Added frankfurter.dev API provider

Author: jbtronics

src/Service/Frankfurter.php

@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+
+namespace Exchanger\Service;
+
+use Exchanger\Contract\ExchangeRate;
+use Exchanger\Contract\ExchangeRateQuery;
+use Exchanger\Contract\HistoricalExchangeRateQuery as HistoricalExchangeRateQueryContract;
+use Exchanger\Exception\UnsupportedCurrencyPairException;
+
+/**
+ * Uses the free API at https://frankfurter.dev/
+ */
+final class Frankfurter extends HttpService
+{
+
+    private const BASE_URL = "https://api.frankfurter.dev/v1/";
+    private const SUPPORTED_CURRENCIES = [
+        'AUD', 'BGN', 'BRL', 'CAD', 'CHF', 'CNY', 'CZK', 'DKK', 'EUR',
+        'GBP', 'HKD', 'HUF', 'IDR', 'ILS', 'INR', 'ISK', 'JPY',
+        'KRW', 'MXN', 'MYR', 'NOK', 'NZD', 'PHP', 'PLN', 'RON',
+        'SEK', 'SGD', 'THB', 'TRY', 'USD', 'ZAR'
+    ];
+
+    public function supportQuery(ExchangeRateQuery $exchangeQuery): bool
+    {
+        $currencyPair = $exchangeQuery->getCurrencyPair();
+        return in_array($currencyPair->getBaseCurrency(), self::SUPPORTED_CURRENCIES) &&
+               in_array($currencyPair->getQuoteCurrency(), self::SUPPORTED_CURRENCIES);
+    }
+
+    public function getName(): string
+    {
+        return 'frankfurter';
+    }
+
+    public function getExchangeRate(ExchangeRateQuery $exchangeQuery): ExchangeRate
+    {
+        $currencyPair = $exchangeQuery->getCurrencyPair();
+        $base = $currencyPair->getBaseCurrency();
+        $quote = $currencyPair->getQuoteCurrency();
+
+        if ($exchangeQuery instanceof HistoricalExchangeRateQueryContract) {
+            $date = $exchangeQuery->getDate()->format('Y-m-d');
+            $url = self::BASE_URL . "{$date}?base={$base}&symbols={$quote}";
+        } else {
+            $url = self::BASE_URL . "latest?base={$base}&symbols={$quote}";
+        }
+
+        $content = $this->request($url);
+        $data = json_decode($content, true);
+
+        if (!isset($data['rates'][$quote])) {
+            throw new UnsupportedCurrencyPairException($currencyPair, $this);
+        }
+
+        $rate = (float)$data['rates'][$quote];
+        $date = new \DateTime($data['date']);
+
+        return $this->createRate($currencyPair, $rate, $date);
+    }
+}

src/Service/Registry.php

@@ -55,7 +55,8 @@ public static function getServices(): array
             'exchangeratehost' => ExchangerateHost::class,
             'apilayer_fixer' => ApiLayer\Fixer::class,
             'apilayer_currency_data' => ApiLayer\CurrencyData::class,
-            'apilayer_exchange_rates_data' => ApiLayer\ExchangeRatesData::class
+            'apilayer_exchange_rates_data' => ApiLayer\ExchangeRatesData::class,
+            'frankfurter' => Frankfurter::class,
         ];
     }
 }

tests/Fixtures/Service/Frankfurter/EUR_USD.json

@@ -0,0 +1,8 @@
+{
+    "amount": 1,
+    "base": "EUR",
+    "date": "2025-09-05",
+    "rates": {
+        "USD": 1.1697
+    }
+}

tests/Fixtures/Service/Frankfurter/EUR_USD_historic.json

@@ -0,0 +1,8 @@
+{
+    "amount": 1,
+    "base": "EUR",
+    "date": "1999-04-13",
+    "rates": {
+        "USD": 1.0765
+    }
+}

tests/Tests/Service/FrankfurterTest.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace Exchanger\Tests\Service;
+
+use Exchanger\CurrencyPair;
+use Exchanger\ExchangeRateQuery;
+use Exchanger\HistoricalExchangeRateQuery;
+use Exchanger\Service\Frankfurter;
+
+class FrankfurterTest extends ServiceTestCase
+{
+    public function testItHasAName(): void
+    {
+        $service = new Frankfurter($this->createMock('Http\Client\HttpClient'));
+
+        $this->assertSame('frankfurter', $service->getName());
+    }
+
+    public function testFetchLatestRate(): void
+    {
+        $url = 'https://api.frankfurter.dev/v1/latest?base=EUR&symbols=USD';
+        $content = file_get_contents(__DIR__.'/../../Fixtures/Service/Frankfurter/EUR_USD.json');
+
+        $pair = CurrencyPair::createFromString('EUR/USD');
+        $service = new Frankfurter($this->getHttpAdapterMock($url, $content));
+
+        $rate = $service->getExchangeRate(new ExchangeRateQuery($pair));
+
+        $this->assertSame(1.1697, $rate->getValue());
+        $this->assertEquals(new \DateTime('2025-09-05'), $rate->getDate());
+    }
+
+    public function testFetchHistoricRate(): void
+    {
+        $url = 'https://api.frankfurter.dev/v1/1999-04-13?base=EUR&symbols=USD';
+        $content = file_get_contents(__DIR__.'/../../Fixtures/Service/Frankfurter/EUR_USD_historic.json');
+
+        $pair = CurrencyPair::createFromString('EUR/USD');
+        $service = new Frankfurter($this->getHttpAdapterMock($url, $content));
+
+        $rate = $service->getExchangeRate(new HistoricalExchangeRateQuery($pair, new \DateTime("1999-04-13")));
+
+        $this->assertSame(1.0765, $rate->getValue());
+        $this->assertEquals(new \DateTime('1999-04-13'), $rate->getDate());
+    }
+}