The difference between session and cookie

Preface

In school , Students need a student ID to enter the school （ If it is the first time to enter school , Will give you a student card , That is, it will create a cookie）, The student ID here is equivalent to a cookie, Of course ,cookie There can be multiple , Security staff （ The server ） See you have a student ID , You are allowed to enter the school .

If you don't want to pass the student ID these things （cookie） To get into school , You can register information （session）, The security guard will record you （ There will be one. sessionID, The only user ）, In this way, if you want to enter the school in the future, you can pass the registration information （sessionID） To get into school .

Common ground

cookie and session Are used to identify the conversation mode of browser users .

（ conversation ： You open a browser , Click on multiple hyperlinks , The whole process from closing the browser can be called a session ）

difference

• cookie The data is saved on the client side ,session Data is saved on the server side .
• cookie The action time of can be called setMaxAge Method to set the validity period , Even if the session is closed, it is still valid .session The function time of is that the session ends when it is closed .
• cookie Not very safe , Can analyze the data stored locally COOKIE And carry on COOKIE cheating , If the main consideration is to save important information , Should be used session.
• because session It will remain until the session ends , So when there are a lot of visits , Will affect performance , If you consider reducing server performance , Should be used cookie.