Today we’re going to talk about cookies and cookie jars in Python web development projects. Cookies are small text files that websites store on our computers to remember who we are and where we left off last time we visited them. But how do they actually work? That’s where cookie jars come in!
A cookie jar is a class provided by the Python standard library to manage cookies for HTTP requests and responses. It allows us to store, retrieve, and delete cookies from our web browser sessions. There are two popular subclasses of CookieJar that we can use with Mozilla and LWP: the MozillaCookieJar and the LWPCookieJar!
The MozillaCookieJar is based on the CookieManager from Mozilla, which means it can be used with Firefox or any other browser that supports this feature (like Chrome). To use it in Python, we simply import the module and create a new instance of the class:
# Import the MozillaCookieJar module from the cookielib library
from cookielib import MozillaCookieJar
# Create a new instance of the MozillaCookieJar class and assign it to the variable cj
cj = MozillaCookieJar()
That’s all there is to it! Now you can store cookies using the `.set_cookie()` method, retrieve them with `.get_cookies()`, and delete them by passing a list of cookie names:
# This script is used to demonstrate how to store, retrieve, and delete cookies using the `set_cookie()`, `get_cookies()`, and `remove_cookie()` methods.
# First, we import the necessary module for handling cookies.
import http.cookiejar as cookiejar
# Next, we create a cookie jar object to store our cookies.
cj = cookiejar.CookieJar()
# We use the `set_cookie()` method to add a cookie to our cookie jar.
# The first argument is the domain of the website, and the second argument is the cookie itself.
# In this case, we are setting a cookie with the name "name" and the value "John" for the domain "example.com".
cj.set_cookie('example.com', 'name=John')
# We use a for loop to iterate through all the cookies in our cookie jar.
# The `get_cookies()` method returns a list of all the cookies in the jar.
for cookie in cj.get_cookies():
# We use string formatting to print out the name and value of each cookie.
# The `cookie` variable is a dictionary with the keys "name" and "value".
print(f'{cookie["name"]}={cookie["value"]}')
# Finally, we use the `remove_cookie()` method to delete a specific cookie from our cookie jar.
# The argument for this method is a dictionary with the domain and path of the cookie we want to remove.
# In this case, we are removing a cookie with the domain "example.com" and the path "/".
cj.remove_cookie({"domain": "example.com", "path": "/"})
The MozillaCookieJar also supports cookie expiration and domain restrictions:
# Set a cookie that expires in 1 day (86400 seconds)
# cj is a MozillaCookieJar object that supports cookie expiration and domain restrictions
# set_cookie() is a method that adds a cookie to the jar
# 'example.com' is the domain for which the cookie is being set
# 'name=John' is the cookie value
# {'Expires': 'Wed, 25 Dec 2037 23:59:59 GMT'} is a dictionary containing the expiration date for the cookie
cj.set_cookie('example.com', 'name=John', {'Expires': 'Wed, 25 Dec 2037 23:59:59 GMT'})
# Set a cookie that is only valid for the domain "www.example.com" and its subdomains
# 'www.example.com' is the specific domain for which the cookie is being set
# 'name=John' is the cookie value
# {'Domain': '.example.com'} is a dictionary containing the domain restriction for the cookie
cj.set_cookie('www.example.com', 'name=John', {'Domain': '.example.com'})
On the other hand, LWPCookieJar is based on the Cookie class from Perl’s libwww-perl module (hence its name). This subclass can be used with any web browser that supports HTTP/1.0 or later, including Python’s built-in urllib library:
# Import the LWPCookieJar class from the cookielib module
from cookielib import LWPCookieJar
# Create an instance of the LWPCookieJar class and assign it to the variable cj
cj = LWPCookieJar()
The syntax for setting and retrieving cookies is similar to MozillaCookieJar, but there are some differences in the way they handle expiration times and domain restrictions:
# Set a cookie that expires after 1 day (86400 seconds)
# cj is a variable representing a cookie jar object
# set_cookie() is a method used to set a cookie in the cookie jar
# 'example.com' is the domain for which the cookie is being set
# 'name=John' is the cookie value
# {'Expires': 'Wed, 25 Dec 2037 23:59:59 GMT'} is a dictionary containing the expiration time for the cookie
# The expiration time is set to 25 Dec 2037 at 23:59:59 GMT
cj.set_cookie('example.com', 'name=John', {'Expires': 'Wed, 25 Dec 2037 23:59:59 GMT'})
# Set a cookie that is only valid for the domain "www.example.com" and its subdomains
# 'www.example.com' is the specific domain for which the cookie is being set
# 'name=John' is the cookie value
# {'Domain': '.example.com'} is a dictionary containing the domain restriction for the cookie
# The cookie will only be valid for the domain "www.example.com" and any of its subdomains
cj.set_cookie('www.example.com', 'name=John', {'Domain': '.example.com'})
Both MozillaCookieJar and LWPCookieJar offer similar functionality for managing cookies in Python, but they have some differences in terms of syntax and compatibility with different web browsers or HTTP libraries. So which one should you use? Well, that depends on your specific needs! If you’re working with Firefox or other Mozilla-based browsers, go ahead and use the MozillaCookieJar. But if you prefer Python’s built-in urllib library (or any other HTTP/1.0+ compatible browser), LWPCookieJar might be a better fit for your project.