php gets remote image class instance

Example, a php to get the remote image class. Code:

if ( ! defined('basepath')) exit('no direct script access allowed');
/*
 * Remote access to image class
 *
 * Requires curl extension to be turned on
 * Simulate the PHP upload principle, create a cache directory, and store remotely obtained files in the cache directory.
*/
class url_pic{
 protected $cache; //Cache path

 public function __construct($cache='')
 {
 if(!emptyempty($cache))
 {
 $this->cache = $cache;
 }
 else
 {
 $this->cache = 'uploads/cache/';
 }
 }

 //Set the cache directory
 public function set_cache($cache='')
 {
 if (!emptyempty($cache))
 {
 $this->cache = $cache;
 }
 }
 /*
 * Get the remote image and store the file in the cache folder
 *
 * $url Get the remote file The link
 * $error
 * @return 777 returns that the folder cannot be created
 * @return the file name stored in the cache
 */
 public function get_file($url,$error=777)
 {
 $path = $ this->build_folder($this->cache);
 if($path==false) return $error;

 $curl = curl_init();
 // Set the url you need to crawl
 curl_setopt($ curl, curlopt_url, $url);
 // Set header
 curl_setopt($curl, curlopt_header, 0);
 // Set curl parameters to ask whether the result is saved in a string or output to the screen.
 curl_setopt($curl, curlopt_returntransfer, 1);
 // Run curl and request the web page
 $file = curl_exec($curl);
 // Close the url request
 curl_close($curl);

 //Write the file Obtained data
 $filename = $this->cache.date("ymdhis");
 if(self::build_file($file, $filename)==false)
 {
 return false;
 }
 return $ filename;
 }

 //Create a folder
 public function build_folder($dir)
 {
 if (!is_dir($dir))
 {
 if (!mkdir($dir,0777,true) || !chmod ($dir,0777))
 {
 return false;
 }
 }
 return true;
 }

 /*
 * Move files to simulate PHP's move_uploaded_file method
 *
 * $cache cache file path
 * $filename required The absolute path of the generated file name
 *
 * @return $filename
 */
 public function move_file($cache,$filename)
 {
 $file = @file_get_contents($cache);
 if(self::build_file( $file, $filename)==false)
 {
 return false;
 }
 unlink($cache); //Clear cached images
 return $filename;
 }

 /*
 * Generate file
 * $file required The file or binary stream to be written
 * $newname is the absolute path of the file name to be generated
 */
 protected static function build_file($file,$filename)
 {
 $write = @fopen($filename,"w") ;
 if($write==false)
 {
 return false;
 }
 if(fwrite($write,$file)==false)
 {
 return false;
 }
 if(fclose($write)= =false)
 {
 return false;
 }
 return true;
 }
}