public static function extractHeaders($response_str)
    {
        $headers = array();

        // First, split body and headers
        $parts = preg_split('|(?:\r?\n){2}|m', $response_str, 2);
        if (! $parts[0]) return $headers;

        // Split headers part to lines
        $lines = explode("\n", $parts[0]);
        unset($parts);
        $last_header = null;

        foreach($lines as $line) {
            $line = trim($line, "\r\n");
            if ($line == "") break;

            // Locate headers like 'Location: ...' and 'Location:...' (note the missing space)
            if (preg_match("|^([\w-]+):\s*(.+)|", $line, $m)) {
                unset($last_header);
                $h_name = strtolower($m[1]);
                $h_value = $m[2];

                if (isset($headers[$h_name])) {
                    if (! is_array($headers[$h_name])) {
                        $headers[$h_name] = array($headers[$h_name]);
                    }

                    $headers[$h_name][] = $h_value;
                } else {
                    $headers[$h_name] = $h_value;
                }
                $last_header = $h_name;
            } elseif (preg_match("|^\s+(.+)$|", $line, $m) && $last_header !== null) {
                if (is_array($headers[$last_header])) {
                    end($headers[$last_header]);
                    $last_header_key = key($headers[$last_header]);
                    $headers[$last_header][$last_header_key] .= $m[1];
                } else {
                    $headers[$last_header] .= $m[1];
                }
            }
        }

        return $headers;
    }