enhancements for Onix 3 support

README.md

@@ -13,6 +13,19 @@ pp message.products.first.identifiers.first
 
 Ruby elements variables are underscored, lowercase of ONIX tags (Product -> product, DescriptiveDetail -> descriptive_detail) and pluralized in case of array (ProductSupply -> product_supplies).
 
+#### Using reader
+
+Able to optionally stream each product rather than read the full ONIX file at once. This can be helpful for large ONIX files.
+
+nb. The version will need to be explicitly, and each `product` is yielded exactly once. For more info on this pattern see [Nokogiri::XML::Reader](https://nokogiri.org/rdoc/Nokogiri/XML/Reader.html)
+
+```ruby
+onix_message = ONIX::ONIXMessage.new
+onix_message.set_release_from_xml({}, '3.0')
+onix_message.reader("onix_file.xml")
+onix_message.each { |product| ...handle product... }
+```
+
 ### High level API
 High level methods give abstracted and simplified access to the most important data.  
 See https://www.rubydoc.info/gems/im_onix/ONIX/Product for high level API rdoc and onix_pp.rb, onix3_to_onix2.rb and onix3_to_onix3.rb sample in bin/

lib/onix/contributor.rb

@@ -6,7 +6,7 @@
 module ONIX
   class Contributor < SubsetDSL
     element "SequenceNumber", :integer, :cardinality => 0..1
-    element "ContributorRole", :subset, :shortcut => :role, :cardinality => 1..n
+    elements "ContributorRole", :subset, :shortcut => :roles, :cardinality => 1..n
     elements "FromLanguage", :subset, :klass => "LanguageCode", :cardinality => 0..n
     elements "ToLanguage", :subset, :klass => "LanguageCode", :cardinality => 0..n
 
@@ -50,6 +50,11 @@ def place
       self.places.first
     end
 
+    # @return [ContributorRole]
+    def role
+      self.roles.first
+    end
+
     # !@endgroup
 
     # @!group High level

lib/onix/onix_message.rb

@@ -104,6 +104,19 @@ def open(arg, force_encoding = nil)
       xml
     end
 
+    def reader(file_path)
+      @reader = Nokogiri::XML::Reader(File.open(file_path, 'r'))
+    end
+
+    def each(&block)
+      @reader.each do |node|
+        if @reader.node_type == 1 && @reader.name == "Product"
+          element = Nokogiri::XML(@reader.outer_xml).at('Product')
+          yield self.product_klass.parse(element)
+        end
+      end
+    end
+
     # release as an integer eg: 210, 300, 301
     # @return [Number]
     def version
@@ -125,13 +138,15 @@ def detect_release(element)
     end
 
     def set_release_from_xml(node, force_release)
+      if force_release
+        @release = force_release.to_s
+        return
+      end
+
       @release = node["release"]
       unless @release
         @release = detect_release(node)
       end
-      if force_release
-        @release = force_release.to_s
-      end
     end
 
     def product_klass

lib/onix/subset.rb

@@ -1,5 +1,6 @@
 require 'forwardable'
 require 'cgi'
+require 'delegate'
 
 module ONIX
   class ShortToRef
@@ -492,4 +493,4 @@ def parse(n)
       end
     end
   end
-end
+end