PHP Subclass needs another subclass-CodePudding

I have two subclasses and I want to call a method in one subclass from another. Is the only solution to start chaining my classes in order of dependence? Sorry for the noob PHP question. Basically it's a common scenario to have multiple "base" classes such as an email class in which other subclasses will need access to. So do you just starting chaining them?

// BaseClass.php

require_once("./services/checkout.php");
require_once("./services/email.php");
class Base {
    // ...
}

// checkout.php
    
class checkout extends Base {
    public function onCheckout() {
        // Call send email
        $this->sendEmail($email); // <- How to do this?
    }
}

// email.php

class email extends Base {
    public function sendEmail($email) {
        // Send email
    }
}

CodePudding user response：

I think it's common to have BaseAction or BaseController but not something as generic as BaseClass. It feels more intuitive to have something like:

class Checkout
{
    public function onCheckout(Mailer $mailer)
    {
        $mailer->sendEmail($email);
    }
}

class Mailer
{
    public function sendEmail($email)
    {
        // Send email
    }
}

This is still very rough. You most likely want an interface, injected into checkout constructor, perhaps automagically with some dependency injection library that implements autowiring:

interface MessengerInterface
{
    public function send(string $text): bool
}

class Checkout
{

    private $messenger;
    
    public function __construct(
        MessengerInterface $messenger
    ) {
        $this->messenger = $messenger;
    }

    public function onCheckout()
    {
        $this->messenger->send('Your order blah blah');
    }
}

class Mailer implements MessengerInterface
{
    public function send(string $body): bool
    {
        // Send email
    }
}

CodePudding user response：

Please read Traits in Php. It seem that would be the right thing for your goal:

PHP-Traits (php.org)

PHP-Traits (W3Schools - easier to understand)

I would suggest to reconsider your inheritance, whether it makes sense that E-Mail class and Checkout-Class inherit from the same base class. They should do total different and independent things by their own. If you want to send an e-mail from the checkout-class then try to implement an e-mail class and inject an instance of it to the checkout object.