Saxy

Memory-efficient XML parser. Finds object definitions in XML and translates them into Ruby objects.

It uses SAX parser under the hood, which means that it doesn't load the whole XML file into memory. It goes once though it and yields objects along the way.

Installation

Add this line to your application's Gemfile:

gem 'saxy'

And then execute:

$ bundle

Or install it yourself as:

$ gem install saxy

Usage

Assume the XML file:

<?xml version='1.0' encoding='UTF-8'?>
<webstore>
  <name>Amazon</name>
  <products>
    <product>
      <name>Kindle - The world's best-selling e-reader.</name>
      <images>
        <thumbSize width="80" height="60">http://amazon.com/kindle_thumb.jpg</thumbSize>
      </images>
    </product>
    <product>
      <name>Kindle Touch - Simple-to-use touchscreen with built-in WIFI.</name>
      <images>
        <thumbSize width="120" height="90">http://amazon.com/kindle_touch_thumb.jpg</thumbSize>
      </images>
    </product>
  </products>
</webstore>

You instantiate the parser by passing path to XML file and object-identyfing tag name as its arguments.

The following will parse the XML, find product definitions (inside <product> and </product> tags), build OpenStructs and yield them inside the block. Tag attributes become object attributes and attributes' name are underscored.

Saxy.parse("filename.xml", "product").each do |product|
  puts product.name
  puts product.images.thumb_size.contents
  puts "#{product.images.thumb_size.width}x#{product.images.thumb_size.height}"
end

# =>
  Kindle - The world's best-selling e-reader.
  http://amazon.com/kindle_thumb.jpg
  80x60
  Kindle Touch - Simple-to-use touchscreen with built-in WIFI.
  http://amazon.com/kindle_touch_thumb.jpg
  120x90

Saxy supports Enumerable, so you can use its goodies to your comfort without building intermediate arrays:

Saxy.parse("filename.xml", "product").map do |object|
  # map OpenStructs to ActiveRecord instances, etc.
end

You can also grab an Enumerator for external use (e.g. lazy evaluation, etc.):

enumerator = Saxy.parse("filename.xml", "product").each
lazy       = Saxy.parse("filename.xml", "product").lazy # Ruby 2.0

Multiple definitions of child objects are grouped in arrays:

webstore = Saxy.parse("filename.xml", "webstore").first
webstore.products.product.size # => 2

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request