When working on a PHP codebase, one thing I really miss from the Typescript world is the ability to pass properly typed objects and array into functions.
Been searching around for a proper solution in PHP and remembered the DTO concept today, which led me to Spatie’s data-transfer-object package.
It perfectly embodies what I’ve been looking for, only issue being you can’t just declare an object is PHP with braces like in Javascript 😁. So instead we create a new namespace in the project under which we keep the DTO files, e.g App\DataTransferObjects.
For a use case, I have this service App\Services\MobileMoneyPaymentService. It has a method requestPayment which sends a POST payment request to a payment server. This method currently looks like this:
<?php
namespace App\Services;
use App\AirtimeRequest;
use Zttp\Zttp;
use Zttp\ZttpResponse;
class MobileMoneyPaymentService
{
/** @var string $paymentServerUrl */
protected $paymentServerUrl;
public function __construct()
{
$this->paymentServerUrl = env('PAYMENT_SERVER_URL');
}
/**
* @param AirtimeRequest $airtimeRequest
* @return ZttpResponse
*/
public function requestPayment(AirtimeRequest $airtimeRequest): ZttpResponse
{
$payload = [
'amount' => $airtimeRequest->amount,
'phone' => $airtimeRequest->payer,
'external_id' => '*****',
'notification_url' => '*****',
'reference' => '*****',
'payer_message' => 'Top up',
'payee_note' => 'Top up',
];
return Zttp::post("$this->paymentServerUrl/mtn-mobile-money", $payload);
}
}
I would like to refactor requestPayment method to receive a RequestPaymentData object instead, so let’s go ahead and create the \App\DataTransferObjects\RequestPaymentData class.
Please note i’ve already installed the spatie/data-transfer-object package via composer with composer require spatie/data-transfer-object.
<?php
namespace App\DataTransferObjects;
use Spatie\DataTransferObject\DataTransferObject;
class RequestPaymentData extends DataTransferObject
{
/** @var integer */
public $amount;
/** @var string */
public $phone;
/** @var integer */
public $external_id;
/** @var string */
public $notification_url;
/** @var string */
public $reference;
/** @var string */
public $payer_message;
/** @var string */
public $payee_note;
}
Having created the class, we can now refactor the requestPayment method to accept it as follows.
<?php
namespace App\Services;
use App\AirtimeRequest;
use Zttp\Zttp;
use Zttp\ZttpResponse;
class MobileMoneyPaymentService
{
/** @var string $paymentServerUrl */
protected $paymentServerUrl;
public function __construct()
{
$this->paymentServerUrl = env('PAYMENT_SERVER_URL');
}
/**
* @param RequestPaymentData $requestPaymentData
* @return ZttpResponse
*/
public function requestPayment(RequestPaymentData $requestPaymentData): ZttpResponse
{
return Zttp::post("$this->paymentServerUrl/mtn-mobile-money", $requestPaymentData->toArray());
}
}
With this setup, am always sure all the data passed in is actually set and of the correct type. The package throws a TypeError if the value doesn’t comply with the given type 🙂.
You can learn more by having a look at it’s Readme, there’s a lot more you can do with it!