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<b>Warning</b>:  session_start(): open(/var/lib/php/sessions/sess_m9g4041jik8kk842q0iscaj561, O_RDWR) failed: No space left on device (28) in <b>/var/www/tb-usercake/models/config.php</b> on line <b>51</b><br />
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<b>Warning</b>:  session_start(): Failed to read session data: files (path: /var/lib/php/sessions) in <b>/var/www/tb-usercake/models/config.php</b> on line <b>51</b><br />
  // retrieves url with HEAD. returns content length,
  // or -1 in case of error.
  public static long getURLSizeByHEAD(String url) {
    if (!url.contains("//")) url = "http://" + url;
      
    HttpURLConnection conn = null;
    try {
      conn = (HttpURLConnection) new URL(url).openConnection();
      conn.setRequestMethod("HEAD");
      conn.getInputStream();
      return conn.getContentLength();
    } catch (IOException e) {
      return -1;
    } finally {
      conn.disconnect();
    }
  }