Laravel how to add a custom function in an Eloquent model?

Question

I have a Product model

class Product extends Model {     ...      public function prices()     {         return $this->hasMany('App\Price');     }      ... } 

I want to add a function which will return the lowest price, and in controller I can get the value using:

Product::find(1)->lowest; 

I added this in Product model:

public function lowest() {     return $this->prices->min('price'); } 

but I got an error saying:

Relationship method must return an object of type Illuminate\Database\Eloquent\Relations\Relation 

And if I use Product::find(1)->lowest();, it will work. Is it possible to get Product::find(1)->lowest; to work?

Any help would be appreciated.

Answer 1

When you try to access a function in the model as a variable, laravel assumes you're trying to retrieve a related model. They call them dynamic properties. What you need instead is a custom attribute.

Before Laravel 9

Laravel 6 docs: https://laravel.com/docs/6.x/eloquent-mutators

add following method to your model:

public function getLowestAttribute() {     //do whatever you want to do     return 'lowest price'; } 

Now you should be able to access it like this:

Product::find(1)->lowest; 

EDIT: New in Laravel 9

Laravel 9 offers a new way of dealing with attributes:

Docs: https://laravel.com/docs/9.x/eloquent-mutators#accessors-and-mutators

// use Illuminate\Database\Eloquent\Casts\Attribute;  public function lowest(): Attribute {      return new Attribute(         get: function( $originalValue ){          //do whatever you want to do          //return $modifiedValue;       });       /**       * Or alternatively:-       *       * return Attribute::get( function( $originalValue ){       *    // do whatever you want to do       *    // return $modifiedValue;       * });       */ }