Modifying a PHP class file or stub programmatically - php

Question

Given a PSR-2 compliant PHP class file (or stub)
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Car extends Model
{
/**
* The attributes that are mass assignable.
*
* #var array
*/
protected $fillable = [
//
];
/**
* The attributes that should be hidden for arrays.
*
* #var array
*/
protected $hidden = [
//
];
}
Is there some tool to easily parse and modify it?
In the best of worlds with a fluent API, maybe something like:
PhpClass::make(".../Car.php")
->setNamespace("Some/New/Namespace")
->use("Some\Dependency")
->addMethod($newFunctionBody)
Im aware this might be a naive example, but how close to such a tool is there out there? By tool I mean something I can pull in as a dependency preferably via composer.
Right now I have a somewhat working solution using placeholders and regex but it starts to grow out of control with many edge cases. Therefore im thinking I might need to actually interpret the PHP.

Answer 1

Componere
Componere is a PHP 7 extension, available on pecl and documented in the PHP manual ...
The code below registers the definition in the class entry table:
<?php
/* just making the example standalone */
class Model {}
class Car extends Model {
public function something() {}
}
trait SaysVroomVroomWhenPoked {
public function poke() {
return "Vroom Vroom";
}
}
$def = new \Componere\Definition(Some\Place\Car::class, Car::class);
$def->addTrait(SaysVroomVroomWhenPoked::class);
$def->addMethod("newMethod", new \Componere\Method(function(){
return 42;
}));
$def->register();
$car = new \Some\Place\Car();
printf("%s and %d\n", $car->poke(), $car->newMethod());
?>
Registering the class in the entry table may be desirable in some cases, it's effects are application wide for the life of the request.
The code below patches a particular instance of an object with the required features:
<?php
/* just making the example standalone */
class Model {}
class Car extends Model {
public function something() {}
}
trait SaysVroomVroomWhenPoked {
public function poke() {
return "Vroom Vroom";
}
}
function accept(Car $car) {
$patch = new \Componere\Patch($car);
$patch->addTrait(SaysVroomVroomWhenPoked::class);
$patch->addMethod("newMethod", new \Componere\Method(function(){
return 42;
}));
$patch->apply();
printf("%s and %d\n", $car->poke(), $car->newMethod());
}
$car = new Car();
accept($car);
var_dump(method_exists($car, "newMethod")); # false
?>
Note that doing this everywhere is much less efficient than changing the definition, but it's side effects disappear when the accept function returns.
http://php.net/componere
Note: it has a fluid interface, but for the purposes of clarity I did not use it here ...
Edit:
I just noticed your comment expressing an interest in pre-processing code, or possibly using anonymous classes, and not runtime manipulation. Using anonymous classes is an excellent idea, but I don't think you need an example of that ...
Full disclosure: I wrote Componere, and I wrote the implementation of anonymous classes for PHP ...
Anything I say to dissuade you from pre-processing is probably going to be pretty empty now ...

Answer 2

I built a Laravel package for this use case: https://github.com/ajthinking/php-file-manipulator

Answer 3

There may actually be a way to do this. The concept you're looking for is called 'monkey patching'. I really wouldn't recommend opening that can of worms if at all possible, it's inherently hacky. But I think there are some PHP packages that offer it. You might also want to look into Php7's concept of 'anonymous classes'. Perhaps coupled with using Reflection to parse the class you're trying to effectively alter, you could build an anonymous class to replicate it, use Reflection on it to get the raw code therein, write it to a temp file, and somehow swap it out for the original in the auto-loader's namespace=>filepath list at runtime.
I can't promise any of that will work though, and can promise it'd be a headache. But if you're looking to tinker, there's some food for thought. If you do get it working, please post it here, I wouldn't mind seeing it. Good luck.