Module: RoadForest::Graph::Etagging

Included in:
Interface::RDF
Defined in:
lib/roadforest/graph/etagging.rb

Instance Method Summary collapse

Instance Method Details

#blank_mapped(quads) ⇒ Object 



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# File 'lib/roadforest/graph/etagging.rb', line 18

def blank_mapped(quads)
  sequence = 0
  mapping = Hash.new do |h,k|
    h[k] = RDF::Node.new(sequence+=1)
  end

  quads.map do |quad|
    quad.map do |term|
      case term
      when RDF::Node
        mapping[term].to_s
      when nil
        nil
      else
        term.to_s
      end
    end
  end
end

#etag_from(graph) ⇒ Object 



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# File 'lib/roadforest/graph/etagging.rb', line 5

def etag_from(graph)
  require 'openssl'
  quads = sorted_quads(graph)
  mapped = blank_mapped(quads)
  strings = mapped.map(&:inspect)

  ripe = OpenSSL::Digest::RIPEMD160.new
  mapped.each do |quad|
    ripe << quad.inspect
  end
  "W/\"#{ripe.base64digest}\""
end

#sorted_quads(graph) ⇒ Object 



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# File 'lib/roadforest/graph/etagging.rb', line 38

def sorted_quads(graph)
  graph.statements.map do |statement|
    [statement.subject, statement.predicate, statement.object, statement.context]
  end.sort_by do |quad|
    quad.map do |term|
      case term
      when RDF::Node
        nil
      else
        term
      end
    end.join("/")
  end
end