Halo. Sangat sering, ketika bekerja dengan kode lama (dan terkadang tidak begitu), atau mencoba menggunakan semacam pustaka, Anda mengalami pembatasan ekstensi. Seringkali tidak akan ada masalah jika kode itu melek arsitektur. Ada banyak aturan dan pola arsitektural yang pada akhirnya mempermudah untuk memperluas kode, refactor, dan penggunaan kembali Anda. Pada artikel ini saya ingin menyinggung beberapa di antaranya dalam contoh.
Dahulu kala, dalam proyek yang jauh, sebuah layanan muncul yang mengirimkan surat dengan kata sandi baru ke pengguna. Sesuatu seperti ini:
<?php
class ReminderPasswordService
{
protected function sendToUser($user, $message)
{
$this->getMailer()->send([
'from' => 'admin@example.com',
'to' => $user['email'],
'message' => $message
]);
}
public function sendReminderPassword($user, $password)
{
$message = $this->prepareMessage($user, $password);
$this->sendToUser($user, $message);
}
protected function prepareMessage($user, $password)
{
$userName = $this->escapeHtml($user['first_name']);
$password = $this->escapeHtml($password);
$message = " {$userName}!
{$password}";
$message = $this->format($message);
$message = $this->addHeaderAndFooter($message);
return $message;
}
protected function format($message)
{
return nl2br($message);
}
protected function escapeHtml($string)
{
return htmlentities($string);
}
protected function addHeaderAndFooter($message)
{
$message = "<html><body>{$message}<br> , !</body>";
return $message;
}
protected function getMailer()
{
return new Mailer('user', 'password', 'smtp.example.com');
}
}
, .. , , , - . , , , , . - . plainText, HTML. ( , , ).
<?php
class ReminderPasswordCopyToManagerService extends ReminderPasswordService
{
protected function send($user, $message)
{
$this->getMailer()->send([
'from' => 'admin@example.com',
'to' => 'manager@example.com',
'message' => $message
]);
}
protected function prepareMessage($user, $password)
{
$userName = $this->escapeHtml($user['first_name']);
$message = " {$userName}!
****";
return $message;
}
protected function getMailer()
{
return new Mailer('user2', 'password2', 'smtp.corp.example.com');
}
}
, , . smtp API . Mailer , . , , ?
Dependency Injection ( , DI)
DI - , , - , .
, . , , - . , - , . . Unit . , - DI, . :
<?php
class ReminderPasswordService
{
/**
* @var Mailer
*/
protected $mailer;
public function __construct(Mailer $mailer)
{
$this->mailer = $mailer;
}
// getMailer, protected $mailer
// ...
}
, getMailer():
<?php
class ReminderPasswordCopyToManagerService extends ReminderPasswordService
{
protected function send($to, $message)
{
$this->mailer->send([
'from' => 'admin@example.com',
'to' => 'manager@example.com',
'message' => $message
]);
}
protected function prepareMessage($user, $password)
{
$userName = $this->escapeHtml($user['first_name']);
$message = " {$userName}!
****";
return $message;
}
}
, , . , Mailer, ( , , ) . , , .
(Dependency Inversion Principle, DIP)
- , . - .
. , , , . : , .
<?php
interface MailerInterface
{
public function send($emailFrom, $emailTo, $message);
}
.. - - MailMessageInterface , .
<?php
interface MailMessageInterface
{
public function setFrom($from);
public function getFrom();
public function setTo($to);
public function getTo();
public function setMessage($message);
public function getMessage();
}
MailSenderInterface, ,
<?php
interface MailerInterface
{
public function send(MailMessageInterface $message);
}
- MailMessageInterface,
<?php
interface MailMessageFactoryInterface
{
public function create(): MailMessageInterface;
}
, ,
<?php
class ReminderPasswordService
{
/**
* @var MailerInterface
*/
protected $mailer;
/**
* @var MailMessageFactoryInterface
*/
protected $messageFactory;
public function __construct(MailerInterface $mailer, MailMessageFactoryInterface $messageFactory)
{
$this->mailer = $mailer;
$this->messageFactory = $messageFactory;
}
protected function send($user, $messageText)
{
$message = $this->messageFactory->create();
$message->setFrom('admin@example.com');
$message->setTo($user['email']);
$message->setMessage($messageText);
$this->mailer->send($message);
}
//
public function sendReminderPassword($user, $password)
{
$message = $this->prepareMessage($user, $password);
$this->sendToUser($user, $message);
}
protected function prepareMessage($user, $password)
{
$userName = $this->escapeHtml($user['first_name']);
$password = $this->escapeHtml($password);
$message = " {$userName}!
{$password}";
$message = $this->format($message);
$message = $this->addHeaderAndFooter($message);
return $message;
}
protected function format($message)
{
return nl2br($message);
}
protected function escapeHtml($string)
{
return htmlentities($string);
}
protected function addHeaderAndFooter($message)
{
$message = "<html><body>{$message}<br> , !</body>";
return $message;
}
}
, , . .
<?php
class ReminderPasswordCopyToManagerService extends ReminderPasswordService
{
protected function send($to, $messageText)
{
$message = $this->messageFactory->create();
$message->setFrom('admin@example.com');
$message->setTo('manager@example.com');
$message->setMessage($messageText);
$this->mailer->send($message);
}
protected function prepareMessage($user, $password)
{
$userName = $this->escapeHtml($user['first_name']);
$message = " {$userName}!
****";
return $message;
}
}
VS
- . - , .
:
1. , .
2. , protected/private
3. , - - .
, , - , , . 90% ( , , ), .
, . , API, -
<?php
class SomeAPIService implements SomeAPIServiceInterface
{
public function getSomeData($someParam)
{
$someData = [];
// ...
return $someData;
}
}
, , . :
<?php
class SomeApiServiceCached extends SomeAPIService
{
public function getSomeData($someParam)
{
$cachedData = $this->getCachedData($someParam);
if ($cachedData === null) {
$cachedData = parent::getSomeData($someParam);
$this->saveToCache($someParam, $cachedData);
}
return $cachedData;
}
// ...
}
API , , DIP, .
<?php
class SomeApiServiceCached implements SomeAPIServiceInterface
{
private $someApiService;
public function __construct(SomeApiServiceInterface $someApiService)
{
$this->someApiService = $someApiService;
}
public function getSomeData($someParam)
{
$cachedData = $this->getCachedData($someParam);
if ($cachedData === null) {
$cachedData = $this->someApiService->getSomeData($someParam);
$this->saveToCache($someParam, $cachedData);
}
return $cachedData;
}
// ...
}
, , .
ReminderPasswordCopyToManagerService , " ". , - addHeaderAndFooter format, prepareMessage ( - (Open-Closed Principe), , ),
Umum - isi pesan, metode escapeHtml .
Mari kita coba membawa sang jenderal ke dalam kelas yang terpisah.
<?php
class ReminderPasswordMessageTextBuilder
{
public function buildMessageText($userName, $password)
{
return " {$userName}!
{$password}";
}
}
class Escaper
{
public function escapeHtml($string)
{
return htmlentities($string);
}
}
Jika kita melihat perbedaannya, maka secara umum kedua layanan tersebut hanya berbeda pada teks pesannya, serta pada penerimanya. Mari kita tulis ulang kedua layanan sehingga tidak bergantung satu sama lain dan hanya berisi perbedaan.
<?php
class ReminderPasswordService
{
// ,
private $mailer;
private $messageFactory;
private $escaper;
private $messageTextBuilder;
public function __construct(
MailerInterface $mailer,
MailMessageFactoryInterface $messageFactory,
Escaper $escaper,
ReminderPasswordMessageTextBuilder $messageTextBuilder
) {
$this->mailer = $mailer;
$this->messageFactory = $messageFactory;
$this->escaper = $escaper;
$this->messageTextBuilder = $messageTextBuilder;
}
public function sendReminderPassword($user, $password)
{
$messageText = $this->prepareMessage($user, $password);
$message = $this->messageFactory->create();
$message->setFrom('admin@example.com');
$message->setTo($user['email']);
$message->setMessage($messageText);
$this->mailer->send($message);
}
private function prepareMessage($user, $password)
{
$userName = $this->escaper->escapeHtml($user['first_name']);
$password = $this->escaper->escapeHtml($password);
$message = $this->messageTextBuilder->buildMessageText($userName, $password);
$message = $this->format($message);
$message = $this->addHeaderAndFooter($message);
return $message;
}
// .
private function addHeaderAndFooter($message)
{
$message = "<html><body>{$message}<br> , !</body>";
return $message;
}
private function format($message)
{
return nl2br($message);
}
}
dan mantan ahli waris
<?php
class ReminderPasswordCopyToManagerService
{
private $mailer;
private $messageFactory;
private $escaper;
private $messageTextBuilder;
public function __construct(
MailerInterface $mailer,
MailMessageFactoryInterface $messageFactory,
Escaper $escaper,
ReminderPasswordMessageTextBuilder $messageTextBuilder
) {
$this->mailer = $mailer;
$this->messageFactory = $messageFactory;
$this->escaper = $escaper;
$this->messageTextBuilder = $messageTextBuilder;
}
public function sendReminderPasswordCopyToManager($user)
{
$messageText = $this->prepareMessage($user);
$message = $this->messageFactory->create();
$message->setFrom('admin@example.com');
$message->setTo($user['email']);
$message->setMessage($messageText);
$this->mailer->send($message);
}
private function prepareMessage($user)
{
$userName = $this->escaper->escapeHtml($user['first_name']);
$message = $this->messageTextBuilder->buildMessageText($userName, '****');
return $message;
}
}
Jadi, meskipun kelas-kelas telah memperoleh sejumlah dependensi, itu menjadi lebih nyaman untuk menutupi dengan tes atau menggunakan kembali bagian-bagian dari kode. Kami menyingkirkan koneksi di antara mereka, dan kami dapat dengan mudah mengembangkan setiap kelas terpisah secara independen satu sama lain.
PS tentu saja kelas-kelas ini masih jauh dari ideal, tetapi lebih dari itu di lain waktu.