课程相关资料下载地址

作者回复: 因为http请求被TLS加密了，wireshark作为中间人无法解密出http格式的消息。第3部分第3课会介绍wireshark如何解密chrome中的TLS消息

作者回复: 比较复杂，根据资源类型、隐私策略、各浏览器的设计哲学等而定，例如chrome官方文档曾经这么描述：“Chrome employs two caches — an on-disk cache and a very fast in-memory cache. The lifetime of an in-memory cache is attached to the lifetime of a render process, which roughly corresponds to a tab. Requests that are answered from the in-memory cache are invisible to the web request API. If a request handler changes its behavior (for example, the behavior according to which requests are blocked), a simple page refresh might not respect this changed behavior. To make sure the behavior change goes through, call handlerBehaviorChanged() to flush the in-memory cache. But don't do it often; flushing the cache is a very expensive operation. You don't need to call handlerBehaviorChanged() after registering or unregistering an event listener.”

作者回复: 虽然缓存已经过期，但client想问问看过期的缓存能不能用，因为server如果发现资源到现在仍然没变化，那么缓存就仍然可以用，因为304要比200有效率多了，通常http body都要远大于header

作者回复: 是的，你的理解是对的

作者回复: 指纹是实时生成的，比如文件大小+最后访问时间