Eu.php

<?php
namespace ArrayIterator\Currency\Daily;

class Eu
{
    const API_URI = 'http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml';

    /**
     * @var string
     */
    protected static $needTheDate;

    /**
     * @var int
     */
    protected static $currentDate;

    /**
     * @var array
     */
    protected static $rates;

    /**
     * {@inheritdoc}
     */
    public function __construct()
    {
        self::$currentDate = strtotime(gmdate('Y-m-d H:i:s \G\M\T', time()));
        self::$needTheDate = strtotime(date('Y-m-d', self::$currentDate) .' 14:15 CET'); // for cache date identifier 2:15PM
    }

    /**
     * Set Error Handler
     */
    protected static function createSetErrorHandler()
    {
        set_error_handler(function () {
            error_clear_last();
        });
    }
    /**
     * Restore Handler
     */
    protected static function restoreErrorHandler()
    {
        restore_error_handler();
    }

    /**
     * @return array
     */
    public static function getRates() : array
    {
        if (! empty(self::$rates) && is_array(self::$rates)) {
            return self::$rates;
        }
        /* // add cache logic / database worker here
        $cacheKey = Cache::createUniqueKey(__CLASS__, 'rates');
        if ((self::$needTheDate - self::$currentDate) < 3600) {
            Cache::delete($cacheKey);
        }

        $rates = Cache::get($cacheKey);
        if (is_array($rates) && !empty($rates)) {
            ksort($rates, SORT_ASC);
            return self::$rates = $rates;
        }*/

        $xml  = simplexml_load_file(self::API_URI);
        self::createSetErrorHandler();
        $data = [];
        foreach ($xml->Cube->Cube->Cube as $item) {
            if (! isset($item['currency']) || ! isset($item['rate'])) {
                self::restoreErrorHandler();
                return [];
            }

            $currency        = strtoupper((string)$item['currency']);
            $rate            = (string)$item['rate'];
            $data[$currency] = $rate;
        }

        self::restoreErrorHandler();
        $data['EUR'] = 1 / $data['USD'];
        $data['USD'] = 1.0;
        foreach ($data as $key => $v) {
            if ($key === 'USD' || $key === 'EUR') {
                continue;
            }
            $data[$key] = (float) $data['EUR'] * $v;
        }

        ksort($data, SORT_ASC);
        // Cache::set($cacheKey, $data, 3600*24);
        return self::$rates = $data;
    }

    /**
     * @param string $code
     *
     * @return string|null string numeric
     */
    public static function getRateFor(string $code)
    {
        $rates = self::getRates();
        $code = self::normalizeCode($code);
        return isset($rates[$code])
            ? $rates[$code]
            : null;
    }

    /**
     * @param string $code
     *
     * @return string
     */
    public static function normalizeCode(string $code) : string
    {
        return strtoupper(trim($code));
    }

    /**
     * @param string $from
     * @param string $to
     *
     * @return null
     */
    public static function convert(string $from, string $to)
    {
        $from = self::normalizeCode($from);
        $to = self::normalizeCode($to);
        if ($from === '' || $to === '') {
            return null;
        }

        if ($from === $to) {
            return $from;
        }
        if ($from === 'USD') {
            return self::getRateFor($to);
        }

        $rates['USD'] = 1;
        $rates = self::getRates();
        if (!isset($rates[$from]) || !isset($rates[$to])) {
            return null;
        }

        return ($rates[$to] / $rates[$from]);
    }

    /**
     * @param $value
     * @param string $from
     * @param string $to
     *
     * @return float|int|null
     */
    public static function convertRate($value, string $from, string $to)
    {
        $rate = self::convert($from, $to);
        if ($rate === null) {
            return null;
        }

        return $value*$rate;
    }

    /**
     * @param $rate
     * @param int $roundAdd
     *
     * @return string
     */
    public static function sanityNumber($rate, int $roundAdd = 1)
    {
        $roundAdd = $roundAdd < 0 ? 0 : $roundAdd;
        preg_match('/[\-\+]([0-9]+)$/', (string) $rate, $match);
        if (!empty($match[1])) {
            $rate = number_format((float) $rate, (int) $match[1]+$roundAdd, '.', '');
        } elseif (strpos((string) $rate, '.')) {
            $ex = explode('.', (string) $rate);
            $ex = array_pop($ex);
            if (strlen($ex) > 5) {
                $rate = number_format((float) $rate, 5, '.', '');
            }
        }

        return rtrim((string) $rate, '.0');
    }
}