cookie
https://www.nczonline.net/blog/2009/05/05/http-cookies-explained/
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Cookie
small files of information that a web server generates and sends to a web browser.
key/value pairs used by websites to store state information on the browser.
cookie 流程
1, 访问
GET /index.html HTTP/1.1
Host: www.example.com
2, 返回
HTTP/1.1 200 OK
Content-type: text/html
Set-Cookie: foo=10
Set-Cookie: bar=20; Expires=Fri, 30 Sep 2011 11:48:00 GMT
... rest of the response
3, 后续访问
GET /spec.html HTTP/1.1
Host: www.example.com
Cookie: foo=10; bar=20
Accept: */*
SESSIONS:
Server side cookies
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