laravel 5 how to add to $with / $appends fields in child model class

Question

I have several models which share some common functionality (due to their polymorphism) which I'd like to pull into a ResourceContentModel class (or even a trait).

The ResourceContentModel class would extend the eloquent Model class and my individual models would then extend ResourceContentModel.

My question is around the model fields like $with, $appends and $touches. If I make use of these for any of the common functionality in ResourceContentModel, then when I redefine them in my child model class, it overwrites the values I've set in my parent class.

Looking for some suggestions for a clean way around this?

For example:

class ResourceContentModel extends Model
{
    protected $with = ['resource']
    protected $appends = ['visibility']

    public function resource()
    {
        return $this->morphOne(Resource::class, 'content');
    }

    public function getVisibilityAttribute()
    {
        return $this->resource->getPermissionScope(Permission::RESOURCE_VIEW);
    }
}

class Photo extends ResourceContentModel
{
    protected $with = ['someRelationship']
    protected $appends = ['some_other_property']

    THESE ARE A PROBLEM AS I LOSE THE VALUES IN ResourceContentModel
}

I'm after a clean way to do this so the child classes aren't overly changed by the fact I've slotted in an extra class in the hierarchy to gather the common code.

Answer 1

No idea if this will work...

class Photo extends ResourceContentModel
{
    public function __construct($attributes = [])
    {
        parent::__construct($attributes);
        $this->with = array_merge(['someRelationship'], parent::$this->with);
    }
}

Or perhaps add a method on ResourceContentModel to access the property.

class ResourceContentModel extends Model
{
    public function getParentWith()
    {
        return $this->with;
    }
}

then

class Photo extends ResourceContentModel
{
    public function __construct($attributes = [])
    {
        parent::__construct($attributes);
        $this->with = array_merge(['someRelationship'], parent::getParentWith());
    }
}

EDIT

In the constructor of the 3rd snippet,

$this->with = array_merge(['someRelationship'], parent->getParentWith());

needed to be

$this->with = array_merge(['someRelationship'], parent::getParentWith());