Sessions, Cookies, and State in PHP
Sessions, cookies and state in PHP enable a website to remember users and their actions across different pages. Because PHP runs over HTTP, which itself is a stateless protocol, web sites have to use a trick in order to remember people‘s login, preferences, and where they‘ve been.
Without sessions & cookies as you visit different pages of the site, it would be as if it‘s your first visit. So users won‘t be able to login or experience customizations.
Why State Management Is Important in PHP
State management enables the PHP application to persist across requests. For instance, a web application requires the server to remember that a person has already logged in when he switches to another page from the one where he first logged in.
This issue is solved in PHP with the use of following things; sessions and cookies. The data stored in each way one of different. But both have optimised way to handle state in PHP. So in order to develop real application on PHP knowledge of state is required.
Overview of Sessions and Cookies
States managed by PHP are controlled using two main utilities; Here is a list of these two main utilities
Sessions keep user data on the server associated with a unique session id. It protects sensitive data and works well for login systems.
What the cookie does is save small data bits to the users’ browser. Usually used for preferences and small data bits by developers.
These concepts will be defined more thoroughly with examples and best practices in the following sections.
Use Cases of Sessions, Cookies, and State in PHP
Sessions, cookies and state management is what is used whenever you visit a site and it is supposed to remember something about you. They turn a website into more than just a static page.
User Login and Authentication
In order to keep a user signed in when navigating across pages, you need to maintain state. Sessions take care of this: They store login information on the server so that it is secure.
Maintaining User Preferences
Many times websites remember the language, theme or layout of the site. Cookies are perfect as they can hold small preference data to be stored within the browser.
Shopping Carts and Orders
Ecommerce sites must track products in a shopping cart. During browsing different pages, sessions allow the cart data to be stored until the user reaches checkout.
Form Data Across Pages
Can happen, and may distribute across multiple pages. State management maintains any input the user has entered so it doesn‘t get lost while moving through the sequence.
Personalized Content
Websites display customized messages, recommendations or dashboards depending on the past behavior of the user. The user‘s session and cookie combination is used to achieve this.
Tracking User Activity
Websites may also keep tabs of page visits or things you have recently looked at in order to improve usability. This type of tracking is usually handled by cookies.
Why These Use Cases Matter
Without sessions, cookies, and state management, users would need to log in repeatedly and reenter information on every page. As a result, websites would feel slow and frustrating to use.
The use cases above are only meant to give a beginner an idea of when and why he or she would want to use sessions or cookies in a real PHP project.
Summary
Sessions, cookies and state in PHP are used to solve the problem of remembering the user through multiple page requests. Sessions contain data on the webserver stored securely, and cookies are stored in the browser with limited data. Use of these allows PHP to create dynamic web experiences.
