Getting Started¶

Requiring the Library¶

There are several ways to load libxml-ruby:

# Recommended - keeps everything under the LibXML namespace
require 'libxml-ruby'
document = LibXML::XML::Document.new

# Convenience - mixes LibXML into the global namespace
require 'xml'
document = XML::Document.new

# In your own namespace
require 'libxml-ruby'

module MyApp
  include LibXML

  class Processor
    def parse(file)
      XML::Document.file(file)
    end
  end
end

Choosing a Parser¶

libxml-ruby provides four parsers, each suited to different use cases:

Parser	Best For
`XML::Parser`	General-purpose DOM parsing. Loads the entire document into a tree.
`XML::Reader`	Large documents that don't fit in memory. Pull-based streaming API.
`XML::HTMLParser`	Parsing HTML documents (tolerates malformed markup).
`XML::SaxParser`	Event-driven parsing with callbacks.

Data Sources¶

All parsers support multiple data sources:

# From a file
doc = XML::Parser.file('data.xml').parse

# From a string
doc = XML::Parser.string('<root/>').parse

# From an IO object
File.open('data.xml') do |io|
  doc = XML::Parser.io(io).parse
end

A Complete Example¶

require 'libxml-ruby'

# Parse
doc = LibXML::XML::Document.file('books.xml')

# Navigate
root = doc.root
puts root.name

# Find nodes with XPath
doc.find('//book[@year > 2000]').each do |book|
  title = book.find_first('title').content
  puts title
end

# Create new content
new_book = LibXML::XML::Node.new('book')
new_book['year'] = '2024'
new_book << LibXML::XML::Node.new('title', 'New Book')
root << new_book

# Save
doc.save('books_updated.xml', indent: true)