PHP Symfony parse JSON response deserialize class constructor

Question

I am trying to parse this JSON $response body = {"low":{"networkFee":"0.00003"},"medium":{"networkFee":"0.0000428"},"high":{"networkFee":"0.00024"}}

my code:

class Low {
  private $networkFee;
}
class Medium {
  private $networkFee;
}
class High {
  private $networkFee;
}
class FeeClass{ 
  public function __construct(Low $low, Medium $medium, High $high) {
    $this->low = $low;
    $this->medium = $medium;
    $this->high = $high;
  }
}
$encoders = [new JsonEncoder()];
$normalizers = [new ObjectNormalizer()];
$serializer = new Serializer( $normalizers, $encoders );

$parsed = $serializer->deserialize((string)$response->getBody(), FeeClass::class, 'json');

var_dump("parsed:", $parsed);//I only get 3 NULL in $parsed

My dependencies:

"laravel/framework": "6.20.x",
"symfony/serializer": "5.1.x",

Answer 1

A possibility is to make the $networkFee property public for Low, Medium and High:

require 'vendor/autoload.php';

use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Serializer;

class Low {
  public $networkFee;
}

class Medium {
  public $networkFee;
}

class High {
  public $networkFee;
}

class FeeClass {
  private Low $low;
  private Medium $medium;
  private High $high;

  public function __construct(Low $low, Medium $medium, High $high) {
    $this->low = $low;
    $this->medium = $medium;
    $this->high = $high;
  }
}

$json = '{"low":{"networkFee":"0.00003"},"medium":{"networkFee":"0.0000428"},"high":{"networkFee":"0.00024"}}';

$encoders = [new JsonEncoder()];
$normalizers = [new ObjectNormalizer()];
$serializer = new Serializer( $normalizers, $encoders );
$parsed = $serializer->deserialize($json, FeeClass::class, 'json');
var_dump($parsed);

Output:

object(FeeClass)#31 (3) {
  ["low":"FeeClass":private]=>
  object(Low)#38 (1) {
    ["networkFee"]=>
    string(7) "0.00003"
  }
  ["medium":"FeeClass":private]=>
  object(Medium)#33 (1) {
    ["networkFee"]=>
    string(9) "0.0000428"
  }
  ["high":"FeeClass":private]=>
  object(High)#37 (1) {
    ["networkFee"]=>
    string(7) "0.00024"
  }
}

Alternatively you can add public constructors to Low, Medium and High:

class Low {
  private $networkFee;

  public function __construct($networkFee) {
      $this->networkFee = $networkFee;
  }
}

class Medium {
  private $networkFee;

  public function __construct($networkFee) {
      $this->networkFee = $networkFee;
  }
}

class High {
  private $networkFee;

  public function __construct($networkFee) {
      $this->networkFee = $networkFee;
  }
}