czt08883/typed-callable

TypedCallable

Abstract PHP class, which allows to implement callables with signature check, _(*1)

Installation

composer require czt08883/typed-callable dev-master

Usage

Define your own class extending TypedCallable, _(*2)

use Czt08883\TypedCallable\TypedCallable\TypedCallable;


class OnDataCallable extends TypedCallable 
{
    /**
     * Implement "useTemplate()" abstract method.
     * This method must return a callable, which will
     * be used as a template for signature check.
     *
     * @return callable
     */
    public function useTemplate()
    {
        return function(SomeClass $a, array $b, $c){};
    }
}    

In your other class, which requires typed callable:, _(*3)

• store this typed callable as a property

• invoke this typed callable on some event, passing some data, _(*4)

  class DataReceiverExample {, _(*5)

  /**
   * @var OnDataCallable
   */ 
  private $onDataCallback;
  
  /**
   * Use this typed callable as an argument in some function
   * to setup a callback
   */
  public function setOnDataCallback(OnDataCallable $callback)
  {
      $this->onDataCallback = $callback;
  }
  
  /**
   * Execute your callback on some event, passing proper parameters.
   * For example, on receiving data from external source
   */
   public function onData()
   {
      // ... receive some data and pass it to callback ...
      call_user_func(
          $this->onDataCallback, 
          [
              new SomeClass, 
              ['some','data','as','array'], 
              "some string" 
          ]
      );
   }

  }, _(*6)

Use your DataReceiverExample, _(*7)

  $dataReceiver = new DataReceiverExample();
  $dataReceiver->setOnDataCallback(
      new OnDataCallable(
         function (SomeClass $a, array $b, $c) {
            // just display it, for example
            echo "Yay, received some data.";
         }
      )
  );

  /* Simulate incoming data event:
   * This will invoke a callback, installed earlier. So output will be
   *     "Yay, received some data."
   */
  $dataReceiver->onData();

Now let us test callback with wrong signature. Following code will trigger TypedCallableSignatureMismatchException with following message: "Callable signature mismatch. Callable must be: function(SomeClass $a, array $b, $c){...}", _(*8)

   $dataReceiver->setOnDataCallback(
        new OnDataCallable(
           function (SomeOtherClass $c) {
             // ... other actions, not important here
           }
        )
    );