On cookies and session

Catalog

Cookie

（1） Format ：

（2） effect ：

（3） principle ：

（4） Application scenarios ：

Session

（1） Concept

（2） effect

（3） principle

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Cookie

（1） Format ：

Standard request header ：cookie： key = value

Standard response header ：set-cookie: Key value

（2） effect ：

cookie It is used to save information （ Client local , Browser related folders ）

（3） principle ：

（4） Application scenarios ：

User login free （remember me)

① Enter the account and password , Check login free  

② Click the login button , send out http request , Server return http Respond to

③ The browser automatically saves “ User information ” On the local hard disk , Every time I ask , Request headers carry cookie： User information

（ Turn off the browser in time , Visit this again url, Will also carry ）

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Session

（1） Concept

conversation , Indicates after login , Before cancellation , And there is no timeout between the last operation and the next operation （ Specified conversation time ） It's all a conversation .

（2） effect

Identify the valid user who logged in

（3） principle

The server saves user information （ When logging in, verify that the account and password pass , Save user information ）, When accessing sensitive resources , User information saved through the server , Determine whether to log in , Whether to allow access to .