ROXML Ruby Object to XML mapping library.

For more information visit:

http://rdoc.info/projects/Empact/roxml
http://empact.github.com/roxml/

Please submit bugs here:

http://github.com/Empact/roxml/issues

=Quick Start Guide

This is a short usage example. See ROXML::ClassMethods::Declarations and packaged test cases for more information.

==Basic Mapping

Consider an XML document representing a Library containing a number of Books. You can map this structure to Ruby classes that provide addition useful behavior. With ROXML, you can annotate the Ruby classes as follows:

class Book include ROXML

xml_accessor :isbn, :from => "@ISBN" # attribute with name 'ISBN'
xml_accessor :title
xml_accessor :description, :cdata => true  # text node with cdata protection
xml_accessor :author

end

class Library include ROXML

xml_accessor :name, :from => "NAME", :cdata => true
xml_accessor :books, :as => [Book] # by default roxml searches for books for in <book> child nodes, then, if none are present, in ./books/book children

end

To create a library and put a number of books in it we could run the following code:

book = Book.new book.isbn = "0201710897" book.title = "The PickAxe" book.description = "Best Ruby book out there!" book.author = "David Thomas, Andrew Hunt, Dave Thomas"

lib = Library.new lib.name = "Favorite Books" lib.books = [book]

To save this information to an XML file:

doc = Nokogiri::XML::Document.new doc.root = lib.to_xml open("library.xml", 'w') do |file| file << doc.serialize end

doc = LibXML::XML::Document.new doc.root = lib.to_xml doc.save("library.xml")

To later populate the library object from the XML file:

lib = Library.from_xml(File.read("library.xml"))

Similarly, to do a one-to-one mapping between XML objects, such as book and publisher, you would add a reference to another ROXML class. For example:

Programming Ruby - 2nd Edition Second edition of the great book. Pragmatic Bookshelf

can be mapped using the following code:

class Publisher include ROXML

xml_accessor :name

# other important functionality

end

class BookWithPublisher include ROXML

xml_name 'book'
xml_reader :publisher, :as => Publisher

#  or, alternatively, if no class is needed to hang functionality on:
# xml_reader :publisher, :from => 'name', :in => 'publisher'

end

Note: In the above example, _xmlname annotation tells ROXML to set the element name to "book" for mapping to XML. The default is XML element name is the class name in lowercase; "bookwithpublisher" in this case.

=== Namespace Support

Namespaced nodes are supported via the xml_namespace and xml_namespaces declarations and the :from and :namespace attr options. See spec/xml/namespace_spec.rb for usage.

Note that ROXML does not currently support outputting namespaced nodes. This is planned for a future version.

== Manipulation

Extending the above examples, say you want to parse a book's page count and have it available as an Integer. In such a case, you can extend any object with a block to manipulate it's value at parse time. For example:

class Dog include ROXML

xml_reader(:age, :from => '@human_years', :as => Integer) {|years| years * 7 }

end

The result of the block above is stored, rather than the actual value parsed from the document.

== Construction

Object life-cycle is as follows: .from_xml is called with a first argument representing the xml in file, string, or path form, and with optional initialization_args following.

Firt .new and thus #initialize, is called with those same initialization_args, or no args if none are present. Then the object is populated with the attribute values from xml. Then the

after_parse callback is called, with no arguments.

In #after_parse you can ensure that your object initialization is complete, including initialization which requires more than one variable in concert.

E.g.:

class Measurement include ROXML

xml_reader :units, :from => :attr
xml_reader :value, :from => :content

def initialize(value = 0, units = 'meters')
  to_metric
end

private def after_parse

xml attributes of self are already valid

  to_metric
end

def to_metric
  # translate units & value into metric, for example
end

end

One important use of this approach is to make ROXML object which may or may not include an xml backing, which may be used via new construction as well as _fromxml construction.

== Selecting a parser

By default, ROXML will use Nokogiri if it is available, followed by LibXML. If you'd like to explicitly require one or the other, you may do the following:

module ROXML XML_PARSER = 'nokogiri' # or 'libxml' end require 'roxml'

For more information on available annotations, see ROXML::ClassMethods::Declarations

== Note on Patches/Pull Requests

Fork the project.
Make your feature addition or bug fix.
Add specs for it. This is important so I don't break it in a future version unintentionally.
Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
Send me a pull request. Bonus points for topic branches.

Empact / roxml

readme

after_parse callback is called, with no arguments.

xml attributes of self are already valid