When a website sets a cookie, it includes a key-value pair that is stored on the user’s computer. The website can then access this data when the user visits the website again in the future. For example, a website might set a cookie to remember a user’s language preference, so that the website can automatically display content in the appropriate language.
Session cookies, also known as temporary cookies, are stored in the browser’s memory and are only available for the duration of the user’s session. This means that when the user closes their browser or logs out of the website, the session cookie is deleted.
Session cookies are commonly used for authentication and tracking user activity on a website. For example, session cookies can be used to keep a user logged in while they navigate through different pages of a website.
Persistent cookies, also known as permanent cookies, are stored on the user’s computer even after they close their browser. This means that the cookie remains on the user’s computer until it expires or the user manually deletes it.
Persistent cookies are commonly used for things like remembering user preferences, such as language or location settings, and for tracking user behavior over time. They can also be used for advertising and marketing purposes.
- Using cookie prefixes: By prefixing your cookies with a custom string, you can avoid conflicts with cookies set by other sites and ensure that your cookies are unique and easy to identify.
- Encoding data in cookies: Cookies are typically limited to storing plain text data, but you can use techniques like base64 encoding to store more complex data types.
- Setting expiration dates: By setting expiration dates for your cookies, you can control how long they persist on the user’s device and ensure that they don’t remain indefinitely.
- Handling cookie deletion: When a user logs out or clears their cookies, you may need to perform additional cleanup tasks to ensure that any associated data is also removed from your system.
By implementing these techniques, you can take greater control over how your cookies are used and ensure that your site remains fast, scalable, and secure.
- Keep it Simple: Keep the cookies simple and use them only for essential purposes. Avoid using cookies for non-essential functions such as advertising or tracking user behavior without their consent.
- Always Use Secure Cookies: It is important to use secure cookies using SSL encryption to ensure that the cookies are not tampered with in transit.
- Keep Cookies Small: Keep the cookie size as small as possible to reduce the impact on website performance and reduce the risk of cookie theft.
- Set Expiration Dates: Set expiration dates for cookies so that they are automatically deleted when they are no longer needed. This reduces the risk of stale cookies being used for malicious purposes.
- Provide an Option to Opt-out: Provide users with an option to opt-out of cookies, and make sure that your website works properly even if the user opts-out of cookies.
- Forgetting to set the domain and path: When a cookie is created, you need to specify the domain and path to which it belongs. If you don’t set these values, the cookie will not be accessible to other pages on the same domain.
- Setting the wrong expiration date: Cookies can be set to expire after a specific period or when the user closes the browser. If you set the wrong expiration date, the cookie may be deleted too soon or not deleted at all, causing unexpected behavior.
- Not escaping special characters: Cookies can contain special characters such as commas, semi-colons, and white spaces. If you don’t escape these characters properly, it can cause issues when reading the cookie value.
- Using an invalid cookie name: Cookie names must follow specific rules, such as not containing spaces or special characters. If you use an invalid cookie name, the cookie may not be saved or retrieved correctly.
- Not checking if cookies are enabled: Some users may disable cookies on their browsers, which can cause issues if your application relies heavily on cookie functionality. Always check if cookies are enabled before using them.
By avoiding these common errors, you can ensure that your cookies work as intended and your web application runs smoothly.
- Always set cookie expiration date: When you set a cookie without an expiration date, it becomes a session cookie, and it will expire once the user closes the browser. Always set an expiration date to avoid unexpected cookie deletion.
- Store only essential data in cookies: Cookies should be used to store small amounts of data, such as session IDs or user preferences. Do not store sensitive information such as passwords or credit card details.
- Implement a cookie consent banner: Before setting any cookies, it is essential to get the user’s consent. Implement a cookie consent banner that explains what cookies are used on your website and gives users the option to accept or reject them.
- Use a cookie library: Instead of writing cookie management code from scratch, use a cookie library that provides a simple API to set, get, and delete cookies. Some popular libraries include js-cookie and jquery-cookie.
By implementing the tips and tricks mentioned above, you can ensure that your web application is safe, secure, and compliant with data privacy regulations such as GDPR and CCPA.