Class: Marc2LinkedData::Resource

Inherits:
Object
  • Object
show all
Defined in:
lib/marc2linkeddata/resource.rb

Direct Known Subclasses

Isni, LibAuth, Loc, OclcIdentity, OclcResource, Viaf

Constant Summary collapse

@@config =

attr_reader :config

nil

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(uri = nil) ⇒ Resource

Returns a new instance of Resource.



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# File 'lib/marc2linkeddata/resource.rb', line 11

def initialize(uri=nil)
  @@config ||= Marc2LinkedData.configuration
  if uri =~ /\A#{URI::regexp}\z/
    uri = Addressable::URI.parse(uri.to_s) rescue nil
  end
  # Strip off any trailing '/'
  if uri.to_s.end_with? '/'
    uri = uri.to_s.gsub(/\/$/,'')
    uri = Addressable::URI.parse(uri.to_s) rescue nil
  end
  raise 'invalid uri' unless uri.instance_of? Addressable::URI
  @iri = uri
end

Instance Attribute Details

#iri ⇒ Object

Returns the value of attribute iri.



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# File 'lib/marc2linkeddata/resource.rb', line 6

def iri
  @iri
end

Instance Method Details

#get_rdf(uri4rdf) ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 40

def get_rdf(uri4rdf)
  tries = 0
  begin
    tries += 1
    @rdf = RDF::Graph.load(uri4rdf)
  rescue
    retry if tries <= 2
    binding.pry if @@config.debug
    nil
  end
end

#id ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 25

def id
  @iri.basename
end

#iri_types ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 60

def iri_types
  q = SPARQL.parse("SELECT * WHERE { <#{@iri}> a ?o }")
  rdf.query(q)
end

#rdf ⇒ Object

This method is often overloaded in subclasses because RDF services use variations in the URL ‘extension’ patterns; e.g. see Loc#rdf and Viaf#rdf



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# File 'lib/marc2linkeddata/resource.rb', line 32

def rdf
  return @rdf unless @rdf.nil?
  # TODO: try to retrieve the rdf from a local triple store
  # TODO: if local triple store fails, try remote source(s)
  # TODO: if retrieved from a remote source, save the rdf to a local triple store
  @rdf = get_rdf(@iri.to_s)
end

#rdf_find_object(id) ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 65

def rdf_find_object(id)
  # TODO: convert this to an RDF.rb graph query?
  return nil unless rdf_valid?
  rdf.each_statement do |s|
    if s.subject == @iri.to_s
      return s.object if s.object.to_s =~ Regexp.new(id, Regexp::IGNORECASE)
    end
  end
  nil
end

#rdf_find_subject(id) ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 76

def rdf_find_subject(id)
  # TODO: convert this to an RDF.rb graph query?
  return nil unless rdf_valid?
  rdf.each_statement do |s|
    return s.subject if s.subject.to_s =~ Regexp.new(id, Regexp::IGNORECASE)
  end
  nil
end

#rdf_uri ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 52

def rdf_uri
  RDF::URI.new(@iri)
end

#rdf_valid? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/marc2linkeddata/resource.rb', line 56

def rdf_valid?
  iri_types.length > 0
end

#resolve_external_auth(url) ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 85

def resolve_external_auth(url)
  begin
    # RestClient does all the response code handling and redirection.
    url = Marc2LinkedData.http_head_request(url)
    if url.nil?
      @@config.logger.warn "#{@iri}\t// #{url}"
    else
      @@config.logger.debug "Mapped #{@iri}\t-> #{url}"
    end
  rescue
    binding.pry if @@config.debug
    @@config.logger.error "unknown http error for #{@iri}"
    url = nil
  end
  url
end

#same_as ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 102

def same_as
  same_as_url = 'http://sameas.org/rdf?uri=' + URI.encode(@iri.to_s)
  RDF::Graph.load(same_as_url)
end

#same_as_array ⇒ Object 



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# File 'lib/marc2linkeddata/resource.rb', line 107

def same_as_array
  q = SPARQL.parse("SELECT * WHERE { <#{@iri}> <http://www.w3.org/2002/07/owl#sameAs> ?o }")
  same_as.query(q).collect {|s| s[:o] }
end