Value Transformation

The value transformation middleware can be used to apply a callback to the JSON value before it is mapped to the class property.

Available since JsonMapper 2.9.0

The examples below map onto the following class:

class User
{
    public string $name;
}

Using a php named function as callback#

$middleware = new \JsonMapper\Middleware\ValueTransformation('strtolower');
$mapper = (new \JsonMapper\JsonMapperFactory())->bestFit();
$mapper->unshift($middleware);
$object = new User();
 
$mapper->mapObjectFromString('{ "name": "JOHN DOE" }', $object);
 
echo $object->name; // "john doe"

Using a custom callback#

Pass true as the second constructor argument to have the property name handed to the callback alongside the value.

$middleware = new \JsonMapper\Middleware\ValueTransformation(
    static function ($key, $value) {
        if ($key === 'name') {
            return \base64_decode($value);
        }
 
        return $value;
    },
    true
);
$mapper = (new \JsonMapper\JsonMapperFactory())->bestFit();
$mapper->unshift($middleware);
$object = new User();
 
$mapper->mapObjectFromString('{ "name": "Sm9obiBEb2U=" }', $object);
 
echo $object->name; // "John Doe"