Add attribute to eloquent model

Question

I would like to calculate the value of an attribute in it's model, but can not get the data I need.

class Product extends Model
{

    protected $appends = ['lowest_price'];

    public function shops(){
        return $this->belongsToMany('App\Shop')->withPivot('price','url');
    }

    public function type(){
        return $this->belongsTo('App\Type');
    }

    public function getLowestPriceAttribute()                      <-----------------------------
    {
        $lowest_price = 0;
        foreach($this->shops() as $shop) {
            if($lowest_price > $shop->pivot->price) {
                $lowest_price = $shop->pivot->price;
            }
        }
        return $lowest_price;
    }
}

$this->shops() does not seem to load all the data I need to do the calculations.

In my view I am able to iterate over the product's shop like so:

@foreach($shops as $shop)   
    <tr>
        <a href="{{ $shop->pivot->url }}" target="_blank">      
            <td>{{ $shop->name }}</td>
            <td>{{ $shop->pivot->price }}EUR</td>
        </a>        
    </tr>
@endforeach

If this is not possible would the best alterrnative be to do the calculations in the view itself instead of the model?

Answer 1

You should be able to do that in an accessor function for sure. I think the problem that you are having is simpler than you think.

$shops in your view is probably a collection, but $this->shops() returns a Query Builder instance.. so try changing this line in the function:

foreach($this->shops() as $shop) {

With this:

foreach($this->shops as $shop) {

And let me know if it works. Without () the shops will be a collection.