Flowdock
method

to_xml

Importance_3
v3.2.13 - Show latest stable - 1 note - Class: Hash
to_xml(options = {}) public

Returns a string containing an XML representation of its receiver:

{"foo" => 1, "bar" => 2}.to_xml
# =>
# <?xml version="1.0" encoding="UTF-8"?>
# <hash>
#   <foo type="integer">1</foo>
#   <bar type="integer">2</bar>
# </hash>

To do so, the method loops over the pairs and builds nodes that depend on the values. Given a pair key, value:

  • If value is a hash there’s a recursive call with key as :root.

  • If value is an array there’s a recursive call with key as :root, and key singularized as :children.

  • If value is a callable object it must expect one or two arguments. Depending on the arity, the callable is invoked with the options hash as first argument with key as :root, and key singularized as second argument. The callable can add nodes by using options[:builder].

    "foo".to_xml(lambda { |options, key| options[:builder].b(key) })
    # => "<b>foo</b>"
    
  • If value responds to to_xml the method is invoked with key as :root.

    class Foo
      def to_xml(options)
        options[:builder].bar "fooing!"
      end
    end
    
    {:foo => Foo.new}.to_xml(:skip_instruct => true)
    # => "<hash><bar>fooing!</bar></hash>"
    
  • Otherwise, a node with key as tag is created with a string representation of value as text node. If value is nil an attribute “nil” set to “true” is added. Unless the option :skip_types exists and is true, an attribute “type” is added as well according to the following mapping:

    XML_TYPE_NAMES = {
      "Symbol"     => "symbol",
      "Fixnum"     => "integer",
      "Bignum"     => "integer",
      "BigDecimal" => "decimal",
      "Float"      => "float",
      "TrueClass"  => "boolean",
      "FalseClass" => "boolean",
      "Date"       => "date",
      "DateTime"   => "datetime",
      "Time"       => "datetime"
    }
    

By default the root node is “hash”, but that’s configurable via the :root option.

The default XML builder is a fresh instance of Builder::XmlMarkup. You can configure your own builder with the :builder option. The method also accepts options like :dasherize and friends, they are forwarded to the builder.

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September 13, 2011
0 thanks

more options

useful options are:

:root => ‘object’, :skip_instruct => true, :indent => 2

:builder can also be used to pass your own Builder::XmlMarkup instance.