PHP Replacing static methods in Entities, best practices - php

Question

<?php
class Entity {
/**
* #var array|stdClass|Collection|string
**/
private $mixed;
public function getMixedAsPhpArray(array $filter) {
return EntityHelper::toPhpArray($this->mixed, $filter);
}
}
Given the above class, how would you remove the static call to EntityHelper::toPhpArray assuming $mixed could by any of the types in the PHPDoc Block? (This is just a simplified example of an issue I'm facing where I have a function to take "dirty in and clean out") (I cannot add it to the Entity as many Entities need this function and cannot extend from an Abstrart Entity with this method as they already extend various others).
I'm using Symfony and thought of DI in the helper but replacing all new Entity with a call to the service container would be a bad (and slow) idea. Another idea would be to return the dirty output and use a service to clean and filter it but I also think that's a bad idea as it takes all the data from the Entity out into the Application then into the Service when I think it should happen in one go and remove mistakes (and maybe memory usage...).

Answer 1

The best solution will depend on your application, but one method you might use is to put your helper code in a trait:
<?php
trait ArrayCleaner {
public function toPhpArray($dataToFilter, $filterArray) {
// ... your code here
}
}
class Entity {
use ArrayCleaner;
/**
* #var array|stdClass|Collection|string
**/
private $mixed;
public function getMixedAsPhpArray(array $filter) {
return $this->toPhpArray($this->mixed, $filter);
}
}
http://php.net/manual/en/language.oop5.traits.php

Answer 2

Well, you could do this with a trait.
trait EntityHelperTrait
{
private function toPhpArray($value, $filter) {
// body of method
}
}
class Entity
{
use EntityHelperTrait;
/**
* #var array|stdClass|Collection|string
**/
private $mixed;
public function getMixedAsPhpArray(array $filter) {
return $this->toPhpArray($this->mixed, $filter);
}
}
But based on your (admittedly simplified) example, you're mixing responsibilities. The job of type conversion, which is what this essentially is, should belong somewhere else, not baked into the Entity class itself.
I think it's totally fine to let the Entity return the "dirty" output for another component to filter/clean/whatever.