Migrating Shipping Extension for Magento 1.9 to Magento 2.2 - magento

Question

I am trying to migrate a custom magento 1.9 extension to magento 2.2. I have done a lot of searching and can't find information on the use case I'm trying to migrate. I originally followed this tutorial for the 1.9 extension. I understand there is a tool to help port extensions, but I am trying to do this manually as I couldn't get that tool to function for me.
The custom shipping extension would run each time the shopping cart was updated to calculate a custom shipping rate. The goal is to recreate this extension in magento 2.2 such that each time the shopping cart is opened or updated it will run and calculate a shipping cost which will then propagate through the checkout process.
Below is an overview of the magento 1.9 extension. Any advice on how to translate this to magento 2.2?
/app/etc/modules/Extensions_Shipper.xml
<?xml version="1.0"?>
<config>
<modules>
<Extensions_Shipper>
<active>true</active>
<codePool>local</codePool>
<depends>
<Mage_Shipping />
</depends>
</Extensions_Shipper>
</modules>
/app/code/local/Extensions/Shipper/etc/config.xml
<?xml version="1.0" encoding="UTF-8"?>
<config>
<modules>
<Extensions_Shipper>
<module>0.0.1</module>
</Extensions_Shipper>
</modules>
<global>
<models>
<extensions_shipper>
<class>Extensions_Shipper_Model</class>
</extensions_shipper>
</models>
</global>
<default>
<carriers>
<extensions_shipper>
<active>1</active>
<model>extensions_shipper/carrier</model>
<title>Shipping Options</title>
<sort_order>10</sort_order>
<sallowspecific>0</sallowspecific>
</extensions_shipper>
</carriers>
</default>
/app/code/local/Extensions/Shipper/Model/Carrier.php
<?php
class Extensions_Shipper_Model_Carrier extends Mage_Shipping_Model_Carrier_Abstract implements Mage_Shipping_Model_Carrier_Interface
{
public function collectRates(Mage_Shipping_Model_Rate_Request $request)
{
//Are there magento 2.2 equivalence for the following?
$addressInfo = Mage::getSingleton('checkout/session')->getQuote()->getShippingAddress()->getData();
$result = Mage::getModel('shipping/rate_result');
$items = Mage::getSingleton('checkout/session')->getQuote()->getAllItems();
$currentItem = Mage::getModel('catalog/product')->load($items[$itemsArray[$i]]->getProduct()->getId());
Mage::getSingleton('core/session')->addNotice('some text');
//$result = some calculations for shipping rate
return $result;
}
public function getAllowedMethods()
{
return array();
}
}

Answer 1

You can create an event observer on the checkout_cart_add_product_complete event to execute the logic to update the shipping costs.
namespace MyCompany\MyModule\Observer;
use Magento\Framework\Event\ObserverInterface;
class MyObserver implements ObserverInterface
{
public function __construct()
{
//Observer initialization code...
//You can use dependency injection to get any class this observer may need.
}
public function execute(\Magento\Framework\Event\Observer $observer)
{
//Observer execution code...
}
}
Subscribe to the event in events.xml:
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
<event name="my_module_event_before">
<observer name="myObserverName" instance="MyCompany\MyModule\Observer\MyObserver" />
</event>
<event name="my_module_event_after">
<observer name="myObserverName" instance="MyCompany\MyModule\Observer\AnotherObserver" />
</event>
</config>
See Magento docs on events and observers: http://devdocs.magento.com/guides/v2.0/extension-dev-guide/events-and-observers.html
For a list of all Magento 2.2 events, see: https://cyrillschumacher.com/magento-2.2-list-of-all-dispatched-events/