捕获Server运行期致命错误

Server运行期一旦发生致命错误，那客户端连接将无法得到回应。如Web服务器，如果有致命错误应当向客户端发送Http 500 错误信息。

在PHP中可以通过register_shutdown_function + error_get_last 2个函数来捕获致命错误，并将错误信息发送给客户端连接。具体代码示例如下：

register_shutdown_function('handleFatal');
function handleFatal()
{
    $error = error_get_last();
    if (isset($error['type']))
    {
        switch ($error['type'])
        {
        case E_ERROR :
        case E_PARSE :
        case E_CORE_ERROR :
        case E_COMPILE_ERROR :
            $message = $error['message'];
            $file = $error['file'];
            $line = $error['line'];
            $log = "$message ($file:$line)\nStack trace:\n";
            $trace = debug_backtrace();
            foreach ($trace as $i => $t)
            {
                if (!isset($t['file']))
                {
                    $t['file'] = 'unknown';
                }
                if (!isset($t['line']))
                {
                    $t['line'] = 0;
                }
                if (!isset($t['function']))
                {
                    $t['function'] = 'unknown';
                }
                $log .= "#$i {$t['file']}({$t['line']}): ";
                if (isset($t['object']) and is_object($t['object']))
                {
                    $log .= get_class($t['object']) . '->';
                }
                $log .= "{$t['function']}()\n";
            }
            if (isset($_SERVER['REQUEST_URI']))
            {
                $log .= '[QUERY] ' . $_SERVER['REQUEST_URI'];
            }
            error_log($log);
            $serv->send($this->currentFd, $log);
        default:
            break;
        }
    }
}