README

National Bank of Georgia (NBG) currency service API wrapper in PHP

Installation

Install this package via Composer.

composer require stichoza/nbg-currency

Note PHP 8.1 or later is required. Use following versions of this package for older PHP versions:

Quick Examples

NbgCurrency::rate('usd'); // 2.7177
NbgCurrency::rate('usd', '2022-12-02'); // 2.7112

NbgCurrency::get('usd')->rate; // 2.7177
NbgCurrency::get('usd', '2022-12-02')->rate; // 2.7112
NbgCurrency::get('usd', '2022-12-02', 'en')->name; // US Dollar

NbgCurrency::date(Carbon::yesterday())->get('usd')->diff; // 0.0012
NbgCurrency::date('2022-12-02', 'en')->get('usd')->increased(); // true

Continue reading for more details about additional functionality.

Basic Usage

The class is namespaced as Stichoza\NbgCurrency\NbgCurrency:

use Stichoza\NbgCurrency\NbgCurrency;

This package has three main static methods from which you can access currency rates.

Get Currency Rate

The NbgCurrency::rate() method returns a currency rate in float.

NbgCurrency::rate(string $code, DateTimeInterface|string|null $date = null): float

Important The rate is always for a single unit. The original NBG JSON API returns rate for different amounts per currency. For example Japanese Yen (JPY) rate will be 1.9865 and quantity will be set to 100 (100 JPY is 1.9865 GEL). It is quite confusing during calculations so this package always returns price per single unit. So in this case JPY will be 0.019865 (1 JPY is 0.019865 GEL).

Examples:

NbgCurrency::rate('usd'); // Returns current rate of USD. Example: 2.7177
NbgCurrency::rate('usd', '2022-12-02'); // USD rate on 2022-12-02
NbgCurrency::rate('eur', 'yesterday'); // EUR rate from yesterday. Strings are parsed via Carbon::parse()
NbgCurrency::rate('eur', Carbon::yesterday()); // EUR rate from yesterday
NbgCurrency::rate('gbp', Carbon::today()->subDays(5)); // GBP rate 5 days ago
NbgCurrency::rate('gbp', new DateTime()); // GBP rate today

if (NbgCurrency::rate('usd') > 3) {
    echo 'Oh no!';
}

When passing dates as Carbon or DateTime objects, it's recommended to have its timezone set to Asia/Tbilisi to avoid unexpected behavior. For convenience, timezone string is available as NbgCurrency::TIMEZONE class constant.

Get Currency Object

The NbgCurrency::get() method returns a Currency object containing data of a currency for specified date.

This method accepts same parameters as ::rate() method and one additional parameter for language (Used for currency name).

NbgCurrency::get(string $code, DateTimeInterface|string|null $date = null, string $language = 'ka'): Currency

Examples:

$usd = NbgCurrency::get('usd'); // Currency object (Stichoza\NbgCurrency\Data\Currency)

$usd->code; // USD
$usd->rate; // 2.7112
$usd->name; // აშშ დოლარი
$usd->diff; // -0.0065
$usd->date; // Carbon object of date: 2022-12-01 17:45:12
$usd->validFrom; // Carbon object since when the rate is valid: 2022-12-02 00:00:00
$usd->change; // Currency rate change. -1 if decreased, 0 if unchanged and 1 if increased.

// Using methods available on Carbon objects
$usd->date->format('j F Y'); // 1 December 2022
$usd->date->diffForHumans(); // 3 days ago
$usd->validFrom->isPast(); // true

// Additional methods
$usd->increased(); // Returns true if rate has increased, false otherwise.
$usd->decreased(); // Returns true if rate has decreased, false otherwise.
$usd->unchanged(); // Returns true if rate hasn't changed, false otherwise.

// The changeString() method returns first parameter if rate was increased, second string if there was
// no change and third string if the rate went up. Useful for CSS classes, font icons, etc.
$class = $usd->changeString('text-red', 'text-gray', 'text-green');
$icon  = $usd->changeString('fa-arrow-down', 'fa-circle', 'fa-arrow-down');

Note All properties of Currency class are declared as readonly. Updating them will result in Fatal Error.

Advanced Usage

Get All Currencies

The NbgCurrency::date() method will return a Currencies object. This is a collection-like object that contains a list of all Currency objects available for specified date.

NbgCurrency::date(DateTimeInterface|string|null $date = null, string $language = 'ka'): Currencies

Examples:

$currencies = NbgCurrency::date('3 days ago');
$currencies = NbgCurrency::date(Carbon::now()->startOfMonth(), 'en');

Currencies class has date attribute and several methods that you can use.

$currencies->date; // Carbon object of date

$currencies->get('usd'); // Returns Currency object for USD
$currencies->has('eur'); // True if EUR currency is contained in $currencies collection
$currencies->count(); // Count of Currency objects in collection

$currencies->get('usd')->rate; // Currency rate of USD
$currencies->get('eur')->date->diffForHumans(); // 10 days ago

Note that ->get() method of Currencies object has only one parameter string $code, while the static method with the same name (NbgCurrency::get()) has two additional parameters described in basic usage examples above.

The Currencies object also implements Countable and IteratorAggregate interfaces, so you can use the object in foreach loops and count() function.

Examples:

$currencies = NbgCurrency::date('2022-12-02', 'en'); // Currencies object (Stichoza\NbgCurrency\Data\Currencies) 

echo 'Total ' . count($currencies) . ' currencies for ' . $currencies->date->toFormattedDateString();
// Total 43 currencies for Dec 2, 2022

foreach ($currencies as $code => $currency) {
    echo $currency->code . ' costs ' . $currency->rate;
}
// AED costs 7.3662
// AMD costs 6.8453
// ...

Error Handling

There are 5 exceptions in Stichoza\NbgCurrency\Exceptions namespace that could be thrown from methods:

• CurrencyNotFoundException - If currency is not available.
• DateNotFoundException - If specified date is not available.
• LanguageNotFoundException - If specified language is not available.
• InvalidDateException - If the specified date is in invalid format or cannot be parsed.
• RequestFailedException - If there was an error during API request.

All exceptions above extend Exception class, so you can handle all exceptions by catching Exception or Throwable.

try {
    $usdRate = NbgCurrency::date('10 days ago', 'en')->get('usd')->rate;
} catch (Exception) {
    // Whoops...
}

Additional Info

Number of HTTP Requests

When you access any currency, all currencies for that day in selected language will be fetched (API returns all currencies in a single request) and stored in NbgCurrency class attribute. When you request any other currency, no additional HTTP requests will be made for same date and language.

// Next 3 method calls will result in 1 HTTP request in total.
NbgCurrency::rate('usd');
NbgCurrency::rate('eur');
NbgCurrency::rate('gbp');

// Next 3 method calls will result in 3 HTTP requests in total.
NbgGurrency::rate('usd', '2022-10-10');
NbgGurrency::rate('eur', '2022-11-11', 'en');
NbgGurrency::rate('gbp', '2022-11-11');

// Next 3 method calls will result in 2 HTTP request in total.
NbgGurrency::rate('usd', '2022-11-11');
NbgGurrency::rate('eur', '2022-11-11');
NbgGurrency::rate('gbp', '2022-11-11', 'en');

Memory Usage & Caching

By default, all retrieved currencies are stored in a static property of NbgCurrency class. If you're planning to get currencies for many different dates, it might use excessive memory. In this case it's recommended to turn off the caching feature.

NbgCurrency::disableCaching(); // Disable caching, also removes data stored in the property.
NbgCurrency::enableCaching(); // Enables caching in class property.

On the other hand, disabling caching may increase number of HTTP requests being sent. Example:

$codes = ['USD', 'EUR', 'GBP', 'UAH', 'JPY'];

foreach ($codes as $code) {
    echo NbgCurrency::rate($code);
}

The above code would make a single HTTP request to the API when caching is enabled. But if you disable caching, it will send 5 separate HTTP requests. To load multiple currencies of same date using a single HTTP request with caching disabled, you can use ::date() method to get Currencies object and then access all contained objects after.

$codes = ['USD', 'EUR', 'GBP', 'UAH', 'JPY'];

$currencies = NbgCurrency::date();

foreach ($codes as $code) {
    echo $currencies->get($code)->rate;
}

In this case there will be a single HTTP request made even with caching disabled.

Keywords

ლარის კურსი, ეროვნული ბანკის გაცვლითი კურსი, ვალუტა, ლარის ვალუტის კურსი, laris kursi, laris valuta, lari currency, national bank of georgia, nbg