PHP Tip: Call Invoke type class in instance

PHP's __invoke is a very useful feature that can maintain a single responsibility of a class

Example

class Invokable
{
    public function __invoke()
    {
        echo '已被 invoke';
    }
}

Using

$invokable = new Invokable();
$invokable();

Invokeable classes can be injected into other classes

class Foo
{
    protected $invokable;
    public function __construct(Invokable $invokable)
    {
       $this->invokable = $invokable;
    }
    public function callInvokable()
    {
        $this->invokable();
    }
}

Use $this->invokable(); to activate the Invokable class. The class will look for a method named invokable, so the following operation will report an error

$foo = new Foo($invokable);
$foo->callInvokable();
// Call to undefined method Foo::invokable()

The following is correct Calling method

public function callInvokable()
{
    // 优先推荐
    call_user_func($this->invokable);
    // 可选
    $this->invokable->__invoke();
    // 可选
    ($this->invokable)();
}

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