Have you ever wondered how websites remember your preferences or keep you logged in even after closing your browser? Well, my friends, the secret lies in two powerful tools of web development: cookies and sessions. In this article, we’ll take a deep dive into these fascinating mechanisms and uncover their roles in storing and managing user data. So, fasten your seatbelts and get ready to embark on this exciting journey of difference between cookies and sessions!
Table of Contents
What is a Cookie?
A cookie is an HTTP object on any web browser that stores information of the user accessing any website on the browser. HTTP cookie contains user credentials like the page frequently visited by a user, frequently used keywords used by a user to search an item, items added to the cart and so on. The cookie sends the information to the server and when the next time a user revisits the same page, the information is retrieved from the server. This process makes fetching results faster than a first time visit.
Hence the use of cookie can be summarized as authentication, saving preferences for a website, adding items to the cart, session identification.
Some useful information about a cookie are:
- The way a cookie stores information is through a lookup table that contains a key-value pair. eg. name->phone no.
- Data is written to a cookie when a user clicks on a ‘submit’ or ‘save’ button to save his information at the server. The page responsible for handling that piece of information then saves the value inside a cookie. But there is an exception here, if a user selects to disable cookies, then the write operation would fail.
- Cookies are a good way to communicate user session information from one site across different websites without loading the server with the burden to process each request.
- The duration for which a cookie shall store the user data could be chosen by the end user in settings.
- One can set the root domain for a cookie. With the root domain a cookie shall be accessible to any URL that belongs to the root. For example, cnn.com is set as the root domain then the sub domains that belong to the root could be – www.cnn.com, canada.cnn.com and so on.
- Security of cookies is a prime concern. The information stored in a cookie could very easily be sent to a third party.
What is a Session?
Session is the duration for which a user is logged in to his email account, or a registration page or any such activity where user authentication is required.
A session is categorised as – stateless and stateful.
Stateless session bean is the one which does not maintain session states of a client machine more than the period of a method invocation. Post completion of a certain method call, the instance variable for the same is destroyed.
However, a stateful session bean is the one for which the session state is maintained and only be removed at a user’s discretion.
Session Management Types:
- Desktop Session Management: The desktop session manager saves and stores sessions on a desktop system (Windows, Linux, Ubuntu etc.).
- Browser Session Management: This session management is done within a browser. The session manager stores information like open pages and settings so that the same can be retrieved at a later date. Such data can be used in case of a system or application crash on any browser say Mozilla, Chrome, Opera etc.
- Web Server Session Management: Web session management deals with managing user information over HTTP request and response sessions. This includes web’s method of saving state of a user when he logs in to a site using his login id and password. The data is thus saved at the server and the user shall be granted access each time he tries to access the site.
Difference Between Sessions and Cookies:
Here’s a table explaining the difference between cookies and sessions.
| Cookies | Sessions | |
| 1. Definition | Small pieces of data are stored on the client-side (browser). | Server-side storage that stores user-specific information during a session. |
| 2. Purpose | Tracking user preferences and maintaining state | Managing user sessions and storing temporary data. |
| 3. Storage | Stored on the client-side (browser). | Stored on the server-side. |
| 4. Size Limit | Typically limited to a few kilobytes (4KB – 10KB). | Can store larger amounts of data (varies depending on server configurations). |
| 5. Security | Less secure compared to sessions. | More secure as data is stored on the server, and only a session ID is sent to the client. |
| 6. Expiry | It can be set with an expiration date or time. | It expires when the session ends (typically after a period of inactivity or the browser is closed). |
| 7.Communication | Sent to the server with every request. | The server generates a unique session ID and sends it to the client, which is returned with subsequent requests. |
| 8. Usage | Often used for remembering user preferences or tracking. | Used for user authentication, maintaining user state, and storing temporary data. |
Conclusion:
In conclusion, cookies and sessions are both mechanisms used in web development to store and manage data related to user interactions. Cookies are small pieces of data stored on the client-side (browser) and are commonly used for tracking user preferences and maintaining state. They have size limitations and are less secure compared to sessions.
On the other hand, sessions are server-side storage that stores user-specific information during a session. They are more secure as data is stored on the server, and only a session ID is sent to the client. Sessions can store larger amounts of data and expire when the session ends, typically after a period of inactivity or when the browser is closed.
Cookies are sent to the server with every request, while sessions involve the generation of a unique session ID that is sent to the client and sent back with subsequent requests.
In practice, cookies are often used for remembering user preferences or tracking, while sessions are commonly used for user authentication, maintaining user state, and storing temporary data.
It’s important to note that the specific implementation and usage of cookies and sessions may vary depending on the programming language, framework, and server configurations used.