Property exists recursive version

property_exists_recursive.php

<?php

/**
 * Tell whether the propety or the inner property exists
 * we do not use isset as isset($obj->foo->bar->baz) would return false
 * if $obj->foo->bar->baz = null
 *
 * Usage:
 *
 * if (property_exists($obj, 'foo->bar->baz')) {
 *     echo $obj->foo->bar->baz;
 * }
 *
 * @param object $object a PHP object
 * @param string $path the property path
 * @param string $separator the property separator by default '->' is used
 *
 * @return bool
 */
function property_exists_recursive($object, string $path, string $separator = '->'): bool
{
    if (!is_object($object)) {
        return false;
    }

    $properties = explode($separator, $path);
    $property = array_shift($properties);
    if (!property_exists($object, $property)) {
        return false;
    }

    try {
        $object = $object->$property;
    } catch (Throwable $e) {
        return false;
    }

    if (empty($properties)) {
        return true;
    }

    return property_exists_recursive($object, implode('->', $properties));
}


/// TEST

// Create a handler function
$assert_handler = function ($file, $line, $code, $desc = null)
{
    echo "Assertion failed";
    if (isset($desc) && '' !== $desc) {
        echo ": $desc";
    }
    echo PHP_EOL;
};

// Set up the callback
assert_options(ASSERT_ACTIVE, 1);
assert_options(ASSERT_WARNING, 0);
assert_options(ASSERT_QUIET_EVAL, 1);
assert_options(ASSERT_CALLBACK, $assert_handler);

// Simple stdClass
$obj = (object) ['toto' => (object) ['foo' => (object) ['bar' => (object) ['baz' => 'cool']]]];

// Full fledge class
class Toto
{
    private $foo;

    private $forbidden;

    public function __construct()
    {
        $this->foo = (object) ['toto' => (object) ['foo' => (object) ['bar' => (object) ['baz' => 'cool']]]];
        $this->forbidden = (object) ['toto' => (object) ['foo' => (object) ['bar' => (object) ['baz' => 'cool']]]];
    }

    public function __get($name)
    {
        if (property_exists($this, $name) && 'forbidden' !== $name) {
            return $this->$name;
        }
    }
}

echo '<pre>', PHP_EOL;
assert(property_exists_recursive($obj, 'toto->foo->bar->baz'));
assert(property_exists_recursive($obj, 'toto->foo->toto->baz'), 'the toto property does not exists');
assert(property_exists_recursive(new Toto, 'foo->toto->foo'));
assert(property_exists_recursive(new Toto, 'forbidden->toto->foo'), 'the private $forbidden property is not accessible');