https://github.com/Prashles/PHP-Currency-Convert-Class

Just made this class. Supports caching. I'd really appreciate any comments on how to make it better etc, just looking to improve!

Thanks :)

I've just made this class, which supports caching. I'd really appreciate any comments on how to make it better etc.

Code

<?php
/*
*
* PHP Validation Class
* 
* The currency rates are fetched and cached for the whole day
*
* http://prash.me
* http://github.com/prashles
*
* Uses http://rate-exchange.appspot.com/currency currency API
* Returns JSON - based on Google's API
*
* @author Prash Somaiya
*
*/
Class Convert {
 
 /*
 * Constructor sets to TRUE if $cacheFolder is writable
 *
 * FALSE by default
 */
 
 private $cachable = FALSE;
 
 /*
 * The folder where the cache files are stored
 * 
 * Set in the constructor. //convert by default
 */
 
 private $cacheFolder;
 
 /*
 * Length of cache in seconds
 *
 * Default is 1 day
 */
 
 private $cacheTimeout;
 
 /*
 * Check if folder is writable for caching
 *
 * Set $cache to FALSE on call to disable caching
 * $folder is where the cache files will be stored
 *
 * Set $folder to 'dcf' for the default folder
 *
 * Set $cacheTimeout for length of caching in seconds
 */
 
 public function __construct($cache = TRUE, $folder = 'dcf', $cacheTimeout = 86400)
 {
 $this->cacheFolder = ($folder == 'dcf') ? dirname(__FILE__).'/convert/' : $folder;
 
 if (is_writable($this->cacheFolder) && $cache == TRUE) { 
 $this->cachable = TRUE;
 $this->cacheTimeout = $cacheTimeout; 
 }
 }
 
 /*
 * Main function for converting
 *
 * Set $round to FALSE to return full amount
 */
 
 public function convert($amount = 1, $from = 'GBP', $to = 'USD', $round = TRUE)
 {
 
 # Check if cache file exists and pull rate
 $rate = $this->get_cache($from.$to);
 
 if ($rate !== FALSE) { 
 $return = $rate * $amount; 
 }
 
 else {
 
 if (!$this->validate_currency($to, $from)) {
 throw new Exception('Invalid currency code - must be exactly 3 letters'); 
 }
 
 $response = $this->fetch($amount, $from, $to);
 
 if (isset($response['err'])) {
 throw new Exception('Invalid input');
 }
 
 $return = $response['v'];
 
 $this->new_cache($from.$to, $response['rate']);
 
 }
 
 return ($round) ? abs(round($return, 2)) : abs($return);
 
 }
 
 /*
 * Fetches data from external API
 */
 
 protected function fetch($amount, $from, $to)
 {
 $amount = (float) $amount;
 
 $ch = curl_init();
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($ch, CURLOPT_URL, "http://rate-exchange.appspot.com/currency?q={$amount}&from={$from}&to={$to}");
 
 $response = json_decode(curl_exec($ch), true);
 
 # Caches the rate for future
 $this->new_cache($from.$to, $response['rate']);
 
 return $response; 
 
 }
 
 /*
 * Checks if file is cached then returns rate
 */
 
 protected function get_cache($file) {
 
 if ($this->cachable && file_exists($this->cacheFolder.strtoupper($file).'.convertcache')) { 
 $file = file($this->cacheFolder.$file.'.convertcache');
 
 if ($file[0] < (time() - $this->cacheTimeout)) { 
 return FALSE; 
 }
 
 return $file[1]; 
 }
 
 return FALSE;
 
 }
 
 /*
 * Calculates amount needed in currency to achieve finish currency
 *
 * Set $round to FALSE to get full value
 */
 
 public function amount_to($finalAmount, $from, $to, $round = TRUE)
 {
 $finalAmount = (float) $finalAmount;
 
 if ($finalAmount == 0) { 
 return 0;
 }
 
 if (!$this->validate_currency($from, $to)) { 
 throw new Exception('Invalid currency code - must be exactly 3 letters'); 
 }
 
 # Gets the rate
 $rate = $this->get_rate($from, $to);
 
 # Work it out
 $out = $finalAmount / $rate;
 
 return ($round) ? abs(round($out, 2)) : abs($out);
 }
 
 /*
 * Returns rate of two currencies
 */
 
 public function get_rate($from = 'GBP', $to = 'USD')
 {
 
 # Check cache
 
 $rate = $this->get_cache($from.$to);
 
 if (!$rate) { 
 $rate = $this->fetch(1, $from, $to);
 $rate = $rate['rate']; 
 }
 
 return $rate;
 
 }
 
 /*
 * Deletes all .convertcache files in cache folder
 */
 
 public function clear_cache()
 {
 $files = glob($this->cacheFolder.'*.convertcache');
 if (!empty($files)) {
 array_map('unlink', $files); 
 }
 }
 
 /*
 * Validates the currency identifier
 */
 
 protected function validate_currency()
 {
 foreach (func_get_args() as $val) { 
 if (strlen($val) !== 3 || !ctype_alpha($val)) { 
 return FALSE; 
 }
 }
 
 return TRUE; 
 
 }
 
 /*
 * Checks if file is cacheable then creates new file
 */
 
 protected function new_cache($file, $rate)
 {
 
 if ($this->cachable) { 
 $file = strtoupper($file).'.convertcache';
 
 $data = time().PHP_EOL.$rate;
 file_put_contents($this->cacheFolder.$file, $data); 
 }
 
 }
 
}

<?php
/*
*
* PHP Validation Class
* 
* The currency rates are fetched and cached for the whole day
*
* http://prash.me
* http://github.com/prashles
*
* Uses http://rate-exchange.appspot.com/currency currency API
* Returns JSON - based on Google's API
*
* @author Prash Somaiya
*
*/
Class Convert {
 
 /*
 * Constructor sets to TRUE if $cacheFolder is writable
 *
 * FALSE by default
 */
 
 private $cachable = FALSE;
 
 /*
 * The folder where the cache files are stored
 * 
 * Set in the constructor. //convert by default
 */
 
 private $cacheFolder;
 
 /*
 * Length of cache in seconds
 *
 * Default is 1 day
 */
 
 private $cacheTimeout;
 
 /*
 * Check if folder is writable for caching
 *
 * Set $cache to FALSE on call to disable caching
 * $folder is where the cache files will be stored
 *
 * Set $folder to 'dcf' for the default folder
 *
 * Set $cacheTimeout for length of caching in seconds
 */
 
 public function __construct($cache = TRUE, $folder = 'dcf', $cacheTimeout = 86400)
 {
 $this->cacheFolder = ($folder == 'dcf') ? dirname(__FILE__).'/convert/' : $folder;
 
 if (is_writable($this->cacheFolder) && $cache == TRUE) { 
 $this->cachable = TRUE;
 $this->cacheTimeout = $cacheTimeout; 
 }
 }
 
 /*
 * Main function for converting
 *
 * Set $round to FALSE to return full amount
 */
 
 public function convert($amount = 1, $from = 'GBP', $to = 'USD', $round = TRUE)
 {
 
 # Check if cache file exists and pull rate
 $rate = $this->get_cache($from.$to);
 
 if ($rate !== FALSE) { 
 $return = $rate * $amount; 
 }
 
 else {
 
 if (!$this->validate_currency($to, $from)) {
 throw new Exception('Invalid currency code - must be exactly 3 letters'); 
 }
 
 $response = $this->fetch($amount, $from, $to);
 
 if (isset($response['err'])) {
 throw new Exception('Invalid input');
 }
 
 $return = $response['v'];
 
 $this->new_cache($from.$to, $response['rate']);
 
 }
 
 return ($round) ? abs(round($return, 2)) : abs($return);
 
 }
 
 /*
 * Fetches data from external API
 */
 
 protected function fetch($amount, $from, $to)
 {
 $url = "http://rate-exchange.appspot.com/currency?q={$amount}&from={$from}&to={$to}";
 $amount = (float) $amount;
 
 if (in_array('curl', get_loaded_extensions())) {
 
 $ch = curl_init();
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($ch, CURLOPT_URL, "http://rate-exchange.appspot.com/currency?q={$amount}&from={$from}&to={$to}");
 
 $response = json_decode(curl_exec($ch), true);
 }
 else {
 $response = json_decode(file_get_contents($url), true);
 }
 
 # Caches the rate for future
 $this->new_cache($from.$to, $response['rate']);
 
 return $response; 
 
 }
 
 /*
 * Checks if file is cached then returns rate
 */
 
 protected function get_cache($file) {
 
 if ($this->cachable && file_exists($this->cacheFolder.strtoupper($file).'.convertcache')) { 
 $file = file($this->cacheFolder.$file.'.convertcache');
 
 if ($file[0] < (time() - $this->cacheTimeout)) { 
 return FALSE; 
 }
 
 return $file[1]; 
 }
 
 return FALSE;
 
 }
 
 /*
 * Calculates amount needed in currency to achieve finish currency
 *
 * Set $round to FALSE to get full value
 */
 
 public function amount_to($finalAmount, $from, $to, $round = TRUE)
 {
 $finalAmount = (float) $finalAmount;
 
 if ($finalAmount == 0) { 
 return 0;
 }
 
 if (!$this->validate_currency($from, $to)) { 
 throw new Exception('Invalid currency code - must be exactly 3 letters'); 
 }
 
 # Gets the rate
 $rate = $this->get_rate($from, $to);
 
 # Work it out
 $out = $finalAmount / $rate;
 
 return ($round) ? round($out, 2) : $out;
 }
 
 /*
 * Returns rate of two currencies
 */
 
 public function get_rate($from = 'GBP', $to = 'USD')
 {
 
 # Check cache
 
 $rate = $this->get_cache($from.$to);
 
 if (!$rate) { 
 $rate = $this->fetch(1, $from, $to);
 $rate = $rate['rate']; 
 }
 
 return $rate;
 
 }
 
 /*
 * Deletes all .convertcache files in cache folder
 */
 
 public function clear_cache()
 {
 $files = glob($this->cacheFolder.'*.convertcache');
 if (!empty($files)) {
 array_map('unlink', $files); 
 }
 }
 
 /*
 * Validates the currency identifier
 */
 
 protected function validate_currency()
 {
 foreach (func_get_args() as $val) { 
 if (strlen($val) !== 3 || !ctype_alpha($val)) { 
 return FALSE; 
 }
 }
 
 return TRUE; 
 
 }
 
 /*
 * Checks if file is cacheable then creates new file
 */
 
 protected function new_cache($file, $rate)
 {
 
 if ($this->cachable) { 
 $file = strtoupper($file).'.convertcache';
 
 $data = time().PHP_EOL.$rate;
 file_put_contents($this->cacheFolder.$file, $data); 
 }
 
 }
 
}