test.php

<?php
    $url_a = parse_url($base_url . drupal_encode_path($url));
    $fp = fsockopen($url_a['host'], 80, $errno, $errstr, 5);
    if (!$fp) {
      echo "$errstr ($errno)<br />\n";
    } else {
      $out = "GET $url_a[path] HTTP/1.1\r\n";
      $out .= "Host: $url_a[host]\r\n";
      $out .= "Connection: Close\r\n\r\n";
      fwrite($fp, $out);
      while (!feof($fp)) {
        $s = fgets($fp, 128);
        if (strpos($s, 'Content-Type') === 0) {
          $result = explode(';', substr($s, 13));
          $content_type['mime'] = trim(array_shift($result));
          foreach($result as $chunk) {
            $chunk_a = explode('=', $chunk);
            $content_type[$chunk_a[0]] = trim($chunk_a[1]);
          }
          break;
        }
      }
      fclose($fp);
    }
    $content_types[$url] = $content_type;