PHP Constructor and Dependencies Shorthand - php

Question

As more and more service oriented PHP is being done these days, I find myself with a lot of PHP files that have this long chunk of code just for initialization. In other languages like C++ or typescript you can do the following without all the duplication. A PHP example:
namespace Test\Controllers;
use Test\Services\AppleService;
use Test\Services\BananaService;
use Test\Services\PearService;
use Test\Services\LemonService;
use Test\Services\PeachService;
class TestController{
protected $appleService;
protected $bananaService;
protected $lemonService;
protected $pearService;
protected $peachService;
public function __construct(
AppleService $appleService,
BananaService $bananaService,
LemonService $lemonService,
PearService $pearService,
PeachService $peachService
){
$this->appleService = $appleService;
$this->bananaService = $bananaService;
$this->lemonService = $lemonService;
$this->pearService = $pearService;
$this->peachService = $peachService;
}
}
A Typescript Example:
module namespace Test.Controllers {
export class TestController{
constructor(
private appleService:Test.Services.AppleService,
private bananaService:Test.Services.BananaService,
private lemonService:Test.Services.LemonService,
private pearService:Test.Services.PearService,
private peachService:Test.Services.PeachService
){}
}
}
Are there better/shorter ways to do the same thing, and/or is any support to make this easier planned for upcoming PHP releases?

Answer 1

There is an alternative, property injection:
use DI\Annotation\Inject;
class TestController
{
/**
* #Inject
* #var AppleService
*/
private $appleService;
/**
* #Inject
* #var BananaService
*/
private $bananaService;
/**
* #Inject
* #var LemonService
*/
private $lemonService;
/**
* #Inject
* #var PearService
*/
private $pearService;
/**
* #Inject
* #var PeachService
*/
private $peachService;
}
Is that shorter, or simpler to write? I'll let you judge. But I love it, I don't end up with a bloated constructor. This is inspired from Java/Spring FYI.
Now this example works with PHP-DI (disclaimer: I work on that), but there may be other DI containers that offer the same functionality.
WARNING: property injection doesn't fit everywhere.
I find it appropriate for controllers (since controllers are not supposed to be reused). Read more here.
I don't think it would be appropriate to use it in services. So that's not the ultimate solution.

Answer 2

This syntactic sugar will finally arrive in PHP 8.0 (November 26, 2020).
By prefixing arguments in the contructor with public, protected or private, they will be copied to and defined as class properties with the same name.
In PHP 8.0 the example of OP can be written as:
namespace Test\Controllers;
use Test\Services\AppleService;
use Test\Services\BananaService;
use Test\Services\PearService;
use Test\Services\LemonService;
use Test\Services\PeachService;
class TestController{
public function __construct(
protected AppleService $appleService,
protected BananaService $bananaService,
protected LemonService $lemonService,
protected PearService $pearService,
protected PeachService $peachService
){
}
}
https://wiki.php.net/rfc/constructor_promotion
https://stitcher.io/blog/constructor-promotion-in-php-8