Resolve "Currency Converter API" can not get Currency Rate (issue 24007)

Author: edenduong

app/code/Magento/Directory/Model/Currency/Import/CurrencyConverterApi.php

@@ -7,6 +7,11 @@
 
 namespace Magento\Directory\Model\Currency\Import;
 
+/**
+ * Currency rate import model (From http://free.currencyconverterapi.com/)
+ *
+ * Class \Magento\Directory\Model\Currency\Import\CurrencyConverterApi
+ */
 class CurrencyConverterApi extends AbstractImport
 {
     /**
@@ -46,7 +51,7 @@ public function __construct(
     }
 
     /**
-     * {@inheritdoc}
+     * @inheritdoc
      */
     public function fetchRates()
     {
@@ -75,10 +80,15 @@ public function fetchRates()
     private function convertBatch($data, $currencyFrom, $currenciesTo)
     {
         foreach ($currenciesTo as $to) {
+            //phpcs:ignore Magento2.Functions.DiscouragedFunction
             set_time_limit(0);
             try {
                 $url = str_replace('{{CURRENCY_FROM}}', $currencyFrom, self::CURRENCY_CONVERTER_URL);
                 $url = str_replace('{{CURRENCY_TO}}', $to, $url);
+                $url = $url . '&apiKey=' . $this->scopeConfig->getValue(
+                    'currency/currencyconverterapi/api_key',
+                    \Magento\Store\Model\ScopeInterface::SCOPE_STORE
+                );
                 $response = $this->getServiceResponse($url);
                 if ($currencyFrom == $to) {
                     $data[$currencyFrom][$to] = $this->_numberFormat(1);
@@ -87,9 +97,14 @@ private function convertBatch($data, $currencyFrom, $currenciesTo)
                         $this->_messages[] = __('We can\'t retrieve a rate from %1 for %2.', $url, $to);
                         $data[$currencyFrom][$to] = null;
                     } else {
-                        $data[$currencyFrom][$to] = $this->_numberFormat(
-                            (double)$response[$currencyFrom . '_' . $to]
-                        );
+                        if (isset($response['error']) && $response['error']) {
+                            $this->_messages[] = __($response['error']);
+                            $data[$currencyFrom][$to] = null;
+                        } else {
+                            $data[$currencyFrom][$to] = $this->_numberFormat(
+                                (double)$response[$currencyFrom . '_' . $to]
+                            );
+                        }
                     }
                 }
             } finally {
@@ -137,7 +152,7 @@ private function getServiceResponse($url, $retry = 0)
     }
 
     /**
-     * {@inheritdoc}
+     * @inheritdoc
      */
     protected function _convert($currencyFrom, $currencyTo)
     {

app/code/Magento/Directory/etc/adminhtml/system.xml

@@ -47,7 +47,12 @@
             </group>
             <group id="currencyconverterapi" translate="label" sortOrder="45" showInDefault="1" showInWebsite="0" showInStore="0">
                 <label>Currency Converter API</label>
-                <field id="timeout" translate="label" type="text" sortOrder="0" showInDefault="1" showInWebsite="0" showInStore="0">
+                <field id="api_key" translate="label" type="obscure" sortOrder="0" showInDefault="1" showInWebsite="0" showInStore="0">
+                    <label>API Key</label>
+                    <config_path>currency/currencyconverterapi/api_key</config_path>
+                    <backend_model>Magento\Config\Model\Config\Backend\Encrypted</backend_model>
+                </field>
+                <field id="timeout" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="0" showInStore="0">
                     <label>Connection Timeout in Seconds</label>
                 </field>
             </group>

app/code/Magento/Directory/etc/config.xml

@@ -24,6 +24,7 @@
             </fixerio>
             <currencyconverterapi>
                 <timeout>100</timeout>
+                <api_key backend_model="Magento\Config\Model\Config\Backend\Encrypted" />
             </currencyconverterapi>
             <import>
                 <enabled>0</enabled>