convertAmountToUSD.php

<?php
class EventbookingHelper
{
	/**
	 * Convert payment amount to USD currency in case the currency is not supported by the payment gateway
	 *
	 * @param $amount
	 * @param $currency
	 *
	 * @return float
	 */
	public static function convertAmountToUSD($amount, $currency)
	{
		if (EventbookingHelper::isMethodOverridden('EventbookingHelperOverrideHelper', 'convertAmountToUSD'))
		{
			return EventbookingHelperOverrideHelper::convertAmountToUSD($amount, $currency);
		}

		$url = sprintf('https://www.google.com/search?q=1+%s+to+%s', 'USD', $currency);

		$headers = [
			'Accept'     => 'text/html',
			'User-Agent' => 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:21.0) Gecko/20100101 Firefox/21.0',
		];

		$http     = JHttpFactory::getHttp();
		$response = $http->get($url, $headers);

		if (302 == $response->code && isset($response->headers['Location']))
		{
			$response = $http->get($response->headers['Location'], $headers);
		}

		$body = $response->body;

		try
		{
			$rate = static::buildExchangeRate($body);

			if ($rate > 0)
			{
				$amount = $amount / $rate;
			}
		}
		catch (Exception $e)
		{

		}

		return round($amount, 2);
	}


	/**
	 * Builds an exchange rate from the response content.
	 *
	 * @param string $content
	 *
	 * @return float
	 *
	 * @throws \Exception
	 */
	protected static function buildExchangeRate($content)
	{
		$document = new \DOMDocument();

		if (false === @$document->loadHTML('<?xml encoding="utf-8" ?>' . $content))
		{
			throw new Exception('The page content is not loadable');
		}

		$xpath = new \DOMXPath($document);
		$nodes = $xpath->query('//span[@id="knowledge-currency__tgt-amount"]');

		if (1 !== $nodes->length)
		{
			$nodes = $xpath->query('//div[@class="vk_ans vk_bk" or @class="dDoNo vk_bk"]');
		}

		if (1 !== $nodes->length)
		{
			throw new Exception('The currency is not supported or Google changed the response format');
		}

		$nodeContent = $nodes->item(0)->textContent;

		// Beware of "3 417.36111 Colombian pesos", with a non breaking space
		$bid = strtr($nodeContent, ["\xc2\xa0" => '']);

		if (false !== strpos($bid, ' '))
		{
			$bid = strstr($bid, ' ', true);
		}
		// Does it have thousands separator?
		if (strpos($bid, ',') && strpos($bid, '.'))
		{
			$bid = str_replace(',', '', $bid);
		}

		if (!is_numeric($bid))
		{
			throw new Exception('The currency is not supported or Google changed the response format');
		}

		return $bid;
	}
}