Add HTPP Cache Option for googlePlus

[ewwink]

Too many (Million lol) HTTP request to googlePlus may decrease your server performance or even you get blocked, here I modify sharrre.php you only need to define cache life, by default it used 5 minutes and make sure sharrre-cache directory is exist and writable.

Change original code from

  $contents = parse('https://plusone.google.com/u/0/_/+1/fastbutton?url=' . $url . '&count=true');
  preg_match( '/window\.__SSR = {c: ([\d]+)/', $contents, $matches ); 
  if(isset($matches[0])){ 
      $json['count'] = (int)str_replace('window.__SSR = {c: ', '', $matches[0]); 
  }

with

if (!file_exists("sharrre-cache")) {
      mkdir("sharrre-cache");         
  } 
  $cache_file = "sharrre-cache/".base64_encode($_GET['url']);
  // cache for 5 minutes
  if (file_exists($cache_file) && (filemtime($cache_file) > (time() - 60 * 5 ))) {
      $file = file_get_contents($cache_file);
      $json['count'] = $file;
  } else {
      $contents = parse('https://plusone.google.com/u/0/_/+1/fastbutton?url=' . $url . '&count=true');
      preg_match( '/window\.__SSR = {c: ([\d]+)/', $contents, $matches );
      if(isset($matches[0])){
          $json['count'] = (int)str_replace('window.__SSR = {c: ', '', $matches[0]);
          file_put_contents($cache_file, $json['count'], LOCK_EX);
      }
      else{
          file_put_contents($cache_file, "0", LOCK_EX);
      }

  }