ConfigChangeObserver.php

<?php

namespace BobGroup\BobGo\Observer;

use Magento\Framework\Event\Observer;
use Magento\Framework\Event\ObserverInterface;
use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Framework\HTTP\Client\Curl;

class ConfigChangeObserver implements ObserverInterface
{
    protected $scopeConfig;
    protected $curl;

    public function __construct(
        ScopeConfigInterface $scopeConfig,
        Curl $curl
    ) {
        $this->scopeConfig = $scopeConfig;
        $this->curl = $curl;
    }

    public function execute(Observer $observer)
    {
        $sectionId = $observer->getEvent()->getSection();

        // Ensure we're working with the 'carriers' section
        if ($sectionId === 'carriers') {
            $isEnabled = $this->scopeConfig->getValue('carriers/bobgo/active', \Magento\Store\Model\ScopeInterface::SCOPE_STORE);

            // Check if the extension is enabled
            if ($isEnabled) {
                $url = 'https://api.dev.bobgo.co.za/rates-at-checkout/magento';

                // Prepare the payload
                $payload = json_encode([
                    "identifier" => "woodemo3.bobgo.co.za",
                    "rate" => [
                        "origin" => [
                            "country" => "ZA",
                            "postal_code" => "0181",
                            "province" => "GP",
                            "city" => "Pretoria",
                            "name" => null,
                            "address1" => "125 Dallas Avenue",
                            "address2" => "Newlands",
                            "address3" => null,
                            "phone" => "",
                            "fax" => "",
                            "email" => null,
                            "address_type" => null,
                            "company_name" => ""
                        ],
                        "destination" => [
                            "country" => "ZA",
                            "postal_code" => "0181",
                            "province" => "GP",
                            "city" => "Pretoria",
                            "name" => null,
                            "address1" => null,
                            "address2" => "",
                            "address3" => null,
                            "phone" => "",
                            "fax" => "",
                            "email" => null,
                            "address_type" => null,
                            "company_name" => "",
                            "shipping_suburb" => "Elarduspark"
                        ],
                        "currency" => "ZAR",