php - L4.2 Extend/override Cashier to add Tax feature -

i using laravel 4.2 cashier , need modify protected function buildpayload() don't want directly in vendor file break code when composer update... how should proceed override function own logic ?

i use cashier in 1 of controller doing:

$user->subscription('testplan')                     ->create(input::get('stripetoken'), [                         'email' => 'email@email.com,                     ]); 

but want add withtax() parameters... so:

$user->subscription('testplan')                         ->withtax(10)                         ->create(input::get('stripetoken'), [                             'email' => 'email@email.com,                         ]); 

i know how directly in stripegateway.php file it's bad practice...

i know need add:

protected $taxpercent = 0;      public function withtax($tax)     {         $this->taxpercent = $tax;          return $this;     }      protected function buildpayload()     {         $payload = [             'plan' => $this->plan, 'prorate' => $this->prorate,             'quantity' => $this->quantity, 'trial_end' => $this->gettrialendforupdate(),             'tax_percent' => $this->taxpercent,         ];          return $payload;     } 

what don't know how add code not directly in cashier original file.

you add gettaxpercent method in user model , calculate taxes well.laravel docs

sadly there's no option extend stripegateway class hard coded in billable trait,what can change functions -

public function charge($amount, array $options = []) { return (new stripegateway($this))->charge($amount, $options); } public function subscription($plan = null) { return new stripegateway($this, $plan); } in user class,the problem here can never know change in billable,they might change name of functions , add few more uses stripegateway , wouldn't know until bugs arrive.

the first option better wont need mention withtax method each time.