__destruct() magic method

The __destruct() is an interesting magic method which triggers at the very end of all the object's references.

First Example

class DatabaseWrapper
{
	public function __construct(){
		var_dump('connection open');
	}

	public function query($query){
		var_dump('run ' . $query);
	}

	public function __destruct(){
		var_dump('connection closed');
	}
}

$wrapper = new DatabaseWrapper();
$wrapper->query('select * from users');

This is a very basic example to understand how __destruct() magic method works. In this example, we’ve a simple scenario where a database connection opens, we runs a query and later close the connection. If we run this script, we’ll get the following output.

string(15) "connection open"
string(23) "run select * from users"
string(17) "connection closed"

Hence as we’ve seen __destruct() magic method triggers at the very end of all the references withing the class.

Another Example (Job Dispatcher)

Again this example inspired from Laravel, and we’ll create a simple job dispatcher class and look at how __destruct() magic method works here.

We’ll be creating a simple email dispatcher and we’d want to implement a delay of 5 minutes before each dispatch. Here we’ve used a Dispatchable trait, if you’re not familiar with what a trait does, you can check out Traits in PHP.

class Job
{
	public $delay = 0;

	public function delay($delay){
		$this->delay = $delay;
	}
}

trait Dispatchable
{
	public function dispatch(){
		return new PendingDispatch(new static);
	}
}

class PendingDispatch
{

	protected $job;
	public function __construct(Job $job){
		$this->job = $job;
	}

	public function delay($delay){
		$this->job->delay($delay);
		return $this;
	}

	public function __destruct(){
		var_dump('dispatched job ' . get_class($this->job) . ' with a delay of '. $this->job->delay);
	}

}
class EmailUser extends Job
{
	use Dispatchable;
	public function handle(){
		var_dump("send email to user");
	}
}

$job = new EmailUser();
$job->dispatch()->delay(5);

As you can see, we’ve used the __destruct() magic method in PendingDispatch class as delay() is the last of references or operations to run and we can put our __destruct() magic method there.