Accessing Silex Application class from other classes; how to inject? - php

Question

I'm currently working on my first Silex (2.0) project. I have some Pheasant models defined, which I can access from within my controller:
// it is used both static
$p = \Model\Post::oneById(3);
// .. and with an instance
$p = new \Model\Post;
$p->title = 'foobar';
$p->save();
Now, in some cases I'd like to access the Application class within my model. For example, to check if we're running in debug mode (or not). Right now:
public function beforeSave() {
global $app;
if($app['debug']) {
// ...
}
}
But that doesn't feel like Silex. So I figured I need some kind of thing that'll automatically inject the $app class to my models:
class PheasantModelReflector {
protected $app;
public function __construct(\Silex\Application $app) {
$this->app = $app;
}
public function __get($className) {
$r = (new ReflectionClass(sprintf('Model\%s', $className)))->newInstance();
$r->__invoke($this->app);
return $r;
}
}
$app['model'] = function ($app) {
return new PheasantModelReflector($app);
};
This works to a certain level, but always returns a new instance of the Post model when called like $app['model']->Post.
Is there any way to fix this?

Answer 1

Without having worked with Pheasant, I may try to create a service factory that injects the $app (or the $debug var) into your entity class like so (one problem here is that your entity must extend \Pheasant\DomainObject and you can't override the constructor as it's marked as final):
<?php
// in the example below I inject the whole $app, if you only need the
// debug var, inject only that, injecting the whole $app may
// tempt you to use it as a service locator
// creating a new instance
$app['model_post_factory'] = $app->factory(function ($app) {
$post = new \Model\Post();
$post->setApp($app);
return $post;
});
$post = $app['model_post_factory'];
// getting an instance by ID, here it gets a little tricky
$app['model_post_static_factory'] = function($app, $id) {
$post = \Model\Post::oneById($id);
$post->setApp($app);
return $post;
}
$postById = $app->raw('model_post_static_factory');
$post = $postById($app, $id); // $id comes from somewhere else
// depending on the PHP version you may try directly:
// $post = $app->raw('model_post_static_factory')($app, $id);
The problem with the static method is passing the id parameter. You can import into the factory scope the $id from the outside scope using the use keyword, but IMHO this is too magic (though I don't quite like the alternative either). There may be some more elegant way, but I can't think of right now.

Answer 2

To avoid to generate a new instance of model everytime you need to create a shared service (http://silex.sensiolabs.org/doc/services.html).
For example:
$app['model'] = $app->share(function () {
return new PheasantModelReflector();
});
Anyway inject $app is not necessarily a good idea, maybe you can just inject the dependency every object has? Something like:
new \Model\Post($app['debug']);