How does magento 2 calculate price of configurable products?

Question

I am a magento 2 starter with much experience in magento 1. I can't find the relevant scripts which are used to calculate the price for configurable products.

I need a basic guide on how the configuration works please so that I can modify it.

E.g. I need to add a customise-able option with title Length and the price should change based on it's value.

So if the price is $1000 and 1000 millimetres is set then the price should be $1000,

if 500 millimetres is set, then the price should be 500$.

If 2000 millimetres is set then the price should be 2000$ and so on...

price = (price * (length / 1000))

Where do I have to add this logic?

Answer 1

Magento 2 config product price is different with Magento 1.

• In Magento 1 the price is calculated based on super attributes.

• In Magento 2 the price is taken from child product.

In your case, we have two methods:

1. Using Magento Backend: Generate the children with option Apply unique prices by attribute to each SKU, enter fixed price to each value of length attribute.

2. Using Magento source code: create a 3rd module and override getValue() function in /vendor/magento/module-catalog/Pricing/Price/BasePrice.php class using di.xml. The code should be:

   public function getValue()
   {
       if ($this->value === null) {
           $this->value = false;
           foreach ($this->priceInfo->getPrices() as $price) {
               if ($price instanceof BasePriceProviderInterface && $price->getValue() !== false) {
                   $this->value = min($price->getValue(), $this->value ?: $price->getValue());
               }
           }
       }
       $objectManager = \Magento\Framework\App\ObjectManager::getInstance();
       $product = $objectManager->create('Magento\Catalog\Model\Product')->load($this->product->getId());
       if ($product) {
           $length = $product->getResource()->getAttribute('length')->getFrontend()->getValue($product);
           if ($length) {
               $this->value = $this->value * ($length / 1000);
           }
       }
       return $this->value;
   }
   

   Tested in Magento 2.3.0

That's it.