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What is a session? Why does every website need sessions?
When you visit a website and log in to your account, have you ever wondered, "How does the website know who I am every time I switch pages?" The answer lies in a very common mechanism – Session.
A session is an important part of maintaining user state on a website.
What is a session?
A session is the period of time during which a user interacts with a website, from the moment they access it until they leave. During that time, sessions help remember temporary information such as login status, shopping cart contents, or user preferences.
Easy-to-understand example:
When you visit an e-commerce website, add products to your cart, and proceed to checkout, a session is what remembers the products you selected. Without a session, all information would be lost when you switch pages.
How do sessions work?
The mechanism of a session works as follows:
- The user sends the first request to the server (e.g., login).
- The server creates a Unique Session ID, store user information, and send this ID back to the browser in the form of a cookie.
- In subsequent interactions, the browser sends the Session ID back to the server so it can recognize the correct user.
Sessions help maintain continuity throughout the browsing process, which is not supported by the HTTP protocol by default.
Why websites need to use sessions
Sessions are essential in many situations:
- Remember login status without requiring repeated logins
- Saving shopping cart items for customers during the shopping process
- Maintaining data in multi-step forms
- Record user visits to analyze behavior
Sessions in popular programming languages
- PHP: Use $_SESSION to store and retrieve session data.
- Node.js (Express): Use the express-session library to set up sessions easily.
- Next.js or React: Sessions are managed through APIs or authentication libraries such as next-auth.
Why should programmers care about sessions?
Understanding and using sessions correctly helps you:
- Build security features such as login and access control
- Optimize user experience by keeping everything consistent
- Limit logic errors caused by state loss
Conclusion
Sessions are an essential element when developing websites with user interaction. From maintaining login status to storing shopping cart information, sessions provide a seamless, secure, and convenient experience.
At vietswiss, we apply sessions in all projects, from simple to complex, ensuring that users always feel "accompanied" when using the product.