EDIT

    $header['Accept'] = (variable_get('cdm_webservice_type', 'json') == 'json' ? 'application/json' : 'text/xml');

  if (FALSE && function_exists('curl_init')) {

    // !!!!! CURL Disabled due to problems with following redirects

    // (CURLOPT_FOLLOWLOCATION=1) and safe_mode = on

    // Use the CURL lib if installed, it is supposed to be 20x faster.

    return _http_request_using_curl($uri, $header, $method, $parameters);

  }

  else {

    return _http_request_using_fsockopen($uri, $header, $method, $parameters);

  }

}

/**

 * @todo Please document this function.

 * @see http://drupal.org/node/1354

 */

function _http_request_using_fsockopen($uri, $header = array(), $method = 'GET') {

/**

 * Return string content from a remote file.

 *

 * @author Luiz Miguel Axcar <lmaxcar@yahoo.com.br>

 *

 * @param string $uri

 *   The url for which to return content.

 *

 * @return string

 *   The returned content.

 */

function _http_request_using_curl($uri, $headers = array(), $method = "GET", $parameters = array()) {

  $ch = curl_init();

  curl_setopt($ch, CURLOPT_URL, $uri);

  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);

  curl_setopt($ch, CURLOPT_MAXREDIRS, 5);

  // Set proxy settings.

  if (variable_get('cdm_webservice_proxy_url', FALSE)) {

    curl_setopt($ch, CURLOPT_PROXY, variable_get('cdm_webservice_proxy_url', ''));

    curl_setopt($ch, CURLOPT_PROXYPORT, variable_get('cdm_webservice_proxy_port', '80'));

    if (variable_get('cdm_webservice_proxy_usr', FALSE)) {

      curl_setopt($ch, CURLOPT_PROXYUSERPWD, variable_get('cdm_webservice_proxy_usr', '') . ':' . variable_get('cdm_webservice_proxy_pwd', ''));

    }

  }

  // Modify headers array to be used by curl.

  foreach ($headers as $header_key => $header_val) {

    $curl_headers[] = $header_key . ': ' . $header_val;

  }

  if (isset($curl_headers)) {

    curl_setopt($ch, CURLOPT_HTTPHEADER, $curl_headers);

  }

  // Set method if not default.

  if ($method != "GET") {

    if ($method == "POST") {

      curl_setopt($ch, CURLOPT_POST, 1);

      curl_setopt($ch, CURLOPT_POSTFIELDS, $parameters);

    }

    else {

      // Other obscure http methods get passed to curl directly.

      // TODO generic parameter/body handling

      curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $method);

    }

  }

  ob_start();

  curl_exec($ch);

  $info = curl_getinfo($ch);

  if (curl_errno($ch)) {

    watchdog('CDM_API', '_http_request_curl() - ' . curl_error($ch) . '; REQUEST-METHOD:' . $method . ' URL: ' . substr($uri . ' ', 0, 150), WATCHDOG_ERROR);

    if (variable_get('cdm_webservice_debug', 1) && user_access('administer')) {

      drupal_set_message(check_plain(t('_http_request_curl() - !curl_error; REQUEST-METHOD:!method URL: !url', array(

      '!curl_error' => curl_error($ch),

      '!method' => $method,

      '!url' => substr($uri . ' ', 0, 150),

       ))), 'error');

    }

  }

  curl_close($ch);

  $string = ob_get_contents();

  ob_end_clean();

  return $string;

}