Class: Demolisher::Node

Inherits:
Object
  • Object
show all
Defined in:
lib/demolisher.rb

Overview

Handles all the complexity of accessing the XML contents

Instance Method Summary collapse

Constructor Details

#initialize(xml, namespaces = nil, is_root = true) ⇒ Node

Creates a new Node object.

If the node is not the root node then the secondargument needs to be false.



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# File 'lib/demolisher.rb', line 35

def initialize(xml, namespaces = nil, is_root = true)
  @nodes = [xml]
  @nodes.unshift(nil) unless is_root
  @namespaces = namespaces || {}
  @namespaces.merge!(xml.collect_namespaces) if xml.respond_to?(:collect_namespaces)
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(meth, *args, &block) ⇒ Object

The workhorse, finds the node matching meth.

Rough flow guide:

If a block is given then yield to it each for each instance
  of the element found in the current node.
If no block given then get the first element found
  If the node has only one text element check if the
    method called has a ? suffix then return true if node content
    looks like a boolean. Otherwise return text content
  Otherwise return a new Node instance



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# File 'lib/demolisher.rb', line 72

def method_missing(meth, *args, &block) # :nodoc:
  xpath = _xpath_for_element(meth.to_s, args.shift)
  return nil if xpath.empty?

  if block_given?
    xpath.each_with_index do |node, idx|
      @nodes.push(node)
      case block.arity
      when 1
        yield idx
      when 2
        yield self.class.new(node, @namespaces, false), idx
      else
        yield
      end
      @nodes.pop
    end
    self
  else
    node = xpath.first

    if node.xpath('text()').length == 1
      content = node.xpath('text()').first.content
      case meth.to_s
      when /\?$/
        !! Regexp.new(/(t(rue)?|y(es)?|1)/i).match(content)
      else
        content
      end
    else
      self.class.new(node, @namespaces, false)
    end
  end
end

Instance Method Details

#[](attr_name) ⇒ Object

Access an attribute of the current node.

XML file:

<addressbook>
  <person rel="friend">
    <firstname>Steve</firstname>
  </person>
</addressbook>

Example:

xml.addressbook do
  xml.person do
    puts "#{xml.firstname} is a #{xml['rel']}"  #=> "Steve is a friend"
  end
end



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# File 'lib/demolisher.rb', line 58

def [](attr_name)
  _current_node.attributes[attr_name].to_s
end

#_current_node ⇒ Object 



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# File 'lib/demolisher.rb', line 115

def _current_node
  @nodes.last
end

#_element_from_symbol(el_or_ns, el_for_ns = nil) ⇒ Object

Transforms a symbol into a XML element path.



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# File 'lib/demolisher.rb', line 124

def _element_from_symbol(el_or_ns,el_for_ns = nil) # :nodoc:
  "#{_is_root_node? ? '/' : nil}#{el_or_ns.gsub(/[^a-z0-9_-]/i, '')}#{el_for_ns && el_for_ns.inspect}"
end

#_is_root_node? ⇒ Boolean

Indicates if the current node is the root of the XML document.

Returns:

  • (Boolean) 


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# File 'lib/demolisher.rb', line 129

def _is_root_node?
  @nodes.size == 1
end

#_xpath_for_element(el_or_ns, el_for_ns = nil) ⇒ Object 



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# File 'lib/demolisher.rb', line 119

def _xpath_for_element(el_or_ns, el_for_ns = nil)
  _current_node.xpath(_element_from_symbol(el_or_ns, el_for_ns), @namespaces)
end

#inspect ⇒ Object

:nodoc:



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# File 'lib/demolisher.rb', line 111

def inspect # :nodoc:
  "#<#{self.class} node=#{_current_node.name}>"
end

#to_s ⇒ Object

Returns the current nodes contents.



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# File 'lib/demolisher.rb', line 108

def to_s # :nodoc:
  _current_node.content.strip
end