HTTP请求头和响应头详解

Genenral

Request URL: https://i.forudesigns.cn/api/v1/business/admin
Request Method: GET
Status Code: 200 
Remote Address: 47.96.227.110:443
Referrer Policy: strict-origin-when-cross-origin

Response Headers

access-control-allow-headers: *, x-requested-with, origin, authorization, x-foru-session, x-foru-business-domain, content-type, accept
access-control-allow-methods: GET, POST, PUT, DELETE, OPTIONS
access-control-allow-origin: *
cache-control: no-cache, private
content-encoding: gzip
content-type: application/json
date: Mon, 30 Nov 2020 04:00:42 GMT
server: nginx
strict-transport-security: max-age=63072000; includeSubdomains; preload
vary: Accept-Encoding
x-execution-time: 58ms

Request Headers

:authority: i.forudesigns.cn
:method: GET
:path: /api/v1/business/admin
:scheme: https
accept: application/json, text/plain, */*
accept-encoding: gzip, deflate, br
accept-language: en
origin: http://127.0.0.1:3000
referer: http://127.0.0.1:3000/
sec-fetch-dest: empty
sec-fetch-mode: cors
sec-fetch-site: cross-site
user-agent: Mozilla/5.0 (iPhone; CPU iPhone OS 13_2_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.3 Mobile/15E148 Safari/604.1

cache-control:

public 任何客户端, 包括中间代理, 比如cdn
private 浏览器
no-cache 不建议缓存,每次请求需要与服务器验证是否过期
no-store, 不要缓存
max-age, 缓存时间,从第一次请求时间开始计算, 单位为s
immutable, 在有效期内,不会发生变化

不要缓存, 同时清空旧缓存 Cache-Control: no-store, max-age=0
允许各种客户端缓存内容 Cache-Control: public, max-age=604800, immutable [在604800 seconds = 7 days, 文件不会发生变化, 这期间内不用再发额外请求与服务端验证]

Accept-Encoding

解码

Origin 和 referer

Origin 请求发起

Referer 来源-可用于防盗链

Connection = keepalive

如果要在HTTP1.0中支持keep alive，你必须明确的在header中加入Connection:keep-alive。

1.client 发起一个包含Connection:keep-alive的请求

2.server收到请求后，如果server支持keepalive，回复一个包含Connection:keep-alive的响应，不关闭连接，否则回复一个包含Connection:close的响应，关闭连接。

3.如果client收到包含Connection:keep-alive的响应，向同一个连接发送下一个请求，直到一方主动关闭连接。

因为keepalive在很多情况下能够重用连接，减少资源消耗，缩短响应时间。所以在HTTP1.1中缺省就是支持keepalive的，如果响应方不支持keepalive,需要明确的标识Connection:close，Connection:keep-alive就没什么意义了。