# -*- coding: utf-8 -*-
"""
The core parsing function of RDFa. Some details are
put into other modules to make it clearer to update/modify (e.g., generation of C{@property} values, or managing the current state).
Note that the entry point (L{parse_one_node}) bifurcates into an RDFa 1.0 and RDFa 1.1 version, ie,
to L{_parse_1_0} and L{_parse_1_1}. Some of the parsing details (management of C{@property}, list facilities, changed behavior on C{@typeof})) have changed
between versions and forcing the two into one function would be counter productive.
@summary: RDFa core parser processing step
@organization: U{World Wide Web Consortium<http://www.w3.org>}
@author: U{Ivan Herman<a href="http://www.w3.org/People/Ivan/">}
@license: This software is available for use under the
U{W3C® SOFTWARE NOTICE AND LICENSE<href="http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231">}
"""
"""
$Id: parse.py,v 1.19 2013-01-07 12:46:43 ivan Exp $
$Date: 2013-01-07 12:46:43 $
"""
import sys
from .state import ExecutionContext
from .property import ProcessProperty
from .embeddedRDF import handle_embeddedRDF
from .host import HostLanguage, host_dom_transforms
import rdflib
from rdflib import URIRef
from rdflib import Literal
from rdflib import BNode
from rdflib import Namespace
if rdflib.__version__ >= "3.0.0" :
from rdflib import Graph
from rdflib import RDF as ns_rdf
from rdflib import RDFS as ns_rdfs
else :
from rdflib.Graph import Graph
from rdflib.RDFS import RDFSNS as ns_rdfs
from rdflib.RDF import RDFNS as ns_rdf
from . import IncorrectBlankNodeUsage, err_no_blank_node
from .utils import has_one_of_attributes
#######################################################################
[docs]def parse_one_node(node, graph, parent_object, incoming_state, parent_incomplete_triples) :
"""The (recursive) step of handling a single node.
This entry just switches between the RDFa 1.0 and RDFa 1.1 versions for parsing. This method is only invoked once,
actually, from the top level; the recursion then happens in the L{_parse_1_0} and L{_parse_1_1} methods for
RDFa 1.0 and RDFa 1.1, respectively.
@param node: the DOM node to handle
@param graph: the RDF graph
@type graph: RDFLib's Graph object instance
@param parent_object: the parent's object, as an RDFLib URIRef
@param incoming_state: the inherited state (namespaces, lang, etc.)
@type incoming_state: L{state.ExecutionContext}
@param parent_incomplete_triples: list of hanging triples (the missing resource set to None) to be handled (or not)
by the current node.
@return: whether the caller has to complete it's parent's incomplete triples
@rtype: Boolean
"""
# Branch according to versions.
if incoming_state.rdfa_version >= "1.1" :
_parse_1_1(node, graph, parent_object, incoming_state, parent_incomplete_triples)
else :
_parse_1_0(node, graph, parent_object, incoming_state, parent_incomplete_triples)
#######################################################################
def _parse_1_1(node, graph, parent_object, incoming_state, parent_incomplete_triples) :
"""The (recursive) step of handling a single node. See the
U{RDFa 1.1 Core document<http://www.w3.org/TR/rdfa-core/>} for further details.
This is the RDFa 1.1 version.
@param node: the DOM node to handle
@param graph: the RDF graph
@type graph: RDFLib's Graph object instance
@param parent_object: the parent's object, as an RDFLib URIRef
@param incoming_state: the inherited state (namespaces, lang, etc.)
@type incoming_state: L{state.ExecutionContext}
@param parent_incomplete_triples: list of hanging triples (the missing resource set to None) to be handled (or not)
by the current node.
@return: whether the caller has to complete it's parent's incomplete triples
@rtype: Boolean
"""
def header_check(p_obj) :
"""Special disposition for the HTML <head> and <body> elements..."""
if state.options.host_language in [ HostLanguage.xhtml, HostLanguage.html5, HostLanguage.xhtml5 ] :
if node.nodeName == "head" or node.nodeName == "body" :
if not has_one_of_attributes(node, "about", "resource", "src", "href") :
return p_obj
else :
return None
def lite_check() :
if state.options.check_lite and state.options.host_language in [ HostLanguage.html5, HostLanguage.xhtml5, HostLanguage.xhtml ] :
if node.tagName == "link" and node.hasAttribute("rel") and state.term_or_curie.CURIE_to_URI(node.getAttribute("rel")) != None :
state.options.add_warning("In RDFa Lite, attribute @rel in <link> is only used in non-RDFa way (consider using @property)", node=node)
# Update the state. This means, for example, the possible local settings of
# namespaces and lang
state = None
state = ExecutionContext(node, graph, inherited_state=incoming_state)
#---------------------------------------------------------------------------------
# Extra warning check on RDFa Lite
lite_check()
#---------------------------------------------------------------------------------
# Handling the role attribute is pretty much orthogonal to everything else...
handle_role_attribute(node, graph, state)
#---------------------------------------------------------------------------------
# Handle the special case for embedded RDF, eg, in SVG1.2.
# This may add some triples to the target graph that does not originate from RDFa parsing
# If the function return TRUE, that means that an rdf:RDF has been found. No
# RDFa parsing should be done on that subtree, so we simply return...
if state.options.embedded_rdf and node.nodeType == node.ELEMENT_NODE and handle_embeddedRDF(node, graph, state) :
return
#---------------------------------------------------------------------------------
# calling the host language specific massaging of the DOM
if state.options.host_language in host_dom_transforms and node.nodeType == node.ELEMENT_NODE :
for func in host_dom_transforms[state.options.host_language] : func(node, state)
#---------------------------------------------------------------------------------
# First, let us check whether there is anything to do at all. Ie,
# whether there is any relevant RDFa specific attribute on the element
#
if not has_one_of_attributes(node, "href", "resource", "about", "property", "rel", "rev", "typeof", "src", "vocab", "prefix") :
# nop, there is nothing to do here, just go down the tree and return...
for n in node.childNodes :
if n.nodeType == node.ELEMENT_NODE : parse_one_node(n, graph, parent_object, state, parent_incomplete_triples)
return
#-----------------------------------------------------------------
# The goal is to establish the subject and object for local processing
# The behaviour is slightly different depending on the presense or not
# of the @rel/@rev attributes
current_subject = None
current_object = None
typed_resource = None
if has_one_of_attributes(node, "rel", "rev") :
# in this case there is the notion of 'left' and 'right' of @rel/@rev
# in establishing the new Subject and the objectResource
current_subject = header_check(parent_object)
# set first the subject
if node.hasAttribute("about") :
current_subject = state.getURI("about")
if node.hasAttribute("typeof") : typed_resource = current_subject
# get_URI may return None in case of an illegal CURIE, so
# we have to be careful here, not use only an 'else'
if current_subject == None :
current_subject = parent_object
else :
state.reset_list_mapping(origin = current_subject)
# set the object resource
current_object = state.getResource("resource", "href", "src")
if node.hasAttribute("typeof") and not node.hasAttribute("about") :
if current_object == None :
current_object = BNode()
typed_resource = current_object
if not node.hasAttribute("inlist") and current_object != None :
# In this case the newly defined object is, in fact, the head of the list
# just reset the whole thing.
state.reset_list_mapping(origin = current_object)
elif node.hasAttribute("property") and not has_one_of_attributes(node, "content", "datatype") :
current_subject = header_check(parent_object)
# this is the case when the property may take hold of @src and friends...
if node.hasAttribute("about") :
current_subject = state.getURI("about")
if node.hasAttribute("typeof") : typed_resource = current_subject
# getURI may return None in case of an illegal CURIE, so
# we have to be careful here, not use only an 'else'
if current_subject == None :
current_subject = parent_object
else :
state.reset_list_mapping(origin = current_subject)
if typed_resource == None and node.hasAttribute("typeof") :
typed_resource = state.getResource("resource", "href", "src")
if typed_resource == None :
typed_resource = BNode()
current_object = typed_resource
else :
current_object = current_subject
else :
current_subject = header_check(parent_object)
# in this case all the various 'resource' setting attributes
# behave identically, though they also have their own priority
if current_subject == None :
current_subject = state.getResource("about", "resource", "href", "src")
# get_URI_ref may return None in case of an illegal CURIE, so
# we have to be careful here, not use only an 'else'
if current_subject == None :
if node.hasAttribute("typeof") :
current_subject = BNode()
state.reset_list_mapping(origin = current_subject)
else :
current_subject = parent_object
else :
state.reset_list_mapping(origin = current_subject)
# in this case no non-literal triples will be generated, so the
# only role of the current_object Resource is to be transferred to
# the children node
current_object = current_subject
if node.hasAttribute("typeof") : typed_resource = current_subject
# ---------------------------------------------------------------------
## The possible typeof indicates a number of type statements on the typed resource
for defined_type in state.getURI("typeof") :
if typed_resource :
graph.add((typed_resource, ns_rdf["type"], defined_type))
# ---------------------------------------------------------------------
# In case of @rel/@rev, either triples or incomplete triples are generated
# the (possible) incomplete triples are collected, to be forwarded to the children
incomplete_triples = []
for prop in state.getURI("rel") :
if not isinstance(prop,BNode) :
if node.hasAttribute("inlist") :
if current_object != None :
# Add the content to the list. Note that if the same list
# was initialized, at some point, by a None, it will be
# overwritten by this real content
state.add_to_list_mapping(prop, current_object)
else :
# Add a dummy entry to the list... Note that
# if that list was initialized already with a real content
# this call will have no effect
state.add_to_list_mapping(prop, None)
# Add a placeholder into the hanging rels
incomplete_triples.append( (None, prop, None) )
else :
theTriple = (current_subject, prop, current_object)
if current_object != None :
graph.add(theTriple)
else :
incomplete_triples.append(theTriple)
else :
state.options.add_warning(err_no_blank_node % "rel", warning_type=IncorrectBlankNodeUsage, node=node.nodeName)
for prop in state.getURI("rev") :
if not isinstance(prop,BNode) :
theTriple = (current_object,prop,current_subject)
if current_object != None :
graph.add(theTriple)
else :
incomplete_triples.append(theTriple)
else :
state.options.add_warning(err_no_blank_node % "rev", warning_type=IncorrectBlankNodeUsage, node=node.nodeName)
# ----------------------------------------------------------------------
# Generation of the @property values, including literals. The newSubject is the subject
# A particularity of property is that it stops the parsing down the DOM tree if an XML Literal is generated,
# because everything down there is part of the generated literal.
if node.hasAttribute("property") :
ProcessProperty(node, graph, current_subject, state, typed_resource).generate_1_1()
# ----------------------------------------------------------------------
# Setting the current object to a bnode is setting up a possible resource
# for the incomplete triples downwards
if current_object == None :
object_to_children = BNode()
else :
object_to_children = current_object
#-----------------------------------------------------------------------
# Here is the recursion step for all the children
for n in node.childNodes :
if n.nodeType == node.ELEMENT_NODE :
_parse_1_1(n, graph, object_to_children, state, incomplete_triples)
# ---------------------------------------------------------------------
# At this point, the parent's incomplete triples may be completed
for (s,p,o) in parent_incomplete_triples :
if s == None and o == None :
# This is an encoded version of a hanging rel for a collection:
incoming_state.add_to_list_mapping( p, current_subject )
else :
if s == None : s = current_subject
if o == None : o = current_subject
graph.add((s,p,o))
# Generate the lists, if any and if this is the level where a new list was originally created
if state.new_list and not state.list_empty() :
for prop in state.get_list_props() :
vals = state.get_list_value(prop)
if vals == None :
# This was an empty list, in fact, ie, the list has been initiated by a <xxx rel="prop" inlist>
# but no list content has ever been added
graph.add( (state.get_list_origin(), prop, ns_rdf["nil"]) )
else :
heads = [ BNode() for r in vals ] + [ ns_rdf["nil"] ]
for i in range(0, len(vals)) :
graph.add( (heads[i], ns_rdf["first"], vals[i]) )
graph.add( (heads[i], ns_rdf["rest"], heads[i+1]) )
# Anchor the list
graph.add( (state.get_list_origin(), prop, heads[0]) )
# -------------------------------------------------------------------
# This should be it...
# -------------------------------------------------------------------
return
##################################################################################################################
def _parse_1_0(node, graph, parent_object, incoming_state, parent_incomplete_triples) :
"""The (recursive) step of handling a single node. See the
U{RDFa 1.0 syntax document<http://www.w3.org/TR/rdfa-syntax>} for further details.
This is the RDFa 1.0 version.
@param node: the DOM node to handle
@param graph: the RDF graph
@type graph: RDFLib's Graph object instance
@param parent_object: the parent's object, as an RDFLib URIRef
@param incoming_state: the inherited state (namespaces, lang, etc.)
@type incoming_state: L{state.ExecutionContext}
@param parent_incomplete_triples: list of hanging triples (the missing resource set to None) to be handled (or not)
by the current node.
@return: whether the caller has to complete it's parent's incomplete triples
@rtype: Boolean
"""
# Update the state. This means, for example, the possible local settings of
# namespaces and lang
state = None
state = ExecutionContext(node, graph, inherited_state=incoming_state)
#---------------------------------------------------------------------------------
# Handling the role attribute is pretty much orthogonal to everything else...
handle_role_attribute(node, graph, state)
#---------------------------------------------------------------------------------
# Handle the special case for embedded RDF, eg, in SVG1.2.
# This may add some triples to the target graph that does not originate from RDFa parsing
# If the function return TRUE, that means that an rdf:RDF has been found. No
# RDFa parsing should be done on that subtree, so we simply return...
if state.options.embedded_rdf and node.nodeType == node.ELEMENT_NODE and handle_embeddedRDF(node, graph, state) :
return
#---------------------------------------------------------------------------------
# calling the host language specific massaging of the DOM
if state.options.host_language in host_dom_transforms and node.nodeType == node.ELEMENT_NODE :
for func in host_dom_transforms[state.options.host_language] : func(node, state)
#---------------------------------------------------------------------------------
# First, let us check whether there is anything to do at all. Ie,
# whether there is any relevant RDFa specific attribute on the element
#
if not has_one_of_attributes(node, "href", "resource", "about", "property", "rel", "rev", "typeof", "src") :
# nop, there is nothing to do here, just go down the tree and return...
for n in node.childNodes :
if n.nodeType == node.ELEMENT_NODE : parse_one_node(n, graph, parent_object, state, parent_incomplete_triples)
return
#-----------------------------------------------------------------
# The goal is to establish the subject and object for local processing
# The behaviour is slightly different depending on the presense or not
# of the @rel/@rev attributes
current_subject = None
current_object = None
prop_object = None
if has_one_of_attributes(node, "rel", "rev") :
# in this case there is the notion of 'left' and 'right' of @rel/@rev
# in establishing the new Subject and the objectResource
current_subject = state.getResource("about","src")
# get_URI may return None in case of an illegal CURIE, so
# we have to be careful here, not use only an 'else'
if current_subject == None :
if node.hasAttribute("typeof") :
current_subject = BNode()
else :
current_subject = parent_object
else :
state.reset_list_mapping(origin = current_subject)
# set the object resource
current_object = state.getResource("resource", "href")
else :
# in this case all the various 'resource' setting attributes
# behave identically, though they also have their own priority
current_subject = state.getResource("about", "src", "resource", "href")
# get_URI_ref may return None in case of an illegal CURIE, so
# we have to be careful here, not use only an 'else'
if current_subject == None :
if node.hasAttribute("typeof") :
current_subject = BNode()
else :
current_subject = parent_object
current_subject = parent_object
else :
state.reset_list_mapping(origin = current_subject)
# in this case no non-literal triples will be generated, so the
# only role of the current_object Resource is to be transferred to
# the children node
current_object = current_subject
# ---------------------------------------------------------------------
## The possible typeof indicates a number of type statements on the new Subject
for defined_type in state.getURI("typeof") :
graph.add((current_subject, ns_rdf["type"], defined_type))
# ---------------------------------------------------------------------
# In case of @rel/@rev, either triples or incomplete triples are generated
# the (possible) incomplete triples are collected, to be forwarded to the children
incomplete_triples = []
for prop in state.getURI("rel") :
if not isinstance(prop,BNode) :
theTriple = (current_subject, prop, current_object)
if current_object != None :
graph.add(theTriple)
else :
incomplete_triples.append(theTriple)
else :
state.options.add_warning(err_no_blank_node % "rel", warning_type=IncorrectBlankNodeUsage, node=node.nodeName)
for prop in state.getURI("rev") :
if not isinstance(prop,BNode) :
theTriple = (current_object,prop,current_subject)
if current_object != None :
graph.add(theTriple)
else :
incomplete_triples.append(theTriple)
else :
state.options.add_warning(err_no_blank_node % "rev", warning_type=IncorrectBlankNodeUsage, node=node.nodeName)
# ----------------------------------------------------------------------
# Generation of the literal values. The newSubject is the subject
# A particularity of property is that it stops the parsing down the DOM tree if an XML Literal is generated,
# because everything down there is part of the generated literal.
if node.hasAttribute("property") :
ProcessProperty(node, graph, current_subject, state).generate_1_0()
# ----------------------------------------------------------------------
# Setting the current object to a bnode is setting up a possible resource
# for the incomplete triples downwards
if current_object == None :
object_to_children = BNode()
else :
object_to_children = current_object
#-----------------------------------------------------------------------
# Here is the recursion step for all the children
for n in node.childNodes :
if n.nodeType == node.ELEMENT_NODE :
_parse_1_0(n, graph, object_to_children, state, incomplete_triples)
# ---------------------------------------------------------------------
# At this point, the parent's incomplete triples may be completed
for (s,p,o) in parent_incomplete_triples :
if s == None and o == None :
# This is an encoded version of a hanging rel for a collection:
incoming_state.add_to_list_mapping( p, current_subject )
else :
if s == None : s = current_subject
if o == None : o = current_subject
graph.add((s,p,o))
# -------------------------------------------------------------------
# This should be it...
# -------------------------------------------------------------------
return
#######################################################################
# Handle the role attribute
[docs]def handle_role_attribute(node, graph, state) :
"""
Handling the role attribute, according to http://www.w3.org/TR/role-attribute/#using-role-in-conjunction-with-rdfa
@param node: the DOM node to handle
@param graph: the RDF graph
@type graph: RDFLib's Graph object instance
@param state: the inherited state (namespaces, lang, etc.)
@type state: L{state.ExecutionContext}
"""
if node.hasAttribute("role") :
if node.hasAttribute("id") :
id = node.getAttribute("id").strip()
subject = URIRef(state.base + '#' + id)
else :
subject = BNode()
predicate = URIRef('http://www.w3.org/1999/xhtml/vocab#role')
for object in state.getURI("role") :
graph.add((subject, predicate, object))
