Module: SimpleXML::Simplifyer

Included in:
REXML::Element
Defined in:
lib/simple_xml/simplifyer.rb

Overview

Extension to the element class of rexml to make working with simple xml documents more easy and intuitive. Therefor it uses the combination of hashes and the rexml XPath implementation.

Examples:

Usage with a simple document

doc = REXML::Document.new(%Q{
  <?xml version="1.0"?>
  <address>
    <country iso_code="de" nationality="deutsch">Deutschland</country>
    <zip_code>76135</zip_code>
    <city>Karlsruhe</city>
    <street>
      <name_and_number>Ernst-Frey-Str. 10</name_and_number>
    </street>
  </address>
}
doc.simplify("/address") #=> { :country => "Deutschland", :zip_code => "76135", :city => "Karlsruhe", :street => { :name_and_number => "Ernst-Frey-Str. 10" } }
doc.simplify_attributes("/address/country") #=> { :iso_code => "de", :nationality => "deutsch" }

Instance Method Summary collapse

Instance Method Details

#simplify(xpath = nil) ⇒ Hash, NilClass

Simplifies the current element or an xpath to a subelement to a hash.

Parameters:

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

    an optional xpath for an element to convert

Returns:

  • (Hash, NilClass) —

    nil if the xpath didn’t match to a node or a hash otherwise. If elements have the same name they will be merged into an array.



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# File 'lib/simple_xml/simplifyer.rb', line 25

def simplify(xpath = nil)
  if xpath
    if element = REXML::XPath.first(self, xpath)
      element.simplify
    else
      nil
    end
  else
    # just convert the elements if there are some
    if contains_no_text_elements?
      tree = {} # the subtree
      last_name = nil # helper for detecting duplicate element names
      self.each do |element|
        # we ignore all text elements that are in between the elements
        if element.is_a? REXML::Element
          name = element.name.to_sym
          if last_name == name
            # create an array if there is more than one element with
            # the same name
            tree[name] = [tree[name]] unless tree[name].is_a?(Array)
            tree[name] += [element.simplify]
          else
            # create a simple element (key - value) in the hash
            tree[name] = element.simplify
            last_name = name
          end
        end
      end
      tree
    else
      # if there is just text left the text elements will be used
      self.text
    end
  end
end

#simplify_attributes(xpath = nil) ⇒ Hash, NilClass

Simplifies the current element attributes or an xpath to subelement attributes to a hash.

Parameters:

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

    an optional xpath for an element to convert

Returns:

  • (Hash, NilClass) —

    nil if the xpath didn’t match to a node or a hash otherwise.



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# File 'lib/simple_xml/simplifyer.rb', line 65

def simplify_attributes(xpath = nil)
  if xpath
    if element = REXML::XPath.first(self, xpath)
      element.simplify_attributes
    else
      nil
    end
  else
    hash = {}
    attributes.each { |key, value| hash[key.to_sym] = value }
    hash
  end    
end