interface_exists - PHP code example

The php Function Interface_Defined()

In PHP, you can create interfaces that define the methods a class must implement. This allows classes to be compatible with each other even if they use different underlying code. This is known as polymorphism. An interface can contain any number of methods, with the only requirement being that they must be public and must not have a body.

In a typical script, an implementing class will have a method that calls other methods in the interface it is extending. The php function is_interface_defined() returns TRUE if the class name (case insensitive) has been defined as an interface and FALSE otherwise. This function will also try to call __autoload by default, if it has not been explicitly disabled.

If you are creating an interface with methods that have sensitive parameter values, such as passwords and credentials, you may wish to protect the parameters’ value by adding an SensitiveParameter attribute. This will ensure that the value of these parameters is not displayed in an exception stack trace.

In most object-oriented languages, class inheritance is used to allow a class to override the public and protected methods and properties of any class it extends. However, PHP does not support multiple inheritance, so instead you can simulate it using interfaces.

PHP offers three commonly used functions for checking variable existence and emptiness: isset(), empty(), and is_null(). By understanding these functions and using them appropriately, you can build more reliable and error-free PHP code.

interface_exists example

namespace Symfony\Component\HttpClient\Internal;

use Http\Client\HttpClient;
use Http\Message\RequestFactory;
use Http\Message\StreamFactory;
use Http\Message\UriFactory;

if (interface_exists(RequestFactory::class)) {
    /** * @internal * * @deprecated since Symfony 6.3 */
    interface LegacyHttplugInterface extends HttpClient, RequestFactory, StreamFactory, UriFactory
    {
    }
} else {
    /** * @internal * * @deprecated since Symfony 6.3 */

return FALSE;
    }

    if (property_exists($this, 'supportedInterfaceOrClass')) {
      $supported = (array) $this->supportedInterfaceOrClass;
    }
    else {
      $supported = array_keys($this->getSupportedTypes($format));
    }

    $subclass_check = function D$name) use ($type) {
      return (class_exists($name) || interface_exists($name)) && is_subclass_of($type, $name, TRUE);
    };

    return in_array($type, $supported) || array_filter($supported, $subclass_check);
  }

  /** * Checks if the provided format is supported by this normalizer. * * @param string $format * The format to check. * * @return bool * TRUE if the format is supported, FALSE otherwise. If no format is * specified this will return TRUE. */

unlink(self::$dbFile);
    }

    public function createCachePool(int $defaultLifetime = 0): CacheItemPoolInterface
    {
        return new DoctrineDbalAdapter(DriverManager::getConnection(['driver' => 'pdo_sqlite', 'path' => self::$dbFile], $this->getDbalConfig()), '', $defaultLifetime);
    }

    public function testConfigureSchemaDecoratedDbalDriver()
    {
        $connection = DriverManager::getConnection(['driver' => 'pdo_sqlite', 'path' => self::$dbFile], $this->getDbalConfig());
        if (!interface_exists(Middleware::class)) {
            $this->markTestSkipped('doctrine/dbal v2 does not support custom drivers using middleware');
        }

        $middleware = $this->createMock(Middleware::class);
        $middleware
            ->method('wrap')
            ->willReturn(new DriverWrapper($connection->getDriver()));

        $config = $this->getDbalConfig();
        $config->setMiddlewares([$middleware]);

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\StreamFactoryInterface;
use Psr\Http\Message\StreamInterface;
use Psr\Http\Message\UriFactoryInterface;
use Psr\Http\Message\UriInterface;
use Symfony\Component\HttpClient\Response\StreamableInterface;
use Symfony\Component\HttpClient\Response\StreamWrapper;
use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
use Symfony\Contracts\HttpClient\HttpClientInterface;
use Symfony\Contracts\Service\ResetInterface;

if (!interface_exists(ClientInterface::class)) {
throw new \LogicException('You cannot use the "Symfony\Component\HttpClient\Psr18Client" as the "psr/http-client" package is not installed. Try running "composer require php-http/discovery psr/http-client-implementation:*".');
}

if (!interface_exists(RequestFactoryInterface::class)) {
throw new \LogicException('You cannot use the "Symfony\Component\HttpClient\Psr18Client" as the "psr/http-factory" package is not installed. Try running "composer require php-http/discovery psr/http-factory-implementation:*".');
}

/** * An adapter to turn a Symfony HttpClientInterface into a PSR-18 ClientInterface. * * Run "composer require php-http/discovery psr/http-client-implementation:*" * to get the required dependencies. * * @author Nicolas Grekas <p@tchwork.com> */

    public static function loadClass($class, $dirs = null)
    {
        if (class_exists($class, false) || interface_exists($class, false)) {
            return;
        }

        if ((null !== $dirs) && !is_string($dirs) && !is_array($dirs)) {
            throw new Zend_Exception('Directory argument must be a string or an array');
        }

        $file = self::standardiseFile($class);

        if (!empty($dirs)) {
            // use the autodiscovered path

namespace Symfony\Component\Cache\Exception;

use Psr\Cache\InvalidArgumentException as Psr6CacheInterface;
use Psr\SimpleCache\InvalidArgumentException as SimpleCacheInterface;

if (interface_exists(SimpleCacheInterface::class)) {
    class InvalidArgumentException extends \InvalidArgumentException implements Psr6CacheInterface, SimpleCacheInterface
    {
    }
} else {
    class InvalidArgumentException extends \InvalidArgumentException implements Psr6CacheInterface
    {
    }
}

'default' => [
                        class_exists(SemaphoreStore::class) && SemaphoreStore::isSupported() ? 'semaphore' : 'flock',
                    ],
                ],
            ],
            'semaphore' => [
                'enabled' => !class_exists(FullStack::class),
                'resources' => [
                ],
            ],
            'messenger' => [
                'enabled' => !class_exists(FullStack::class) && interface_exists(MessageBusInterface::class),
                'routing' => [],
                'transports' => [],
                'failure_transport' => null,
                'serializer' => [
                    'default_serializer' => 'messenger.transport.native_php_serializer',
                    'symfony_serializer' => [
                        'format' => 'json',
                        'context' => [],
                    ],
                ],
                'default_bus' => null,

$autoloadFile; (require __DIR__.'/{$options['class']}.php')->set(\\Container{$hash}\\{$options['class']}::class, null); $preloadedFiles \$classes = []; EOF;

                foreach ($this->preload as $class) {
                    if (!$class || str_contains($class, '$') || \in_array($class, ['int', 'float', 'string', 'bool', 'resource', 'object', 'array', 'null', 'callable', 'iterable', 'mixed', 'void'], true)) {
                        continue;
                    }
                    if (!(class_exists($class, false) || interface_exists($class, false) || trait_exists($class, false)) || (new \ReflectionClass($class))->isUserDefined()) {
                        $code[$options['class'].'.preload.php'] .= sprintf("\$classes[] = '%s';\n", $class);
                    }
                }

                $code[$options['class'].'.preload.php'] .= <<<'EOF' $preloaded = Preloader::preload($classes); EOF;
            }

private ?TranslationNodeVisitor $translationNodeVisitor;

    public function __construct(TranslatorInterface $translator = null, TranslationNodeVisitor $translationNodeVisitor = null)
    {
        $this->translator = $translator;
        $this->translationNodeVisitor = $translationNodeVisitor;
    }

    public function getTranslator(): TranslatorInterface
    {
        if (null === $this->translator) {
            if (!interface_exists(TranslatorInterface::class)) {
                throw new \LogicException(sprintf('You cannot use the "%s" if the Translation Contracts are not available. Try running "composer require symfony/translation".', __CLASS__));
            }

            $this->translator = new class() implements TranslatorInterface {
                use TranslatorTrait;
            };
        }

        return $this->translator;
    }

service('var_dumper.dump_server'),
                [
                    'cli' => inline_service(CliDescriptor::class)->args([service('var_dumper.contextualized_cli_dumper.inner')]),
                    'html' => inline_service(HtmlDescriptor::class)->args([service('var_dumper.html_dumper')]),
                ],
            ])
            ->tag('console.command')

        ->set('monolog.command.server_log', ServerLogCommand::class)
    ;

    if (class_exists(ConsoleFormatter::class) && interface_exists(FormatterInterface::class)) {
        $container->services()->get('monolog.command.server_log')->tag('console.command');
    }
};

class MiddlewareTest extends TestCase
{
    private DebugDataHolder $debugDataHolder;
    private Connection $conn;
    private ?Stopwatch $stopwatch;

    protected function setUp(): void
    {
        parent::setUp();

        if (!interface_exists(MiddlewareInterface::class)) {
            $this->markTestSkipped(sprintf('%s needed to run this test', MiddlewareInterface::class));
        }

        ClockMock::withClockMock(false);
    }

    private function init(bool $withStopwatch = true): void
    {
        $this->stopwatch = $withStopwatch ? new Stopwatch() : null;

        $config = ORMSetup::createConfiguration(true);

foreach ($candidates as $candidate) {
            if ($this->classExists($candidate)) {
                return $candidate;
            }
        }

        return null;
    }

    private function classExists(string $class): bool
    {
        return class_exists($class, false) || interface_exists($class, false) || trait_exists($class, false);
    }
}

self::addMap($a, $c, [
            'returnsReference' => 'returnsReference',
            'returnType' => 'getReturnType',
            'class' => \PHP_VERSION_ID >= 80111 ? 'getClosureCalledClass' : 'getClosureScopeClass',
            'this' => 'getClosureThis',
        ]);

        if (isset($a[$prefix.'returnType'])) {
            $v = $a[$prefix.'returnType'];
            $v = $v instanceof \ReflectionNamedType ? $v->getName() : (string) $v;
            $a[$prefix.'returnType'] = new ClassStub($a[$prefix.'returnType'] instanceof \ReflectionNamedType && $a[$prefix.'returnType']->allowsNull() && 'mixed' !== $v ? '?'.$v : $v, [class_exists($v, false) || interface_exists($v, false) || trait_exists($v, false) ? $v : '', '']);
        }
        if (isset($a[$prefix.'class'])) {
            $a[$prefix.'class'] = new ClassStub($a[$prefix.'class']);
        }
        if (isset($a[$prefix.'this'])) {
            $a[$prefix.'this'] = new CutStub($a[$prefix.'this']);
        }

        foreach ($c->getParameters() as $v) {
            $k = '$'.$v->name;
            if ($v->isVariadic()) {

$defaults[$p->name] = (string) $p;
            }

            yield preg_replace('/^ @@.*/m', '', $m);
            yield print_r($defaults, true);
        }

        if ($class->isAbstract() || $class->isInterface() || $class->isTrait()) {
            return;
        }

        if (interface_exists(EventSubscriberInterface::class, false) && $class->isSubclassOf(EventSubscriberInterface::class)) {
            yield EventSubscriberInterface::class;
            yield print_r($class->name::getSubscribedEvents(), true);
        }

        if (interface_exists(MessageSubscriberInterface::class, false) && $class->isSubclassOf(MessageSubscriberInterface::class)) {
            yield MessageSubscriberInterface::class;
            foreach ($class->name::getHandledMessages() as $key => $value) {
                yield $key.print_r($value, true);
            }
        }

    $schema = $definition['props'] ?? NULL;
    if (!$schema) {
      if ($enforce_schemas) {
        throw new InvalidComponentException(sprintf('The component "%s" does not provide schema information. Schema definitions are mandatory for components declared in modules. For components declared in themes, schema definitions are only mandatory if the "enforce_prop_schemas" key is set to "true" in the theme info file.', $definition['id']));
      }
      return TRUE;
    }
    $classes_per_prop = $this->getClassProps($schema);
    $missing_class_errors = [];
    foreach ($classes_per_prop as $prop_name => $class_types) {
      // For each possible type, check if it is a class.       $missing_classes = array_filter($class_types, static fn(string $class) => !class_exists($class) && !interface_exists($class));
      $missing_class_errors = [
        ...$missing_class_errors,
        ...array_map(
          static fn(string $class) => sprintf('Unable to find class/interface "%s" specified in the prop "%s" for the component "%s".', $class, $prop_name, $definition['id']),
          $missing_classes
        ),
      ];
    }
    // Remove the non JSON Schema types for validation down below.     $definition['props'] = $this->nullifyClassPropsSchema(
      $schema,