Callback Functions

Nette\Utils\Callback is a static class, which contains functions for working with PHP callbacks.

Installation:

composer require nette/utils

All examples assume the following class alias is defined:

use Nette\Utils\Callback;

check($callable, bool $syntax = false): callable

Checks that $callable is valid PHP callback. Otherwise throws Nette\InvalidArgumentException. If the $syntax is set to true, the function only verifies that $callable has a valid structure to be used as a callback, but does not verify if the class or method actually exists. Returns $callable.

Callback::check('trim'); // no exception
Callback::check(['NonExistentClass', 'method']); // throws Nette\InvalidArgumentException
Callback::check(['NonExistentClass', 'method'], true); // no exception
Callback::check(function () {}); // no exception
Callback::check(null); // throws Nette\InvalidArgumentException

toString($callable): string

Converts PHP callback to textual form. Class or method may not exists.

Callback::toString('trim');                // 'trim'
Callback::toString(['MyClass', 'method']); // 'MyClass::method'

toReflection($callable): ReflectionMethod|ReflectionFunction

Returns reflection for method or function used in PHP callback.

$ref = Callback::toReflection('trim');
// $ref is ReflectionFunction('trim')

$ref = Callback::toReflection(['MyClass', 'method']);
// $ref is ReflectionMethod('MyClass', 'method')

isStatic($callable): bool

Checks whether PHP callback is function or static method.

Callback::isStatic('trim');                // true
Callback::isStatic(['MyClass', 'method']); // true
Callback::isStatic([$obj, 'method']);      // false
Callback::isStatic(function () {});        // false

unwrap(Closure $closure): callable

Unwraps closure created by Closure::fromCallable.

$closure = Closure::fromCallable(['MyClass', 'method']);
Callback::unwrap($closure);     // ['MyClass', 'method']

closure($callable): Closure

(or closure($classOrObject, $method): Closure)

Converts PHP callback to object Closure.

$trimmer = Callback::closure('trim');
$trimmer(' hello '); // 'hello'

Since PHP 7.1 you should use native Closure::fromCallable.

invoke($callable, …$args): mixed

Calls the $callable, passes the remaining parameters as arguments and returns the returned value.

When is not callable, it throws Nette\InvalidArgumentException unlike call_user_func which only triggers a warning.

$callback = 'trim';
Callback::invoke($callback, ' hello '); // 'hello'

Since PHP 7.0 you should use native $callback($arg, ...).

invokeArgs($callable, array $args = [])mixed

Calls the $callable with $args arguments and return its value.

When is not callable, it throws Nette\InvalidArgumentException unlike call_user_func which only triggers a warning.

$callback = 'trim';
Callback::invoke($callback, [' hello ']); // 'hello'

Since PHP 7.0 you should use native $callback(...$args).