Coupon code validation

Question

I am trying to modify coupon code functionality. I have got a situation where I am not able to find where a coupon code is validated. I have searched the entire code base. Can anyone point me in right direction?

I am trying to apply Multiple Coupon codes.

Answer 1

Take a look at the class Magento\SalesRule\Model\Utility located at the vendor/magento/module-sales-rule/Model/Utility.php. Coupon code validation starts in the method canProcessRule() where it can mark the rule as invalid if coupon code does not match conditions like usage per customer etc.

Answer 2

The answer to this is quite complex. I will try to provide some hints hopefully i will save somebody's time:

First, coupons (from view cart page) are submitted to Magento\Checkout\Controller\Cart\CouponPost execute() method. Coupons from the checkout page are posted to APIs via ajax, check the actual url in browser's network tab from Tools.

After this, the situation gets complicated :-) It starts from

• vendor/magento/module-sales-rule/Model/RulesApplier.php applyRules()

foreach ($rules as $rule) {
    if (!$this->validatorUtility->canProcessRule($rule, $address)) {
    ...

and canProcessRule() goes to

• vendor/magento/module-sales-rule/Model/Utility.php canProcessRule - method which checks if a rule can be applied for a specific address/quote/customer

The applyRules() method from RulesApplier.php also has the following code:

$rule->getActions()->validate($childItem)

which takes us to

• vendor/magento/module-rule/Model/Condition/Combine.php _isValid(). This method validates the coupon's conditions, and it's the starting point in the validation process. It has this line of code

$validated = $cond->validate($entity);

which actually goes into the next file/method:

• vendor/magento/module-sales-rule/Model/Rule/Condition/Product/Found.php validate(). This method validates individual coupon's conditions and uses the following code

$validated = $cond->validate($item);

which goes to the next file/method:

• vendor/magento/module-sales-rule/Model/Rule/Condition/Product.php validate() which validates a product rule condition. This validates things related to products - like categories and price and through this code

return parent::validate($product);

goes into the MOST IMPORT VALIDATION part which is in the file

• vendor/magento/module-rule/Model/Condition/Product/AbstractProduct.php validate() which validates product attributes.

If you think this can't get more complicated, you're wrong, it goes further down, but you get the idea.