Class: Reddy::RdfXmlParser

Inherits:
Parser
  • Object
show all
Defined in:
lib/reddy/rdfxmlparser.rb

Defined Under Namespace

Classes: EvaluationContext

Constant Summary collapse

CORE_SYNTAX_TERMS = 
%w(RDF ID about parseType resource nodeID datatype).map {|n| "http://www.w3.org/1999/02/22-rdf-syntax-ns##{n}"}
OLD_TERMS = 
%w(aboutEach aboutEachPrefix bagID).map {|n| "http://www.w3.org/1999/02/22-rdf-syntax-ns##{n}"}

Instance Attribute Summary

Attributes inherited from Parser

#debug, #doc, #graph

Instance Method Summary collapse

Methods inherited from Parser

#initialize, n3_parser, parse, rdfa_parser, rdfxml_parser

Constructor Details

This class inherits a constructor from Reddy::Parser

Instance Method Details

#parse(stream, uri = nil, options = {}, &block) ⇒ Graph

Parse RDF/XML document from a string or input stream to closure or graph.

Optionally, the stream may be a string or Nokogiri::XML::Document With a block, yeilds each statement with URIRef, BNode or Literal elements

options[:debug]

Array to place debug messages

options[:strict]

Raise Error if true, continue with lax parsing, otherwise

Parameters:

  • stream:: (IO) —

    the RDF/XML IO stream, string or Nokogiri::XML::Document

  • uri:: (String) —

    the URI of the document

  • options:: (Hash) —

    Parser options, one of

Returns:

  • (Graph) —

    Returns the graph containing parsed triples

Raises:

  • (Error) —

    Raises RdfError if strict

Author:

  • Gregg Kellogg



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# File 'lib/reddy/rdfxmlparser.rb', line 113

def parse(stream, uri = nil, options = {}, &block) # :yields: triple
  super

  @doc = case stream
  when Nokogiri::XML::Document then stream
  else   Nokogiri::XML.parse(stream, uri)
  end
  
  @id_mapping = Hash.new

  raise ParserException, "Empty document" if @doc.nil? && @strict
  @callback = block
  
  root = @doc.root
  
  # Look for rdf:RDF elements and process each.
  rdf_nodes = root.xpath("//rdf:RDF", RDF_NS.prefix => RDF_NS.uri.to_s)
  if rdf_nodes.length == 0
    # If none found, root element may be processed as an RDF Node

    ec = EvaluationContext.new(@uri, root, @graph)
    nodeElement(root, ec)
  else
    rdf_nodes.each do |node|
      # XXX Skip this element if it's contained within another rdf:RDF element
      
      # Extract base, lang and namespaces from parents to create proper evaluation context
      ec = EvaluationContext.new(@uri, nil, @graph)
      ec.extract_from_ancestors(node)
      node.children.each {|el|
        next unless el.elem?
        new_ec = ec.clone(el)
        nodeElement(el, new_ec)
      }
    end
  end

  @graph
end