Module: HappyMapper

Defined in:
lib/happymapper.rb,
lib/happymapper/item.rb,
lib/happymapper/element.rb,
lib/happymapper/attribute.rb,
lib/happymapper/text_node.rb

Defined Under Namespace

Modules: ClassMethods Classes: AnonymousWrapperClassFactory, Attribute, Element, Item, TextNode

Constant Summary collapse

VERSION = 
"0.5.4"
DEFAULT_NS = 
"happymapper"

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/happymapper.rb', line 14

def self.included(base)
  base.instance_variable_set("@attributes", {})
  base.instance_variable_set("@elements", {})
  base.instance_variable_set("@registered_namespaces", {})
  base.instance_variable_set("@wrapper_anonymous_classes", {})

  base.extend ClassMethods
end

Instance Method Details

#parse(xml, options = {}) ⇒ Object

Parse the xml and update this instance. This does not update instances of HappyMappers that are children of this object. New instances will be created for any HappyMapper children of this object.

Params and return are the same as the class parse() method above.



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# File 'lib/happymapper.rb', line 665

def parse(xml, options = {})
  self.class.parse(xml, options.merge!(:update => self))
end

#to_xml(builder = nil, default_namespace = nil, tag_from_parent = nil) ⇒ String, Nokogiri::XML::Builder

Create an xml representation of the specified class based on defined HappyMapper elements and attributes. The method is defined in a way that it can be called recursively by classes that are also HappyMapper classes, allowg for the composition of classes.

Parameters:

  • builder (Nokogiri::XML::Builder) (defaults to: nil) —

    an instance of the XML builder which is being used when called recursively.

  • default_namespace (String) (defaults to: nil) —

    the name of the namespace which is the default for the xml being produced; this is specified by the element declaration when calling #to_xml recursively.

  • tag_from_parent (String) (defaults to: nil) —

    the xml tag to use on the element when being called recursively. This lets the parent doc define its own structure. Otherwise the element uses the tag it has defined for itself. Should only apply when calling a child HappyMapper element.

Returns:

  • (String, Nokogiri::XML::Builder) —

    return XML representation of the HappyMapper object; when called recursively this is going to return and Nokogiri::XML::Builder object.



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# File 'lib/happymapper.rb', line 437

def to_xml(builder = nil,default_namespace = nil,tag_from_parent = nil)
  
  #
  # If to_xml has been called without a passed in builder instance that
  # means we are going to return xml output. When it has been called with
  # a builder instance that means we most likely being called recursively
  # and will return the end product as a builder instance. 
  #
  unless builder
    write_out_to_xml = true
    builder = Nokogiri::XML::Builder.new
  end
  
  #
  # Find the attributes for the class and collect them into an array
  # that will be placed into a Hash structure
  #
  attributes = self.class.attributes.collect do |attribute|
    
    #
    # If an attribute is marked as read_only then we want to ignore the attribute
    # when it comes to saving the xml document; so we wiill not go into any of
    # the below process
    # 
    unless attribute.options[:read_only]
    
      value = send(attribute.method_name)
    
      #
      # If the attribute defines an on_save lambda/proc or value that maps to 
      # a method that the class has defined, then call it with the value as a
      # parameter.
      #
      if on_save_action = attribute.options[:on_save]
        if on_save_action.is_a?(Proc)
          value = on_save_action.call(value)
        elsif respond_to?(on_save_action)
          value = send(on_save_action,value)
        end
      end
    
      #
      # Attributes that have a nil value should be ignored unless they explicitly
      # state that they should be expressed in the output.
      #
      if value || attribute.options[:state_when_nil]
        attribute_namespace = attribute.options[:namespace] || default_namespace
        [ "#{attribute_namespace ? "#{attribute_namespace}:" : ""}#{attribute.tag}", value ]
      else
        []
      end
      
    else
      []
    end
    
  end.flatten
  
  attributes = Hash[ *attributes ]
                    
  #
  # Create a tag in the builder that matches the class's tag name unless a tag was passed
  # in a recursive call from the parent doc.  Then append
  # any attributes to the element that were defined above.
  #
  builder.send("#{tag_from_parent || self.class.tag_name}_",attributes) do |xml|
    
    #
    # Add all the registered namespaces to the root element.
    # When this is called recurisvely by composed classes the namespaces
    # are still added to the root element
    # 
    # However, we do not want to add the namespace if the namespace is 'xmlns'
    # which means that it is the default namesapce of the code.
    #
    if self.class.instance_variable_get('@registered_namespaces') && builder.doc.root
      self.class.instance_variable_get('@registered_namespaces').each_pair do |name,href|
        name = nil if name == "xmlns"
        builder.doc.root.add_namespace(name,href)
      end
    end
    
    #
    # If the object we are persisting has a namespace declaration we will want
    # to use that namespace or we will use the default namespace.
    # When neither are specifed we are simply using whatever is default to the
    # builder
    #
    if self.class.respond_to?(:namespace) && self.class.namespace
      xml.parent.namespace = builder.doc.root.namespace_definitions.find { |x| x.prefix == self.class.namespace }
    elsif default_namespace
      xml.parent.namespace = builder.doc.root.namespace_definitions.find { |x| x.prefix == default_namespace }
    end

    
    #
    # When a content has been defined we add the resulting value
    # the output xml
    #
    if content = self.class.instance_variable_get('@content')
      
      unless content.options[:read_only]
        text_accessor = content.tag || content.name
        value = send(text_accessor)
      
        if on_save_action = content.options[:on_save]
          if on_save_action.is_a?(Proc)
            value = on_save_action.call(value)
          elsif respond_to?(on_save_action)
            value = send(on_save_action,value)
          end
        end
      
        builder.text(value)
      end
      
    end

    #
    # for every define element (i.e. has_one, has_many, element) we are
    # going to persist each one
    #
    self.class.elements.each do |element|
      
      #
      # If an element is marked as read only do not consider at all when 
      # saving to XML.
      # 
      unless element.options[:read_only]
        
        tag = element.tag || element.name
        
        #
        # The value to store is the result of the method call to the element,
        # by default this is simply utilizing the attr_accessor defined. However,
        # this allows for this method to be overridden
        #
        value = send(element.name)

        #
        # If the element defines an on_save lambda/proc then we will call that
        # operation on the specified value. This allows for operations to be 
        # performed to convert the value to a specific value to be saved to the xml.
        #
        if on_save_action = element.options[:on_save]
          if on_save_action.is_a?(Proc)
            value = on_save_action.call(value)
          elsif respond_to?(on_save_action)
            value = send(on_save_action,value)
          end 
        end

        #
        # Normally a nil value would be ignored, however if specified then
        # an empty element will be written to the xml
        #
        if value.nil? && element.options[:single] && element.options[:state_when_nil]
          xml.send("#{tag}_","")
        end
      
        #
        # To allow for us to treat both groups of items and singular items
        # equally we wrap the value and treat it as an array.
        #
        if value.nil?
          values = []
        elsif value.respond_to?(:to_ary) && !element.options[:single]
          values = value.to_ary
        else
          values = [value]
        end
      
        values.each do |item|

          if item.is_a?(HappyMapper)

            #
            # Other items are convertable to xml through the xml builder
            # process should have their contents retrieved and attached
            # to the builder structure
            #
            item.to_xml(xml,element.options[:namespace],element.options[:tag] || nil)

          elsif item
          
            item_namespace = element.options[:namespace] || self.class.namespace || default_namespace 
          
            #
            # When a value exists we should append the value for the tag
            #
            if item_namespace
              xml[item_namespace].send("#{tag}_",item.to_s)
            else
              xml.send("#{tag}_",item.to_s)
            end

          else

            #
            # Normally a nil value would be ignored, however if specified then
            # an empty element will be written to the xml
            #
            xml.send("#{tag}_","") if element.options[:state_when_nil]

          end

        end
        
      end
    end

  end

  # Write out to XML, this value was set above, based on whether or not an XML
  # builder object was passed to it as a parameter. When there was no parameter
  # we assume we are at the root level of the #to_xml call and want the actual
  # xml generated from the object. If an XML builder instance was specified 
  # then we assume that has been called recursively to generate a larger 
  # XML document.
  write_out_to_xml ? builder.to_xml : builder
  
end