How to convert Json data directly into xml - standardized way?

Question

I'm having a Json:

[{"S":"a","D":"b"},{"S":"s1","D":"m1"},{"S":"2","D":"3"},{"S":"4","D":"5"}]

And I want it to convert into XML:

<?xml version="1.0" encoding="ISO-8859-1"?>
<Us>
    <U1>
        <S>a</S>
        <D>b</D>
    </U1>
    <U1>
        <S>s1</S>
        <D>m1</D>
    </U1>
</Us>

I know the php way, first decoding json using Json_decode() and a bunch of foreach loop that finally generate XML.

But I want in Drupal way. There is a module serialization in core of Drupal 8. But don't know how can I take the services from that module in my custom one.

Also, I got a link, How to get it done using symfony, but again it seems like Drupal 8 standards are lacking somewhere by me.

What's the right approach to achieve this in Drupal way.

Answer 1

The Serializer component is a tool in your Drupal toolbox that should be used when you need to serialize and deserialize data from and to Drupal data such as entities. Unfortunately you cannot deserialize into a \StdClass without implementing your own normalizer.

Inject the serializer service into your class, and use the serialize method to normalize the non-Drupal decoded JSON array into XML.

// Inject this instead of using \Drupal
$serializer = \Drupal::get('serializer');
// Use json_decode or @4k4's example above and use associative arrays instead of object.
$json = json_decode('[{"S":"a","D":"b"},{"S":"s1","D":"m1"},{"S":"2","D":"3"},{"S":"4","D":"5"}]', TRUE);
// Unfortunately it seems that for an array serializer xml_root_node_name won't work so wrap $json in the root name.
$data = ['US' => $json];
// Serialize into XML.
$xml = $serializer->serialize(
  $data,
  'xml',
  ['xml_root_node_name' => 'US']);