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A small nokogiri xml reader DSL.
# A small DSL for helping parsing documents using Nokogiri::XML::Reader. The
# XML Reader is a good way to move a cursor through a (large) XML document fast,
# but is not as cumbersome as writing a full SAX document handler. Read about
# it here: http://nokogiri.org/Nokogiri/XML/Reader.html
#
# Just pass the reader in this parser and specificy the nodes that you are interested
# in in a block. You can just parse every node or only look inside certain nodes.
#
# A small example:
#
# Xml::Parser.new(Nokogiri::XML::Reader(open(file))) do
# inside_element 'User' do
# for_element 'Name' do puts "Username: #{inner_xml}" end
# for_element 'Email' do puts "Email: #{inner_xml}" end
#
# for_element 'Address' do
# puts 'Start of address:'
# inside_element do
# for_element 'Street' do puts "Street: #{inner_xml}" end
# for_element 'Zipcode' do puts "Zipcode: #{inner_xml}" end
# for_element 'City' do puts "City: #{inner_xml}" end
# end
# puts 'End of address'
# end
# end
# end
#
# It does NOT fail on missing tags, and does not guarantee order of execution. It parses
# every tag regardless of nesting. The only way to guarantee scope is by using
# the `inside_element` method. This limits the parsing to the current or the named tag.
# If tags are encountered multiple times, their blocks will be called multiple times.
require 'nokogiri'
module Xml
class Parser
def initialize(node, &block)
@node = node
@node.each do
self.instance_eval &block
end
end
def name
@node.name
end
def inner_xml
@node.inner_xml.strip
end
def is_start?
@node.node_type == Nokogiri::XML::Reader::TYPE_ELEMENT
end
def is_end?
@node.node_type == Nokogiri::XML::Reader::TYPE_END_ELEMENT
end
def attribute(attribute)
@node.attribute(attribute)
end
def for_element(name, &block)
return unless self.name == name and is_start?
self.instance_eval &block
end
def inside_element(name=nil, &block)
return unless name.nil? or (self.name == name and is_start?)
name = @node.name
depth = @node.depth
@node.each do
return if self.name == name and is_end? and @node.depth == depth
self.instance_eval &block
end
end
end
end
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