sonic-pi

Array#to_xml

Returns a string that represents the array in XML by invoking +to_xml+
on each element. Active Record collections delegate their representation
in XML to this method.

All elements are expected to respond to +to_xml+, if any of them does
not then an exception is raised.

The root node reflects the class name of the first element in plural
if all elements belong to the same type and that's not Hash:

  customer.projects.to_xml

  <?xml version="1.0" encoding="UTF-8"?>
  <projects type="array">
    <project>
      <amount type="decimal">20000.0</amount>
      <customer-id type="integer">1567</customer-id>
      <deal-date type="date">2008-04-09</deal-date>
      ...
    </project>
    <project>
      <amount type="decimal">57230.0</amount>
      <customer-id type="integer">1567</customer-id>
      <deal-date type="date">2008-04-15</deal-date>
      ...
    </project>
  </projects>

Otherwise the root element is "objects":

  [{ foo: 1, bar: 2}, { baz: 3}].to_xml

  <?xml version="1.0" encoding="UTF-8"?>
  <objects type="array">
    <object>
      <bar type="integer">2</bar>
      <foo type="integer">1</foo>
    </object>
    <object>
      <baz type="integer">3</baz>
    </object>
  </objects>

If the collection is empty the root element is "nil-classes" by default:

  [].to_xml

  <?xml version="1.0" encoding="UTF-8"?>
  <nil-classes type="array"/>

To ensure a meaningful root element use the <tt>:root</tt> option:

  customer_with_no_projects.projects.to_xml(root: 'projects')

  <?xml version="1.0" encoding="UTF-8"?>
  <projects type="array"/>

By default name of the node for the children of root is <tt>root.singularize</tt>.
You can change it with the <tt>:children</tt> option.

The +options+ hash is passed downwards:

  Message.all.to_xml(skip_types: true)

  <?xml version="1.0" encoding="UTF-8"?>
  <messages>
    <message>
      <created-at>2008-03-07T09:58:18+01:00</created-at>
      <id>1</id>
      <name>1</name>
      <updated-at>2008-03-07T09:58:18+01:00</updated-at>
      <user-id>1</user-id>
    </message>
  </messages>

Source | Google | Stack overflow