Python master skills: perfect analysis of cookie acquisition and management

Article directory

- 1. Cookie acquisition in HTTP request
- 2. Cookie acquisition in Web framework
- 3. Use of Cookie Management Library
- 4. Simulated login and cookie authentication
- 5. Handling Cookie Expiration and Persistence
- Summarize

In web development, cookies are a common technology used to store and transfer data between web servers and browsers. Cookies typically contain key-value pairs about a user’s session, preferences, and other information. Python provides several ways to obtain and use cookies to achieve greater control and automation of web applications.

This article will introduce in detail the methods of obtaining cookies in Python, including the usage of HTTP requests, web frameworks and cookie management libraries, and provide sample code to demonstrate the practical application of these methods.

1. Cookie acquisition in HTTP request

When using Python to make web requests, you can use the standard library and third-party libraries to obtain the cookies returned by the web server.

The following is an example using the requests library:

import requests

#Send GET request
response = requests.get("https://example.com")

# Get the cookie returned by the server
cookies = response.cookies

# Print Cookies
for cookies in cookies:
    print(f"Name: {cookie.name}, Value: {cookie.value}")

In the above code, a GET request is first sent, and then response.cookies is used to obtain the cookies returned by the server. Subsequently, iterate over the Cookie object to print the cookie’s name and value.

2. Cookie acquisition in Web framework

If you use a web framework to build a web application, you can usually get and set cookies easily.

Here is an example using the Flask framework:

from flask import Flask, request

app = Flask(__name)

@app.route('/')
def get_cookie():
    # Get the cookie sent by the client
    cookie_value = request.cookies.get('my_cookie')
    return f"Cookie Value: {cookie_value}"

if __name__ == '__main__':
    app.run()

In this example, a simple web application is created using the Flask framework. The value of the cookie named my_cookie can be easily obtained through request.cookies.get('my_cookie').

3. Use of Cookie Management Library

Python also provides some powerful cookie management libraries that can operate cookies more flexibly. A commonly used library is http.cookiejar, which supports the storage, loading and operation of Cookies.

The following is an example using the http.cookiejar library:

import http.cookiejar
import urllib.request

#Create CookieJar object
cookie_jar = http.cookiejar.CookieJar()

#Create HTTPCookieProcessor
cookie_processor = urllib.request.HTTPCookieProcessor(cookie_jar)

# Create Opener
opener = urllib.request.build_opener(cookie_processor)

#Send GET request
response = opener.open("https://example.com")

# Get the cookie returned by the server
for cookie in cookie_jar:
    print(f"Name: {cookie.name}, Value: {cookie.value}")

In this example, a CookieJar object is created using http.cookiejar.CookieJar(), and then a processor is created using urllib.request.HTTPCookieProcessor that can handle cookies. . By creating an Opener and sending a GET request, you can get the cookies returned by the server and iterate over them.

4. Simulated login and cookie authentication

Sometimes, it may be necessary to simulate logging into a website and continue to use cookies for authentication after logging in. This usually involves submitting a username and password to the web server and then using a cookie returned by the server to maintain authentication.

Here is an example that demonstrates how to use the requests library to simulate a login and use cookies for authentication:

import requests

# Build login request
login_data = {<!-- -->
    'username': 'your_username',
    'password': 'your_password'
}

# Send POST request to log in
login_response = requests.post("https://example.com/login", data=login_data)

# Get cookies after login
auth_cookies = login_response.cookies

# Use the logged-in cookie for subsequent requests
profile_response = requests.get("https://example.com/profile", cookies=auth_cookies)

# Output user information
print(profile_response.text)

In this example, a POST request is first constructed to submit a username and password to the web server to log in. Then, the post-login cookies are obtained and passed on to subsequent requests to maintain authentication.

5. Handling Cookie Expiration and Persistence

Cookies may have expiration times, so expired cookies need to be checked and deleted regularly. In addition, cookies can be persisted to a file so that they can be loaded the next time they are used.

The following is sample code that demonstrates how to handle cookie expiration and persistence:

import http.cookiejar
import urllib.request

#Create CookieJar object
cookie_jar = http.cookiejar.CookieJar()

#Create HTTPCookieProcessor
cookie_processor = urllib.request.HTTPCookieProcessor(cookie_jar)

# Create Opener
opener = urllib.request.build_opener(cookie_processor)

#Send GET request
response = opener.open("https://example.com")

# Get the cookie returned by the server
for cookie in cookie_jar:
    print(f"Name: {cookie.name}, Value: {cookie.value}")

# Delete expired cookies
cookie_jar.clear_expired_cookies()

# Save cookies to file
cookie_file = "my_cookies.txt"
cookie_jar.save(cookie_file)

# Load cookies from file
loaded_cookie_jar = http.cookiejar.MozillaCookieJar(cookie_file)
loaded_cookie_jar

.load()

# Make requests using loaded cookies
loaded_opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(loaded_cookie_jar))
loaded_response = loaded_opener.open("https://example.com")

# Output loaded cookies
for cookie in loaded_cookie_jar:
    print(f"Name: {cookie.name}, Value: {cookie.value}")

In this example, first obtain the cookies returned by the server, and then use the clear_expired_cookies() method to delete expired cookies. Next, save the cookies to a file and load them for use in future requests.

Summary

Python’s capabilities are not limited to data processing and algorithms, it is also an excellent network programming tool, especially in web development. Cookies are an integral part of web development, used to store and transmit user information to enable a variety of functions, from authentication to saving user preferences.

Through HTTP requests, you can use third-party libraries such as requests to obtain cookies from the web server. For web frameworks such as Flask, cookies sent by the client can be easily accessed. Python also provides a cookie management library, such as http.cookiejar, which allows storing, loading and operating cookies, providing more control.

In short, knowing how to obtain and use cookies is an important skill in web development. These cookie acquisition methods can help you better grasp user data, maintain authentication status, and provide a better user experience. Whether you are developing web applications or web scraping, Python’s cookie handling skills will be of great help.

Interested friends will receive a complete set of Python learning materials, including interview questions, resume information, etc. See below for details.

1. Python learning routes in all directions

The technical points in all directions of Python have been compiled to form a summary of knowledge points in various fields. Its usefulness is that you can find corresponding learning resources according to the following knowledge points to ensure that you learn more comprehensively.

2. Python essential development tools

The tools have been organized for you, and you can get started directly after installation!

3. Latest Python study notes

When I learn a certain basic and have my own understanding ability, I will read some books or handwritten notes compiled by my seniors. These notes record their understanding of some technical points in detail. These understandings are relatively unique and can be learned. to a different way of thinking.

4. Python video collection

Watch a comprehensive zero-based learning video. Watching videos is the fastest and most effective way to learn. It is easy to get started by following the teacher’s ideas in the video, from basic to in-depth.

5. Practical cases

What you learn on paper is ultimately shallow. You must learn to type along with the video and practice it in order to apply what you have learned into practice. At this time, you can learn from some practical cases.

6. Interview Guide

Resume template

If there is any infringement, please contact us for deletion.