eurofxref.php

<?php
/**
 * Plugin Name: Euro FxRef Currency Converter
 * Plugin URI: https://wordpress.org/plugins/euro-fxref-currency-converter/
 * Description: Adds the [currency] and [currency_legal] shortcodes to convert currencies based on the ECB reference exchange rates. Please visit <a href="https://wordpress.org/plugins/euro-fxref-currency-converter/" target="_blank">the plugin page on WordPress.org</a> for help and options.
 * Text Domain: euro-fxref-currency-converter
 * Version: 2.0.2
 * Author: Joost de Keijzer
 * Author URI: https://dkzr.nl/
 * Requires at least: 3.3
 * Requires PHP: 7.0
 * License: GPLv2 or later
 * License URI: http://www.gnu.org/licenses/gpl-2.0.html
 *
 * Development code at https://github.com/joostdekeijzer/wp_eurofxref
 *
 * This plugin is based on the Xclamation Currency Converter Shortcode plugin.
 * See http://www.xclamationdesign.co.uk/free-currency-converter-shortcode-plugin-for-wordpress/
 * for more information.
 */

if ( !function_exists( 'add_action' ) ) {
	echo "Hi there!  I'm just a plugin, not much I can do when called directly.";
	exit;
}

class EuroFxRef {
	static protected $euroFxRef;
	const TRANSIENT_LABEL = 'EuroFxRefRates';

	public $space = '&nbsp;';

	public function __construct() {
		// for testing
		//delete_transient( self::TRANSIENT_LABEL );

		add_shortcode( 'currency', array( $this, 'currency_shortcode' ) );
		add_shortcode( 'currency_legal', array( $this, 'currency_legal_shortcode' ) );

		add_action( 'admin_head', array( $this, 'insert_help_tab' )  );
	}

	/**
	 * Available for static calling.
	 */
	public static function legal_string( $prepend = '* ' ) {
		return self::currency_legal_shortcode( array( 'prepend' => $prepend ) );
	}

	public static function convert( $amount = 0, $from = 'EUR', $to = 'USD' ) {
		$from = strtoupper( $from );
		$to   = strtoupper( $to );

		if( ( 'EUR' != $from && null === self::getEuroFxRef( $from ) ) || ( 'EUR' != $to && null === self::getEuroFxRef( $to ) ) ) {
			return false;
		}

		if( 'EUR' != $from && 'EUR' != $to ) {
			// normalize on Euro
			$amount = self::convert( $amount, $from, 'EUR' );
			$from = 'EUR';
		}

		if( 'EUR' == $from ) {
			// from Euro to ...
			return $amount * self::getEuroFxRef( $to );
		} else {
			// from ... to Euro
			return $amount / self::getEuroFxRef( $from );
		}
	}

	/**
	 * Available for static calling.
	 */
	public function currency_converter( $atts ) {
		_deprecated_function( __METHOD__, 'euro-fxref-currency-converter-2.0.1', 'EuroFxRef::currency_shortcode' );
		return $this->currency_shortcode( $atts );
	}

	public function currency_shortcode( $atts ) {
		extract( shortcode_atts( array(
			'from'              => 'EUR',
			'to'                => 'USD',
			'amount'            => 1,
			'iso'               => false,
			'show_from'         => true,
			'between'           => '&nbsp;/&nbsp;',
			'append'            => '&nbsp;*',
			'round'             => true,
			'round_append'      => '=',
			'no_from_show_rate' => true,
			'to_style'          => 'cursor:help;border-bottom:1px dotted gray;',
			//'flag' => '',
		), $atts, 'currency' ) );

		// fix booleans
		foreach( array( 'iso', 'show_from', 'no_from_show_rate', 'round' ) as $var ) {
			$$var = $this->_bool_from_string( $$var );
		}

		$currency = $this->get_currency_symbols();
		$number_format = $this->get_number_formats();

		if( !isset( $currency[ $from ] ) || !isset( $currency[ $to ] ) ) {
			$currency[ $from ] = $currency[ $to ] = '';
			$number_format[ $from ] = $number_format[ $to ] = array( 'dp' => ',', 'ts' => '.' );
			$iso = true;
		}

		$cAmount = self::convert( floatval( $amount ), $from, $to );
		if( false !== $cAmount ) {
			$cAmount = number_format( $cAmount, ( $round ? 0 : 2 ), $number_format[$to]['dp'], $number_format[$to]['ts'] );
			if( $round && '' != $round_append ) $cAmount .= $number_format[$to]['dp'] . $round_append;
		}

		$amount = number_format( $amount, ( $round ? 0 : 2 ), $number_format[$from]['dp'], $number_format[$from]['ts'] );
		if( $round && '' != $round_append ) $amount .= $number_format[$from]['dp'] . $round_append;

		$s = $this->space;
		if( $show_from || false === $cAmount ) {
			if( $iso ) {
				$output = $amount . $s . $from;
				if( false !== $cAmount )
					$output .= $between . $cAmount . $s . $to;
			} else {
				$output = $currency[$from] . $s . $amount;
				if( false !== $cAmount )
					$output .= $between . $currency[$to] . $s . $cAmount;
			}
		} else {
			if( $iso ) {
				$output = $cAmount . $s . $to;
			} else {
				$output = $currency[$to] . $s . $cAmount;
			}

			if ( $no_from_show_rate ) {
				$cOne = number_format( self::convert( 1, strtoupper( $from ), strtoupper( $to ) ), 4, $number_format[$to]['dp'], $number_format[$to]['ts'] );
				$output = sprintf( '<span class="eurofxref-conversion-rate" style="%s" title="%s">%s</span>', esc_attr( $to_style ), esc_attr( "1 {$from} = {$cOne} {$to}" ), $output );
			}
		}

		if ( $append ) {
			$output .= sprintf( '<span class="eurofxref-append-string">%s</span>', $append );
		}

		return $output;
	}

	public static function currency_legal_shortcode( $atts ) {
		$atts = shortcode_atts( array(
			'prepend' => '* ',
		), $atts, 'currency_legal' );

		$output = '';

		if ( $atts['prepend'] ) {
			$output = sprintf( '<span class="eurofxref-prepend-string">%s</span>', $atts['prepend'] );
		}


		return $output . sprintf( __( 'For informational purposes only. Exchange rates may vary. Based on <a href="%s" target="_blank">ECB reference rates</a>.', 'euro-fxref-currency-converter' ), 'https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/' );
	}

	public function insert_help_tab() {
		global $post_type;
		$screen = get_current_screen();
		if( 'post' != $screen->base || !post_type_supports($post_type, 'editor') ) return;
	
		$id = __CLASS__ . '_help_id';
		$title = __( "Using the [currency] shortcodes", __CLASS__ );
		$help = <<<EOH
<p><strong>currency</strong> shortcode examples:<br/>
	<code>[currency from="EUR" to="GBP" amount="10"]</code><br/>
	<code>[currency from="JPY" to="CHF" amount="750"]</code></p>
<p>Full example with default values:<br/>
	<code>[currency from="EUR" to="USD" amount="1" iso=false show_from=true between="&amp;nbsp;/&amp;nbsp;" append="&amp;nbsp;*" round=true round_append="=" to_style="cursor:help;border-bottom:1px dotted gray;"]</code></p>

<p><strong>currency_legal</strong> shortcode examples:<br/>
	<code>[currency_legal]</code><br/>
	<code>[currency_legal prepend='* ']</code> (full example with default value)</p>
<p>The legal text is:<br/>
	'For informational purposes only. Exchange rates may vary. Based on <a href="https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/" target="_blank">ECB reference rates</a>.'</p>

<p><strong>Need more help?</strong><br/>
	Please visit <a href="https://wordpress.org/plugins/euro-fxref-currency-converter/" target="_blank">https://wordpress.org/plugins/euro-fxref-currency-converter/</a> for more examples and a full list of supported currencies.</p>
EOH;

		$screen->add_help_tab( array(
			'id' => $id,
			'title' => $title,
			'content' => $help,
		) );
	}

	/**
	 * First copied from xclam_currency_converter, modified with WooCommerce `WooCommerce\Functions wc-core-functions.php` and `WooCommerce\i18n currency-info.php` input.
	 *
	 * @see https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/html/index.en.html
	 *
	 * $symbols['LTL'] = 'Lt';       // Lithuanian Litas - not published since 2020-01-02
	 * $symbols['LVL'] = 'Ls';       // Latvian Lats     - not published since 2020-01-02
	 * $symbols['RUB'] = '&#8381;';  // Russian Rouble   - not published since 2022-06-01
	 * $symbols['HRK'] = 'kn';       // Croatian Kuna    - not published since 2023-01-02
	 */
	public function get_currency_symbols() {
		$symbols = apply_filters(
			'eurofxref_currency_symbols',
			array(
				'AUD' => '&#36;',			// Australian dollar
				'BGN' => '&#1083;&#1074;.',	// Bulgarian lev
				'BRL' => '&#82;&#36;',		// Brazilian real
				'CAD' => '&#36;',			// Canadian dollar
				'CHF' => '&#67;&#72;&#70;',	// Swiss franc
				'CNY' => '&yen;',			// Chinese yuan
				'CZK' => '&#75;&#269;',		// Czech koruna
				'DKK' => 'kr.',				// Danish krone
				'EUR' => '&euro;',			// Euro
				'GBP' => '&pound;',			// Pound sterling
				'HKD' => '&#36;',			// Hong Kong dollar
				'HUF' => '&#70;&#116;',		// Hungarian forint
				'IDR' => 'Rp',				// Indonesian rupiah
				'ILS' => '&#8362;',			// Israeli new shekel
				'INR' => '&#8377;',			// Indian rupee
				'ISK' => 'kr.',				// Icelandic króna
				'JPY' => '&yen;',			// Japanese yen
				'KRW' => '&#8361;',			// South Korean won
				'MXN' => '&#36;',			// Mexican peso
				'MYR' => '&#82;&#77;',		// Malaysian ringgit
				'NOK' => '&#107;&#114;',	// Norwegian krone
				'NZD' => '&#36;',			// New Zealand dollar
				'PHP' => '&#8369;',			// Philippine peso
				'PLN' => '&#122;&#322;',	// Polish złoty
				'RON' => 'lei',				// Romanian leu
				'SEK' => '&#107;&#114;',	// Swedish krona
				'SGD' => '&#36;',			// Singapore dollar
				'THB' => '&#3647;',			// Thai baht
				'TRY' => '&#8378;',			// Turkish lira
				'USD' => '&#36;',			// United States (US) dollar
				'ZAR' => '&#82;',			// South African rand
			)
		);

		return apply_filters( 'woocommerce_currency_symbols', $symbols );
	}

	/**
	 * Copied from xclam_currency_converter
	 */
	public function get_number_formats() {
		$formats = apply_filters(
			'eurofxref_number_formats',
			array(
				'AUD' => array( 'dp' => '.', 'ts' => ',' ),
				'BGN' => array( 'dp' => ',', 'ts' => '&nbsp;', 'after' => true ),
				'BRL' => array( 'dp' => ',', 'ts' => '.' ),
				'CAD' => array( 'dp' => '.', 'ts' => ',' ),
				'CHF' => array( 'dp' => '.', 'ts' => '&rsquo;', 'after' => true ),
				'CNY' => array( 'dp' => '.', 'ts' => ',' ),
				'CZK' => array( 'dp' => '.', 'ts' => '&nbsp;', 'after' => true ),
				'DKK' => array( 'dp' => ',', 'ts' => '.', 'after' => true ),
				'EUR' => array( 'dp' => ',', 'ts' => '.' , 'after' => false ),
				'GBP' => array( 'dp' => '.', 'ts' => ',' ),
				'HKD' => array( 'dp' => '.', 'ts' => ',' ),
				'HUF' => array( 'dp' => ',', 'ts' => '&nbsp;', 'after' => true, 'round' => true ),
				'IDR' => array( 'dp' => ',', 'ts' => '.', 'round' => true ),
				'ILS' => array( 'dp' => '.', 'ts' => ',', 'after' => true ),
				'INR' => array( 'dp' => '.', 'ts' => ',' ),
				'ISK' => array( 'dp' => '.', 'ts' => ',' ),
				'JPY' => array( 'dp' => '.', 'ts' => ',', 'round' => true ),
				'KRW' => array( 'dp' => '.', 'ts' => ',', 'round' => true ),
				'MXN' => array( 'dp' => '.', 'ts' => ',' ),
				'MYR' => array( 'dp' => '.', 'ts' => ',' ),
				'NOK' => array( 'dp' => ',', 'ts' => '&nbsp;' ),
				'NZD' => array( 'dp' => '.', 'ts' => ',' ),
				'PHP' => array( 'dp' => '.', 'ts' => ',' ),
				'PLN' => array( 'dp' => ',', 'ts' => '&nbsp;', 'after' => true ),
				'RON' => array( 'dp' => ',', 'ts' => '.', 'after' => true ),
				'SEK' => array( 'dp' => ',', 'ts' => '&nbsp;', 'after' => true ),
				'SGD' => array( 'dp' => '.', 'ts' => ',' ),
				'THB' => array( 'dp' => '.', 'ts' => ',' ),
				'TRY' => array( 'dp' => ',', 'ts' => '.', 'after' => true ),
				'USD' => array( 'dp' => '.', 'ts' => ',' ),
				'ZAR' => array( 'dp' => ',', 'ts' => '&nbsp;' ),
			)
		);

		return $formats;
	}

	protected static function getEuroFxRef( $currency = null ) {
		global $wp_version;

		if( !isset(self::$euroFxRef) || false == self::$euroFxRef || 0 == count(self::$euroFxRef) ) {
			self::$euroFxRef = get_transient( self::TRANSIENT_LABEL );

			if( false == self::$euroFxRef || 0 == count(self::$euroFxRef) ) {
				//This is a PHP(5)script example on how eurofxref-daily.xml can be parsed
				//the file is updated daily at 16:00 CET
		
				//Read eurofxref-daily.xml file in memory
				//For the next command you will need the config option allow_url_fopen=On (default)
				$response = wp_remote_get('https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml', array('user-agent' => 'Euro FxRef Currency Converter plugin on WordPress/' . $wp_version . '; ' . home_url()));

				self::$euroFxRef = array();
				if( !is_wp_error( $response ) ) {
					libxml_use_internal_errors(true);
					$fxRefXml = simplexml_load_string( $response['body'] );
					if ( libxml_get_errors() ) {
						return null;
					}

					$fxRefDateString = (string) $fxRefXml->Cube->Cube['time'];

					foreach($fxRefXml->Cube->Cube->Cube as $rate) {
						self::$euroFxRef[ (string) $rate['currency'] ] = (float) $rate['rate'];
					}

					/**
					 * Calculate transient expiration to try update around 17h00 daily
					 * with a minimum of 15 minutes and a maximum of 6 hours.
					 * ECB publishes around 16h00 daily so around 17h00 the new rates should be published.
					 * 
					 * All calculated in Seconds since the Unix Epoch to support PHP 5.2
					 */
					$pubEpoch = date_format( new DateTime( $fxRefDateString, new DateTimeZone('CET') ), 'U' );
					$pubEpoch += 60 * 60 * 17; // add 17h to be around 1 (one) hour past actual publication date
					$pubEpoch += 60 * 60 * 24; // add 24h for NEXT publication date

					$transient_expiration = min( 60 * 60 * 6, max( 60 * 15, $pubEpoch - date_format( new DateTime( 'now', new DateTimeZone('CET') ), 'U' ) ) );

					set_transient( self::TRANSIENT_LABEL, self::$euroFxRef, $transient_expiration );
				}
			}
		}
		if( isset($currency) ) {
			if( isset( self::$euroFxRef[$currency] ) ) {
				return self::$euroFxRef[$currency];
			} else {
				return null;
			}
		} else {
			return self::$euroFxRef;
		}
	}

	/**
	 * converts strings and integers to boolean values.
	 * 0, "0", false, "FALSE", "no", 'n' etc. becomes (bool) false
	 * all other becomes (bool) true.
	 * 
	 * The function itself defaults to (bool) false
	 * 
	 * Also see http://php.net/manual/en/function.is-bool.php#93165
	 */
	private function _bool_from_string( $val = false ) {
		if( is_bool( $val ) ) return $val;

		$val = strtolower( trim( $val ) );

		if(
			'false' == $val ||
			'null' == $val ||
			'off' == $val ||
			'no' == $val ||
			'n' == $val ||
			'0' == $val
		) {
			return false;
		} else {
			return true;
		}
	}
}
$EuroFxRef = new EuroFxRef();