clsName = self.__class__.__name__ return """%s(%s)""" % (clsName, super(Variable, self).__repr__())
[docs] def toPython(self): return "?%s" % self
[docs] def n3(self, namespace_manager=None): return "?%s" % self
[docs] def __reduce__(self): return (Variable, (text_type(self),))
[docs]class Statement(Node, tuple):
[docs] def __new__(cls, triple, context): subject, predicate, object = triple warnings.warn( "Class Statement is deprecated, and will be removed in " + "the future. If you use this please let rdflib-dev know!", category=DeprecationWarning, stacklevel=2) return tuple.__new__(cls, ((subject, predicate, object), context))
[docs] def __reduce__(self): return (Statement, (self[0], self[1]))
[docs] def toPython(self): return (self[0], self[1])
# Nodes are ordered like this # See http://www.w3.org/TR/sparql11-query/#modOrderBy # we leave "space" for more subclasses of Node elsewhere # default-dict to grazefully fail for new subclasses _ORDERING = defaultdict(int) _ORDERING.update({ BNode: 10, Variable: 20, URIRef: 30, Literal: 40 }) def _isEqualXMLNode(node, other): from xml.dom.minidom import Node def recurse(): # Recursion through the children # In Python2, the semantics of 'map' is such that the check on # length would be unnecessary. In Python 3, # the semantics of map has changed (why, oh why???) and the check # for the length becomes necessary... if len(node.childNodes) != len(other.childNodes): return False for (nc, oc) in map( lambda x, y: (x, y), node.childNodes, other.childNodes): if not _isEqualXMLNode(nc, oc): return False # if we got here then everything is fine: return True if node is None or other is None: return False if node.nodeType != other.nodeType: return False if node.nodeType in [Node.DOCUMENT_NODE, Node.DOCUMENT_FRAGMENT_NODE]: return recurse() elif node.nodeType == Node.ELEMENT_NODE: # Get the basics right if not (node.tagName == other.tagName and node.namespaceURI == other.namespaceURI): return False # Handle the (namespaced) attributes; the namespace setting key # should be ignored, though # Note that the minidom orders the keys already, so we do not have # to worry about that, which is a bonus... n_keys = [ k for k in node.attributes.keysNS() if k[0] != 'http://www.w3.org/2000/xmlns/'] o_keys = [ k for k in other.attributes.keysNS() if k[0] != 'http://www.w3.org/2000/xmlns/'] if len(n_keys) != len(o_keys): return False for k in n_keys: if not (k in o_keys and node.getAttributeNS(k[0], k[1]) == other.getAttributeNS(k[0], k[1])): return False # if we got here, the attributes are all right, we can go down # the tree recursively return recurse() elif node.nodeType in [ Node.TEXT_NODE, Node.COMMENT_NODE, Node.CDATA_SECTION_NODE, Node.NOTATION_NODE]: return node.data == other.data elif node.nodeType == Node.PROCESSING_INSTRUCTION_NODE: return node.data == other.data and node.target == other.target elif node.nodeType == Node.ENTITY_NODE: return node.nodeValue == other.nodeValue elif node.nodeType == Node.DOCUMENT_TYPE_NODE: return node.publicId == other.publicId \ and node.systemId == other.system.Id else: # should not happen, in fact raise Exception( 'I dont know how to compare XML Node type: %s' % node.nodeType) if __name__ == '__main__': import doctest doctest.testmod()