3. RFC2616 HTTP/1.1概述 The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. RFC2616 21个章节 协议参数、消息、请求、响应、实体、连接、方法、状态码、缓存、Header
11. HTTP缓存 Caching would be useless if it did not significantly improve performance. HTTP/1.1中缓存的目的 尽量减少发送请求的需求,“截止”机制 尽量减少发送完整响应的需求,“证实”机制 缓存的正确性 与原始服务器检查是等效的 “足够新”满足服务器对于更新的需要 适当的304、305或错误(4x,5x)响应消息