Proxies and Dummy Services

Proxies and Dummy Services are defined in the core library, peso/core.

ChainService

\Peso\Core\Services\ChainService($service1, $service2, ...)

Chain service allows you to request data from several sources:

<?php

use Peso\Core\Services\ChainService;
use Peso\Peso\CurrencyConverter;
use Peso\Services\CzechNationalBankService;
use Peso\Services\EuropeanCentralBankService;

$converter = new CurrencyConverter(new ChainService(
    new EuropeanCentralBankService(),
    new CzechNationalBankService(),
));

// ECB doesn't know that
echo $converter->convertOnDate('1.20', 'USD', 'CZK', 2, '2025-06-13'); // 25.88

ReversibleService

\Peso\Core\Services\ReversibleService

Warning

Values returned by a Reversible Service are calculated and therefore informational only. Never use them for precise conversions.

In case a service defines only a single base or quote currency, Reversible Service can make it bi-directional by calculating a reverse value:

<?php

use Peso\Core\Services\ReversibleService;
use Peso\Peso\CurrencyConverter;
use Peso\Services\EuropeanCentralBankService;

$converter = new CurrencyConverter(
    new ReversibleService(new EuropeanCentralBankService())
);

echo $converter->convertOnDate('123.45', 'USD', 'EUR', 2, '2025-06-13'); // 107.24

IndirectExchangeService

\Peso\Core\Services\IndirectExchangeService

Warning

Values returned by an Indirect Exchange Service are calculated and therefore informational only. Never use them for precise conversions.

In case a service defines only conversion rates back and forth for a single currency, Indirect Exchange Service can make it every-to-every by using the selected currency as an intermediary:

<?php

use Peso\Core\Services\IndirectExchangeService;
use Peso\Core\Services\ReversibleService;
use Peso\Peso\CurrencyConverter;
use Peso\Services\EuropeanCentralBankService;

$converter = new CurrencyConverter(
    new IndirectExchangeService(
        new ReversibleService( // To and from EUR
            new EuropeanCentralBankService(), // Only EUR base
        ),
        'EUR',
    ),
);

// USD -> EUR -> PLN
echo $converter->convertOnDate('123.45', 'USD', 'PLN', 2, '2025-06-13'); // 458.38

ArrayService

\Peso\Core\Services\ArrayService($currentRates = [], $historicalRates = [])

Array Service holds static exchange rates:

<?php

use Peso\Core\Services\ArrayService;
use Peso\Peso\CurrencyConverter;

$service = new ArrayService(
    currentRates: [
        // Base Currencies
        'EUR' => [
            // Quote => rate
            'USD' => '1.12',
        ],
    ],
    historicalRates: [
        // Y-m-d dates
        '2025-06-13' => [
            // Base Currencies
            'EUR' => [
                // Quote => rate
                'USD' => '1.09',
            ],
        ],
    ]
);
$converter = new CurrencyConverter($service);

echo
    $converter->convert('150.00', 'EUR', 'USD', 2), PHP_EOL, // 168.00
    $converter->convertOnDate('150.00', 'EUR', 'USD', 2, '2025-06-13'), PHP_EOL; // 163.50

NullService

\Peso\Core\Services\NullService

Null Service fails every request, may be useful for testing purposes:

<?php

use Peso\Core\Services\NullService;
use Peso\Peso\CurrencyConverter;

$converter = new CurrencyConverter(new NullService());

// Peso\Core\Exceptions\RequestNotSupportedException
$converter->convert('100', 'USD', 'EUR', 2);