Composer package - use custom model if exists - laravel

Question

My apologies if this exists already but my search-fu can not find the answer.
I have a composer package, and want to use my model ONLY IF an existing model doesn't exist (or extend the custom model), but I can't seem to figure out how to specify the "use" command properly inside my composer model. Since I won't know the name of the "app" using the package, I can't extend it.
<?php
namespace MyComposer\Package\Models;
use Illuminate\Database\Eloquent\Model;
class MyPackageModel extends Model
{
If I put it as a config option, I can't use that in the extends i.e class MyPackageModel extends config('custom_model_name')
I had thought I should do the check in the ServiceProvider but I can't seem to find the right code to register the proper model name to use in there.
Thanks.

Answer 1

I've done something similar to this before, I believe. But my approach was slightly different. See if it makes sense:
Create a base class in your own package. This will be the fallback
model which will be used if the "local" package (the one consuming
your package) doesn't have it's own version of it;
Create a config file which states which model will be used. The default is the model inside your own package (i.e. the fallback);
After installing and setting up your package, if a user does nothing they will automatically have your base model available. If they wish to override your base model with a custom local version, they can simply extend your base model and alter the model to be used in their config file.
I've also found that sometimes it's useful for the base model to 1) implement an interface that can be checked in your package's logic without relying on a specific class (which, after all, is meant to be overridden, right?); and 2) have most of it's logic inside a trait which the "local" model can use without ever having to extend your model (crucial if the local model already extends some other class for whatever reason).
How you approach the code would very much depend what you plan to do with that model. Say, for example, you have a supporting class that creates media entries in your database. Here's your packages model:
<?php
namespace Namespace\Package;
class Media
{
//...
}
And here's the default config:
<?php
return [
'model' => \Namespace\Package\Media::class,
];
And here's a sample manipulation, where you actually account for the local app to override your own model:
<?php
namespace Namespace\Package;
class MediaManager
{
protected function getModel()
{
$model = config('package.model');
return new $model;
}
public function createMedia($attributes = [])
{
$media = $this->getModel($attributes);
$media->save();
return $media;
}
}
That is to say, you never reference any Media model literally. You do your manipulations via the MediaManager. Of course the logic is very simplistic, but hopefully it's enough to get the bigger picture.