Add validator for type and whether a field is required

Author: rickychilcott

lib/docx/elements/style.rb

@@ -12,7 +12,14 @@ def self.attributes
         @@attributes
       end
 
-      def self.attribute(name, *selectors, converter: Converters::DefaultValueConverter, validator: Validators::DefaultValidator)
+      def self.required_attributes
+        @@attributes.select { |a| a[:required] }
+      end
+
+      def self.attribute(name, *selectors, required: false, converter: Converters::DefaultValueConverter, validator: Validators::DefaultValidator)
+        @@attributes ||= []
+        @@attributes << {name: name, selectors: selectors, required: required, converter: converter, validator: validator}
+
         define_method(name) do
           selectors
             .lazy
@@ -22,15 +29,27 @@ def self.attribute(name, *selectors, converter: Converters::DefaultValueConverte
         end
 
         define_method("#{name}=") do |value|
-          validator.validate(value) || raise(Errors::StyleInvalidPropertyValue, "Invalid value for #{name}: #{value}")
+          (required && value.nil?) &&
+            raise(Errors::StyleRequiredPropertyValue, "Required value #{name}")
+
+          validator.validate(value) ||
+            raise(Errors::StyleInvalidPropertyValue, "Invalid value for #{name}: '#{value.nil? ? "nil" : value}'")
+
+          encoded_value = converter.encode(value)
 
           selectors.map do |attribute_xpath|
-            encoded_value = converter.encode(value).to_s
             if (existing_attribute = node.at_xpath(attribute_xpath))
-              existing_attribute.value = encoded_value
-              next value
+              if encoded_value.nil?
+                existing_attribute.remove
+              else
+                existing_attribute.value = encoded_value
+              end
+
+              next encoded_value
             end
 
+            next encoded_value if encoded_value.nil?
+
             node_xpath, attribute = attribute_xpath.split("/@")
 
             created_node =
@@ -40,7 +59,8 @@ def self.attribute(name, *selectors, converter: Converters::DefaultValueConverte
                   # find the child node
                   parent_node.at_xpath(child_xpath) ||
                     # or create the child node
-                    Nokogiri::XML::Node.new(child_xpath, parent_node).tap { |created_child_node| parent_node << created_child_node }
+                    Nokogiri::XML::Node.new(child_xpath, parent_node)
+                      .tap { |created_child_node| parent_node << created_child_node }
                 end
 
             created_node.set_attribute(attribute, encoded_value)
@@ -67,9 +87,9 @@ def initialize(configuration, node, **attributes)
 
       attr_accessor :node
 
-      attribute :id, "./@w:styleId"
-      attribute :name, "./w:name/@w:val", "./w:next/@w:val"
-      attribute :type, ".//@w:type"
+      attribute :id, "./@w:styleId", required: true
+      attribute :name, "./w:name/@w:val", "./w:next/@w:val", required: true
+      attribute :type, ".//@w:type", required: true, validator: Validators::ValueValidator.new("paragraph", "character", "table", "numbering")
       attribute :keep_next, "./w:pPr/w:keepNext/@w:val", converter: Converters::BooleanConverter
       attribute :keep_lines, "./w:pPr/w:keepLines/@w:val", converter: Converters::BooleanConverter
       attribute :page_break_before, "./w:pPr/w:pageBreakBefore/@w:val", converter: Converters::BooleanConverter
@@ -112,6 +132,16 @@ def initialize(configuration, node, **attributes)
       attribute :vertical_alignment, "./w:rPr/w:vertAlign/@w:val"
       attribute :lang, "./w:rPr/w:lang/@w:val"
 
+      def valid?
+        self.class.required_attributes.all? do |a|
+          validator = a[:validator]
+          attribute_name = a[:name]
+          attribute_value = self.send(attribute_name)
+
+          validator&.validate(attribute_value)
+        end
+      end
+
       def to_xml
         node.to_xml
       end

lib/docx/elements/style/validators.rb

@@ -15,6 +15,16 @@ def self.validate(value)
             value =~ COLOR_REGEX
           end
         end
+
+        class ValueValidator
+          def initialize(*values)
+            @values = values
+          end
+
+          def validate(value)
+            @values.include?(value)
+          end
+        end
       end
     end
   end

lib/docx/errors.rb

@@ -2,5 +2,6 @@ module Docx
   module Errors
     StyleNotFound = Class.new(StandardError)
     StyleInvalidPropertyValue = Class.new(StandardError)
+    StyleRequiredPropertyValue = Class.new(StandardError)
   end
 end

spec/docx/elements/style_spec.rb

@@ -5,10 +5,8 @@
 
 describe Docx::Elements::Style do
   let(:fixture_path) { Dir.pwd + "/spec/fixtures/partial_styles/full.xml" }
-
-  let(:node) do
-    Nokogiri::XML(File.open(fixture_path)).root.children[1]
-  end
+  let(:fixture_xml) { File.read(fixture_path) }
+  let(:node) { Nokogiri::XML(fixture_xml).root.children[1] }
   let(:style) { described_class.new(double(:configuration), node) }
 
   it "should extract attributes" do
@@ -83,6 +81,14 @@
     expect(node.at_xpath("./w:rPr/w:shd/@w:val").value).to eq("complex")
   end
 
+  it "should allow setting attributes to nil" do
+    style.shading_style = nil
+
+    expect(style.shading_style).to eq(nil)
+    expect(node.at_xpath("./w:pPr/w:shd/@w:val")).to eq(nil)
+    expect { node.at_xpath("./w:pPr/w:shd/@w:val").value }.to raise_error(NoMethodError) # i.e. it's gone!
+  end
+
   describe "#to_xml" do
     it "should return the node as XML" do
       expect(style.to_xml).to eq(node.to_xml)
@@ -99,6 +105,46 @@
     end
   end
 
+  describe "validation" do
+    let(:fixture_path) { Dir.pwd + "/spec/fixtures/partial_styles/basic.xml" }
+
+    it "validation: id" do
+      expect { style.id = nil }.to raise_error(Docx::Errors::StyleRequiredPropertyValue)
+    end
+
+    it "validation: name" do
+      expect { style.name = nil }.to raise_error(Docx::Errors::StyleRequiredPropertyValue)
+    end
+
+    it "validation: type" do
+      expect { style.type = nil }.to raise_error(Docx::Errors::StyleRequiredPropertyValue)
+
+      expect { style.type = "invalid" }.to raise_error(Docx::Errors::StyleInvalidPropertyValue)
+    end
+
+    it "true" do
+      expect(style).to be_valid
+    end
+
+    describe "unhappy" do
+      let(:fixture_xml) do
+        <<~XML
+        <?xml version="1.0" encoding="UTF-8"?>
+        <w:styles xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main" xmlns:w14="http://schemas.microsoft.com/office/word/2010/wordml">
+          <w:style w:type="" w:styleId="">
+            <w:name/>
+          </w:style>
+        </w:styles>
+        XML
+      end
+
+      it "false" do
+        expect(style).to_not be_valid
+      end
+    end
+
+  end
+
   describe "basic" do
     let(:fixture_path) { Dir.pwd + "/spec/fixtures/partial_styles/basic.xml" }