Web Scraping & Bots · Lesson

Handling User Authentication

Build bots that can log in to websites using credentials, session management, and cookie handling.

Handling User Authentication is a free Web Scraping & Bots lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Web Scraping & Bots learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Why Bots Need to Log In

Many websites require you to log in to access certain data or features. Bots often need to simulate this process to get past paywalls, access dashboards, or retrieve personalized content.

Access restricted content.
Perform user-specific actions.
Maintain a persistent identity.

Understanding Login Forms

When you log in manually, your browser sends your username and password to the server. This is usually done via an HTTP POST request to a specific URL.

POST request: Sends data securely in the request body.
Form fields: Input fields for credentials (e.g., username, password).
Action URL: The server endpoint that processes the login.

Finding Login Form Details

To automate a login, you need to identify the form's action URL and the name attributes of the input fields (username, password). Browser developer tools are essential here.

Right-click on the login form → "Inspect".
Look for the <form> tag: find its action attribute.
Look for <input> tags: find their name attributes for credentials.

Sending Login Data with Requests

The Python requests library can send POST requests. You'll prepare a dictionary of your credentials and pass it to requests.post().

The dictionary keys should match the input field name attributes.
The values will be your username and password.
The url will be the form's action URL.

Basic Login Attempt

Here's a simple example of trying to log in. Note that without session management, you'll likely be logged out immediately after the request, as no cookies are persisted.

import requests

login_url = "http://httpbin.org/post" # Example URL
credentials = {
    "username": "my_user",
    "password": "my_password"
}

response = requests.post(login_url, data=credentials)

print(f"Status Code: {response.status_code}")
print("Response data (simulated):")
print(response.json().get('form'))

Sessions & Cookies for Persistence

After a successful login, websites typically send back a cookie. This small piece of data is stored by your browser and sent with subsequent requests, telling the server you're still logged in.

Session: A continuous interaction between a user and a website.
Cookies: Small text files used by websites to remember information about you.
Crucial for maintaining a logged-in state across multiple page visits.

Managing Sessions with `requests.Session()`

The requests library has a Session object that automatically handles cookies for you. Once you log in using a Session object, it will include the authentication cookies in all subsequent requests made through that same session.

Create a session object: s = requests.Session().
Use s.post() for login and s.get() for subsequent requests.
No need to manually manage cookies.

Login with `requests.Session()`

This example demonstrates how to use requests.Session() to maintain your logged-in state. After logging in, the session object automatically includes the cookies for the subsequent GET request.

import requests

login_url = "http://httpbin.org/post" # Example login endpoint
dashboard_url = "http://httpbin.org/get" # Example page after login

credentials = {
    "username": "my_user",
    "password": "my_password"
}

with requests.Session() as s:
    # First, post login data
    login_response = s.post(login_url, data=credentials)
    print(f"Login Status: {login_response.status_code}")
    print(f"Cookies after login: {s.cookies.get_dict()}")

    # Now, access a protected page using the same session
    protected_page_response = s.get(dashboard_url)
    print(f"Protected Page Status: {protected_page_response.status_code}")
    print("Protected page content snippet:")
    print(protected_page_response.text[:100])

Checking Login Success

How do you know if your bot actually logged in successfully? It's crucial to verify the outcome.

Status Code: A 200 OK often means success, but sometimes redirects happen (e.g., 302 Found).
Redirects: Check response.history to see if you were redirected to a dashboard or profile page.
Page Content: Look for specific text that only appears when logged in (e.g., "Welcome, [username]", a "Logout" button, or absence of login form).

Session Management Check

You're building a bot to log into a website and then navigate to a profile page. Which of the following are true about using requests.Session()?

Recap: User Authentication

In this lesson, we learned how to build bots that can log into websites to access protected content.

We covered inspecting login forms to find the action URL and input field names.
We used requests.post() to send credentials.
Most importantly, we learned to use requests.Session() to manage and persist cookies, allowing our bots to stay logged in and access authenticated content.
Finally, we discussed how to verify successful logins by checking status codes, redirects, and page content.

Frequently asked questions

Is the “Handling User Authentication” lesson free?

Yes — the full text of “Handling User Authentication” is free to read here on the web, and the Web Scraping & Bots course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Web Scraping & Bots course, upgrade to CoddyKit PRO.

What will I learn in “Handling User Authentication”?

Build bots that can log in to websites using credentials, session management, and cookie handling. You practise Web Scraping & Bots with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Web Scraping & Bots?

No prior experience is required. Web Scraping & Bots on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Handling User Authentication” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Web Scraping & Bots lesson?

Yes. Every Web Scraping & Bots lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

← Back to Web Scraping & Bots