README

A PHP SDK for the Currency Exchange API. This package provides an easy-to-use interface to fetch current and historical exchange rates with built-in fallback support.

Features

• 🚀 Easy to use static methods
• 💪 Built-in fallback support between JSDelivr and Cloudflare endpoints
• 📅 Support for historical exchange rates
• 🔄 Automatic retry with minified and regular JSON formats
• ⚡ Fast and reliable with multiple CDN options
• 🛠 Configurable endpoint preferences
• 🔍 Comprehensive error handling
• 💾 PSR-16 compatible caching support
• ⚙️ Customizable HTTP client configuration

Installation

Install the package via Composer:

composer require php-core/exchange-sdk

Quick Start

use PHPCore\ExchangeSDK\Exchange;

// Get latest USD rates
$usdRates = Exchange::getLatestRates('usd');

// Get EUR/USD rate
$eurUsdRate = Exchange::getLatestRate('eur', 'usd');

// Get historical rates
$historicalRates = Exchange::getHistoricalRates('2024-03-06', 'usd');

Usage Examples

Getting Latest Exchange Rates

use PHPCore\ExchangeSDK\Exchange;

// Get all rates for USD
$usdRates = Exchange::getLatestRates('usd');
// Returns: ['date' => '2024-03-06', 'usd' => ['eur' => 0.85, 'gbp' => 0.73, ...]]

// Get specific currency pair rate
$eurUsdRate = Exchange::getLatestRate('eur', 'usd');
// Returns: 1.18 (float)

Getting Historical Rates

// Get historical rates for a specific date
$historicalRates = Exchange::getHistoricalRates('2024-03-06', 'usd');
// Returns: ['date' => '2024-03-06', 'usd' => ['eur' => 0.84, ...]]

// Get historical rate for a specific currency pair
$historicalEurUsd = Exchange::getHistoricalRate('2024-03-06', 'eur', 'usd');
// Returns: 1.08854773 (float)

Configuring Endpoints

// Set Cloudflare as the preferred endpoint globally
Exchange::setPreferredEndpoint(Exchange::ENDPOINT_CLOUDFLARE);

// Or use a specific endpoint for a single call
$rates = Exchange::getLatestRates('usd', Exchange::ENDPOINT_JSDELIVR);

Caching Support

The SDK supports PSR-16 Simple Cache for storing exchange rates. By default, it uses Symfony's FilesystemAdapter.

Default Cache Configuration

// Initialize with default filesystem cache (24-hour TTL)
Exchange::initCache();

// Rates will be automatically cached
$rates = Exchange::getLatestRates('usd');

Custom Cache Configuration

use Symfony\Component\Cache\Adapter\FilesystemAdapter;
use Symfony\Component\Cache\Psr16Cache;

// Create a custom filesystem cache
$filesystemAdapter = new FilesystemAdapter(
    'exchange-rates',    // namespace
    3600,               // TTL (1 hour)
    '/path/to/cache'    // custom directory
);
$cache = new Psr16Cache($filesystemAdapter);

// Initialize SDK with custom cache
Exchange::initCache($cache);

Using Redis Cache

use Symfony\Component\Cache\Adapter\RedisAdapter;
use Symfony\Component\Cache\Psr16Cache;

$redis = RedisAdapter::createConnection('redis://localhost');
$cache = new Psr16Cache(new RedisAdapter($redis));

Exchange::initCache($cache, 3600); // Cache for 1 hour

Cache Management

// Clear the cache
Exchange::clearCache();

Custom HTTP Client Configuration

use GuzzleHttp\Client;

// Configure custom Guzzle client
$client = new Client([
    'timeout' => 15,
    'connect_timeout' => 10,
    'headers' => [
        'User-Agent' => 'MyApp/1.0'
    ]
]);

Exchange::setClient($client);

Available Methods

Main Methods

• getLatestRates(string $baseCurrency, ?string $endpoint = null): ?array
• getHistoricalRates(string $date, string $baseCurrency, ?string $endpoint = null): ?array
• getLatestRate(string $fromCurrency, string $toCurrency, ?string $endpoint = null): ?float
• getHistoricalRate(string $date, string $fromCurrency, string $toCurrency, ?string $endpoint = null): ?float

Configuration Methods

• setPreferredEndpoint(string $endpoint): void
• initCache(?CacheInterface $cache = null, int $ttl = 86400): void
• setClient(Client $client): void
• clearCache(): void
• clearClient(): void

Endpoint Constants

• Exchange::ENDPOINT_JSDELIVR - Use JSDelivr CDN (default)
• Exchange::ENDPOINT_CLOUDFLARE - Use Cloudflare Pages

Error Handling

The SDK handles various error scenarios gracefully:

// All methods return null on failure
$rates = Exchange::getLatestRates('invalid_currency');
if ($rates === null) {
    // Handle error
}

// Invalid endpoint configuration throws Exception
try {
    Exchange::setPreferredEndpoint('invalid_endpoint');
} catch (Exception $e) {
    // Handle error
}

Fallback Mechanism

The SDK implements a robust fallback mechanism:

1. Try preferred endpoint
2. If preferred endpoint fails, try fallback endpoint
3. Results are cached for subsequent requests
4. Cache duration is configurable

Testing

Run the test suite with PHPUnit:

./vendor/bin/phpunit

Requirements

• PHP 7.4 or higher
• Guzzle HTTP Client 7.0 or higher
• PSR-16 Simple Cache implementation

License

MIT License. See LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Credits

This package is a wrapper for the Currency Exchange API by Fawaz Ahmed.