WIP Patch DFC connector to fix SKOS Concept parsing

This is to let us use intermediary SKOS Concept.
Upstream PR for more details: https://github.com/datafoodconsortium/connector-codegen/pull/10/files

engines/dfc_provider/lib/data_food_consortium/connector/connector.rb

@@ -6,6 +6,9 @@ require "datafoodconsortium/connector"
 # Then our tools for monky-patching:
 require_relative "importer"
 require_relative "context"
+require_relative "skos_parser_element"
+require_relative "skos_concept"
+require_relative "skos_parser"
 
 module DataFoodConsortium
   module Connector

engines/dfc_provider/lib/data_food_consortium/connector/skos_concept.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require_relative 'skos_helper'
+
+module DataFoodConsortium
+  module Connector
+    class SKOSConcept
+	    include DataFoodConsortium::Connector::SKOSHelper
+    end
+  end
+end

engines/dfc_provider/lib/data_food_consortium/connector/skos_helper.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module DataFoodConsortium::Connector::SKOSHelper
+  def addAttribute(name, value)
+    self.instance_variable_set("@#{name}", value)
+    self.define_singleton_method(name) do
+      instance_variable_get("@#{name}")
+    end
+  end
+
+  def hasAttribute(name)
+    self.methods.include?(:"#{name}")
+  end
+end

engines/dfc_provider/lib/data_food_consortium/connector/skos_parser.rb

@@ -1,11 +1,75 @@
 # frozen_string_literal: true
 
+require_relative 'skos_helper'
+
+module DataFoodConsortium
+  module Connector
+    class SKOSInstance
+      include DataFoodConsortium::Connector::SKOSHelper
+
+      # Return a list of singelton methods, ie the list of Concept available
+      def topConcepts
+        self.methods(false).sort
+      end
+    end
+  end
+end
+
 # Overriding the current implementation to store all parsed concepts for
 # lookup later. Otherwise the importer can't associate these.
 # This is just a workaround and needs to be solved upstream.
 module DataFoodConsortium
   module Connector
     class SKOSParser
+      CONCEPT_SCHEMES = ["Facet", "productTypes"].freeze
+
+      def initialize
+        @results = DataFoodConsortium::Connector::SKOSInstance.new
+        @skosConcepts = {}
+        @rootElements = []
+        @broaders = {}
+        # Flag used to tell the parser to use SkosConcept object when parsing data from Concept Scheme
+        # defined in CONCEPT_SCHEMES
+        @useSkosConcept = false
+      end
+
+      def parse(data)
+        init
+
+        data.each do |element|
+          current = DataFoodConsortium::Connector::SKOSParserElement.new(element)
+
+          setSkosConceptFlag(current)
+
+          if current.isConcept? || current.isCollection?
+            if !@skosConcepts.has_key?(current.id)
+              concept = createSKOSConcept(current)
+              @skosConcepts[current.id] = concept
+            end
+
+            if current.hasBroader
+              current.broader.each do |broaderId|
+                if !@broaders.has_key?(broaderId)
+                  @broaders[broaderId] = []
+                end
+
+                @broaders[broaderId].push(current.id)
+              end
+            # No broader, save the concept to the root
+            else
+              @rootElements.push(current.id)
+            end
+          end
+        end
+
+        @rootElements.each do |rootElementId|
+          setResults(@results, rootElementId)
+        end
+
+        @results
+      end
+
+      # TODO check if this is still needed
       def self.concepts
         @concepts ||= {}
       end
@@ -13,10 +77,59 @@ module DataFoodConsortium
       protected
 
       def createSKOSConcept(element) # rubocop:disable Naming/MethodName
-        concept = DataFoodConsortium::Connector::SKOSConcept.new(element.id)
-        concept.semanticType = element.type
-        self.class.concepts[element.id] = concept
-        concept
+        skosConcept = DataFoodConsortium::Connector::SKOSConcept.new(
+          element.id, broaders: element.broader, narrowers: element.narrower
+        )
+        skosConcept.semanticType = element.type
+        # TODO check if this is still needed
+        # original patch by Maikel
+        self.class.concepts[element.id] = skosConcept
+
+        skosConcept
+      end
+
+      private
+
+      def init
+        @results = DataFoodConsortium::Connector::SKOSInstance.new
+        @skosConcepts = {}
+        @rootElements = []
+        @broaders = {}
+        @useSkosConcept = false
+      end
+
+      def setResults(parent, id)
+        name = getValueWithoutPrefix(id)
+
+        if !parent.hasAttribute(name)
+          if @useSkosConcept && !@skosConcepts[id].nil?
+            parent.addAttribute(name, @skosConcepts[id])
+          else
+            parent.addAttribute(name, DataFoodConsortium::Connector::SKOSInstance.new)
+          end
+        end
+
+        # Leaf concepts, stop the process
+        if !@broaders.has_key?(id)
+          parent.instance_variable_set("@#{name}", @skosConcepts[id])
+          return
+        end
+
+        @broaders[id].each do |narrower|
+          parentSkosInstance = parent.instance_variable_get("@#{name}")
+
+          setResults(parentSkosInstance, narrower) # recursive call
+        end
+      end
+
+      def setSkosConceptFlag(current)
+        @useSkosConcept = true if current.isConceptScheme? && matchingConceptSchemes(current)
+      end
+
+      def matchingConceptSchemes(current)
+        regex = /#{CONCEPT_SCHEMES.join("|")}/
+
+        current.id =~ regex
       end
     end
   end

engines/dfc_provider/lib/data_food_consortium/connector/skos_parser_element.rb

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module DataFoodConsortium
+  module Connector
+    class SKOSParserElement
+      attr_reader :narrower
+
+      def initialize(element)
+        @broader = []
+        @narrower = []
+
+        if element
+          @id = element["@id"]
+
+          if element["http://www.w3.org/1999/02/22-rdf-syntax-ns#type"]
+            @type = extractId(element["http://www.w3.org/1999/02/22-rdf-syntax-ns#type"])
+          elsif element["@type"]
+            @type = extractId(element["@type"])
+          else
+            @type = "undefined"
+          end
+
+          if element["http://www.w3.org/2004/02/skos/core#broader"]
+            element["http://www.w3.org/2004/02/skos/core#broader"].each do |broader|
+              @broader.push(broader["@id"])
+            end
+          end
+
+          if element["http://www.w3.org/2004/02/skos/core#narrower"]
+            element["http://www.w3.org/2004/02/skos/core#narrower"].each do |narrower|
+              @narrower.push(narrower["@id"])
+            end
+          end
+        else
+          @id = ""
+          @type = ""
+        end
+      end
+
+      def isConceptScheme?
+        @type == "http://www.w3.org/2004/02/skos/core#ConceptScheme"
+      end
+    end
+  end
+end