How can I bind a Symfony config tree to an object - symfony

Question

How would I go about binding a Symfony config tree to a class rather than returning an array?
Using Symfony\Component\Config\Definition\Processor returns an array.
In my case I want the config to be bound to a class so I can use methods to combine parts of the data.
Here is a simple example of my use case. I want the config bound to a class so I can use a method to join table.name and table.version together (my actual use case is more complex, but this is a simple example)
config.yml
db:
table:
name: some_table
version: v2
ConfigurationInterface
class DBConfiguration implements ConfigurationInterface
{
/**
* {#inheritDoc}
*/
public function getConfigTreeBuilder()
{
$treeBuilder = new TreeBuilder();
$rootNode = $treeBuilder->root('db');
$rootNode
->children()
->arrayNode('table')
->children()
->scalarNode('name')->isRequired()->end()
->scalarNode('version')->end()
->end()
->end()
;
return $treeBuilder;
}
}
Class I want to bind the config to
class DB
{
public $table;
public function __construct()
{
$this->table = new Table();
}
}
class Table
{
public $name;
public $version;
/**
* #return string
* Calculate the full table name.
*/
public function getTableName()
{
return $this->name.'-'.$this->version;
}
}

Answer 1

The Symfony Config component doesn't support that.
However, in a Symfony project, this is usually done at the container compile phase. In your bundle's Extension class, you will have access to the configuration tree of your bundle in array form.
You can then take this array and assign it to a service defined in the service container that will create your config object.
This is exactly how DoctrineBundle's configuration class is built:
Abstract services (for the configuration and the factory) are defined in dbal.xml
When loading DoctrineBundle's extension, an instance of the abstract config service is created for each defined connection.
An instance of the abstract factory service is created for each defined connection.
The options array is then passed to the abstract factory service along with the configuration
When creating an instance, the factory then does the necessary transformations.

Answer 2

As far as I know, Symfony has no native support for this, however, you could implement it yourself. You could use subset of Symfony Serializer Component in charge of deserialization, but I think it would be an overkill. Especially since I don't see any PublicPropertyDenormalizer, only GetSetMethodNormalizer (which is denormalizer too). Therefor you would have to either make your config objects have get/set methods or roll PublicPropertyDenormalizer on your own. Possible but it really seems like an overkill and doesn't look like helping much:
Symfony Serializer Component
$array = [
'field1' => 'F1',
'subobject' => [
'subfield1' => 'SF1',
],
];
class MyConfigObject implements Symfony\Component\Serializer\Normalizer\DenormalizableInterface
{
private $field1;
private $subobject;
public function getField1()
{
return $this->field1;
}
public function setField1($field1)
{
$this->field1 = $field1;
}
public function getSubobject()
{
return $this->subobject;
}
public function setSubobject(SubObject $subobject)
{
$this->subobject = $subobject;
}
public function denormalize(\Symfony\Component\Serializer\Normalizer\DenormalizerInterface $denormalizer, $data, $format = null, array $context = array())
{
$obj = new static();
$obj->setField1($data['field1']);
$obj->setSubobject($denormalizer->denormalize($data['subobject'], 'SubObject'));
return $obj;
}
}
class SubObject
{
private $subfield1;
public function getSubfield1()
{
return $this->subfield1;
}
public function setSubfield1($subfield1)
{
$this->subfield1 = $subfield1;
}
}
$normalizer = new \Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer();
$obj = (new MyConfigObject())->denormalize($normalizer, $array);
Native PHP Way
Imo this is a lot easier than above as Symfony Serializer wasn't really ment for that.
$array = [
'field1' => 'F1',
'subobject' => [
'subfield1' => 'SF1',
],
];
trait Denormalizable
{
public function fromArray($array)
{
foreach ($array as $property => $value) {
if (is_array($value)) {
if ($this->$property instanceof ArrayDenormalizableInterface) {
$this->$property->fromArray($value);
} else {
$this->$property = $value;
}
} else {
$this->$property = $value;
}
}
}
}
interface ArrayDenormalizableInterface
{
public function fromArray($array);
}
class MyConfigObject implements ArrayDenormalizableInterface
{
use Denormalizable;
public $field1;
public $subobject;
public function __construct()
{
$this->subobject = new SubObject();
}
}
class SubObject implements ArrayDenormalizableInterface
{
use Denormalizable;
public $subfield1;
}
$myConf = new MyConfigObject();
$myConf->fromArray($array);
Whatever way you choose, you can now just take array returned from symfony processor and turn it into a config object you need.