PHP Script for macOS crypto currencies widget

crypto_coins.php

<?php
/*
 * Author: Nick Böcker
 * Created: 09.07.2017
 * Homepage: https://nick-hat-boecker.de
 */
class CryptoCoins
{
    private $curl;
    private $apiBaseUrl = 'https://min-api.cryptocompare.com/data/price';

    // #### EDIT HERE ####

    // Currencies you want to check
    private $currencies = array('STEEM', 'BTC', 'ETH', 'LTC');
    // Currencies to convert to
    private $targetCurrencies = array('USD', 'EUR');

    // #### STOP EDITING ####

    public function run()
    {
        $this->curl = curl_init();
        $this->renderPrices();
        curl_close($this->curl);
    }

    private function renderPrices()
    {
        echo "----\n";
        foreach ($this->currencies as $currency) {
            $apiUrl = $this->apiBaseUrl.'?fsym='.$currency.'&tsyms='.implode(',', $this->targetCurrencies);
            $price = $this->getPrices($apiUrl);

            echo $currency.': '.$this->getPriceString($price)."\n----\n";
        }
    }

    /**
     * @param string $apiUrl
     *
     * @return array
     */
    private function getPrices($apiUrl)
    {
        curl_setopt($this->curl, CURLOPT_URL, $apiUrl);
        curl_setopt($this->curl, CURLOPT_RETURNTRANSFER, true);

        return json_decode(curl_exec($this->curl), true);
    }

    /**
     * @param array $prices
     *
     * @return string
     */
    private function getPriceString($prices)
    {
        $strings = array();
        foreach ($prices as $currency => $price) {
            $strings[] = $currency.': '.$price;
        }

        return implode('; ', $strings);
    }
}

$cryptoCoins = new CryptoCoins();
$cryptoCoins->run();