Cookie (HTTP)

Cookies Basics

Cookies, formally known as HTTP cookies, are text files with small pieces of information that are stored on a web browser (Mozilla 2021). These small pieces of information are usually in the form of name-value pairs. The information that a cookie is composed of is sent by the server along with the response to the request sent by the web browser. The browser stores this information in the form of a cookie and sends it back to the same server with the later requests (Mozilla 2021). This helps the server identify if the two requests are coming from the same browser.

Applications of Cookies

Cookies are used for remembering stateful information for logins and other purposes in the stateless HTTP protocol. The uses of cookies can be categorized into three broad categories.

First, cookies are useful for session management. A website might generate a unique ID number for each visitor and store that ID number on each user's machine using a cookie file. One way that cookies are useful is that “they can be used for shopping carts on e-commerce sites” (Moraes 2020). Cookies are used for ensuring that the user is logged in for the entire session. It also helps in remembering the shopping carts, game scores, and other data within a session (Moraes 2020).

Cookies are also helpful for user personalization on a web browser (Mozilla 2021). Cookies are helpful in remembering user preferences, themes, and other settings which makes it easy for users to configure page settings.

Another common way that cookies can be used for tracking activity. Cookies are used for tracking users’ browsing behaviors and by websites to recommend products or send advertisements based on browsing history (Mozilla 2021).

Cookie Lifespan

Session cookies are typically deleted when the session ends. The session start time and session end time is usually determined by the browser, which is based on the user activity. For permanent cookies, their lifespan is based on an expiration date and time. These types of cookies have a predetermined expiration date and time and that’s when they are deleted from the browser.

To forcefully remove, or pop, a cookie, you should set the cookie attribute max_age to 0 in the decorator function that does this. The code below shows how to do this for a general cookie using Flask's make_response and set_cookie functions:

@app.route('/delete-cookie/')

def delete_cookie():

    res = make_response("Your_desired_message")

    res.set_cookie('foo
@app.route('/delete-cookie/')
def delete_cookie():
  res = make_response('Your desired message')
  res.set_cookie('foo', 'bar', max_age=0)
  return res

Cookies in various Web Frameworks

Flask

See Cookies in Flask for a detailed explanation of how to do this in flask

References

Web Links

Note Links