Coupon Recipe - PHP

charge.php

Managing coupons on the server
----------------

<?php

$private_key = 'sk_test_xxxxx';

$amount = 500;
$final_amount = '';

$coupon = $_POST['couponCode'];

function get_discount($coupon){
  $coupons = [
    'coupon1' => 0.15,
    'coupon2' => 0.25
    ];
  
  if(isset($coupons[$coupon])){
    return $coupon[$coupon];
  }else{
    return false;
  }
}

if(!empty($coupon)){
  $discount = get_discount($coupon);
  
  if(!discount){
    echo 'Error: Coupon is invalid.';
  }else{
    $discount_amount = $amount * $discount;
    $final_amount = $amount - $discount_amount;
    
    $metadata = [
      'coupon' => $coupon,
      'amount' => $discount_amount
      ];
  }
}

try{
  
  $customer = \Stripe\Customer::create(array(
    'email' => $_POST['stripeEmail'],
    'source' => $_POST['stripeToken']
    ));
  
  $charge = \Stripe\Charge::create(array(
    'amount' => $final_amount,
    'customer' => $customer->id,
    'description' => 'PHP Example',
    'metadata' => $metadata,
    'currency' => 'usd'
    ));
  
}catch(\Exception $e){
  //Var dump during DEV only; switch to something like error_log($e) later.
  var_dump($e);
}

new.php

Adding a form field
-------------------

<?php

$public_key = 'pk_test_xxxxxx';
$charge_endpoint = '/charge.php';

?>

<form action="<?= $charge_endpoint ?>" method="POST">
 <p>
    <label class="amount">
      <span>Amount: $5.00</span>
    </label>
  </p>
  
  <p>
    <label for="couponCode">Coupon</label><input type="text" name="couponCode" id="couponCode" />
  </p>
  
  <script src="https://checkout.stripe.com/checkout.js" class="stripe-button"
          data-key="<?= $public_key ?>"
          data-description="Your Purchase"
          data-locale="auto"></script>
</form>