How do I set PHP class properties with construct() arguments automatically? - php

Question

Does anyone know of an efficient technique in PHP to auto assign class parameters with identically named __construct() method arguments?
For instance, I've always thought it was highly inefficient to do something like the following:
<?php
class Foo
{
protected $bar;
protected $baz;
public function __construct($bar, $baz)
{
$this->bar = $bar;
$this->baz = $baz;
}
}
I'm wondering if there's a better/more efficient way/magic method to auto-assign class properties with identically named method parameters.
Thanks,
Steve

Answer 1

PHP 8
Constructor Promotion
function __construct(public $bar, public $baz) {}
PHP 5
function _promote(&$o) {
$m = debug_backtrace(0, 2)[1];
$ref = new ReflectionMethod($m['class'], $m['function']);
foreach($ref->getParameters() as $i=>$p) {
$o->{$p->name} = $m['args'][$i] ?? $p->getDefaultValue();
}
}
class Foo {
function __construct($bar, $baz) {
_promote($this);
}
}

Answer 2

I think this way is a pretty generally accepted way to do it, although you could make getters and setters. Or, if you're looking for magic methods in php: http://php.net/manual/en/language.oop5.magic.php

Answer 3

Not in a constructor. You can always wrap your properties into an array, instead, and only have a single property that needs to be set:
<?php
class SomeClass
{
protected $data = [];
public function __construct(array $data = [])
{
$this->data = $data;
}
public function getData()
{
return $this->data;
}
}
$params = ['bar' => 'bar', 'baz' => 'baz'];
$someClass = new SomeClass($params);
echo $someClass->getData()['bar'] . PHP_EOL;
There is the magic method __set, but it is only called when attempting to write data to inaccessible properties:
<?php
class SomeClass
{
protected $data = [];
public function __construct(array $data = [])
{
$this->data = $data;
}
public function __set($name, $value)
{
$this->data[$name] = $value;
}
public function __get($name)
{
if(isset($this->data[$name])) {
return $this->data[$name];
}
return null;
}
}
$class = new SomeClass;
$class->bar = 'bar';
$class->baz = 'baz';
echo $class->bar . PHP_EOL . $class->baz . PHP_EOL;
If your class is starting to have a lot of parameters being passed in to the constructor, it may be a sign that your class is getting too big and trying to do too much. A refactoring may be in order.