How To Combat Cookie Session Expiry When Scraping
Web scraping is an increasingly common way to capture information and data to use for making business decisions. It’s a highly effective process, enabling you to automate the process of visiting sites to gather critical information.
However, like most other web applications, you may run into concerns with cookies. Do cookies expire? They do, and it is important to have a method in place to help you get around this while still keeping the process of web scraping fast and efficient.
Try Our Web Scraping API
Proxy rotations, CAPTCHA bypass and more… all taken care of 💪
If you are using web scraping for e-commerce or any other task, you will need a cookie strategy in place. A cookie expiry session notification is then easier to get around. Let’s break down when and how cookies expire and how you can continue to scrape the web without having this limit your efficiencies or processes.
What Are Cookies and How Do They Interact with Web Scraping?
A cookie is a tiny text file stored on the user’s device. It helps to remember key information about the user’s previous browsing activity. Cookies are used for various reasons, including to track browsing habits and to provide users with more personalized results when they visit the same site again.
Overall, cookies can be an important part of web scraping. It allows you to get the information you need. From a website standpoint, though, cookies are important for knowing customers and their activities. For that reason, they can get in the way of web scraping, and they also create a window for the company to capture your IP address as well as to track your web scraping actions. This could lead to shutting down your ability to continue to scrape.
Cookie value control is a must when it comes to scraping. Because they save data, they help companies provide a better experience to the website user and capture information about their habits that could influence their marketing. Here’s the kicker – companies can also use cookies as a way to detect and ultimately block web scraping.
Companies have the ability to monitor the traffic coming into your site. They can detect that if they deem you are using a web scraping application programming interface (or web scraping API). They can also detect web scraping bots and scrapers. If that happens, they shut down access, and ultimately, you have to start over to get access to the site.
There are a few common questions about this. Do cookies expire? Yes, and you also need to know:
- When do cookies expire? Sessions last for the length of time that a browser is open. They are automatically deleted when a user closes the browser or otherwise leaves the app. If you are using session cookies, the expiration time is quite short.
- How long does it take for cookies to expire if they are persistent cookies? Persistent cookies continue to exist even after the app or browser is shut down, while a session expired page will not. It is this persistent cookie that you will need to be concerned about when it comes to combating cookie expiration for web scraping.
- You can learn how to check the session timeout of a website using browser developer tools. This will analyze requests and responses. To see the session timeout setting, go to the Global Settings page and locate the security tab.
Combat Cookie Session Expiry
When you are web scraping, you are likely to encounter cookie session timeouts or session expiry. This becomes an important strategy to keep your sessions effective and moving forward. So, how do you do it?
One of the most common methods is to log in and retrieve a fresh set of cookies programmatically. After a notice of cookie session expiration, you simply log in manually and set up the process again. This method requires you to do this on a regular interval. Doing so will allow your web scraper to always operate with valid session data.
This method works, but it can be labor-intensive. If you are trying to engage in web scraping automation, steps like this slow you down. However, there are other strategies that can help you to get around this process.
HTTP Headers and Cookie Session Lifetime Combating
One route to consider is using HTTP headers. An HTTP Header is a field in the HTTP request or response that provides additional context and metadata about the request or the response. The header will contain case-sensitive names, which might include cache control, date, age, cookie, and so on. This is then followed up with a colon and then the value.
The user or client sends a request that contains the request headers to provide more details to the server. The server then responds with the data that was requested in the structure that fits the specifications you requested in the request header.
When you use a header like this as a component of your web scraping processes, you can create a bit of a “block” for detection. That’s because most website owners will use various strategies and tools to pinpoint when web scraping bots are present and, ultimately, to prevent them from capturing data. There’s no doubt that this becomes necessary since web scraping can slow down the network and cause disruption.
Yet, you still need to get around this. Headers allow you to do so without actually triggering those tools. The browser/client sends your HTTP headers in its request. The server then uses this information to detect web scrapers or false users and blocks them. You can flip this around to use it in your favor.
For example, if you optimize your headers when sending them through your web scraper bot or tool, you mimic the behavior of anyone else – a regular user, not a traditional bot. That means it is less likely that you’ll be found out and more likely that you will continue to capture information and use web scraping for your objectives.
To achieve this objective, you will need to use the right HTTP headers for the job. There are various options that can work in this situation. Some examples include:
User-Agent
This is the most commonly used web scraping header for this task. It identifies the application type, operating system, software vendor, or software version of the requesting software user.
An example of this might be:
user-agent: python-requests/2.22.0
However, it is important to note that this one is not all that effective. It can still be spotted and ultimately blocked. Instead, try this one instead:
user-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.64 Safari/537.36 Edg/101.0.1210.47
Accept-Language
Another option is to use the Accept-Language tool, as it tells the server what language version to tell the tool to use. In situations where language is a factor, that can be an important step. Consider an example like this:
accept-language: en-US,en;q=0.9,it;q=0.8,es;q=0.7
Accept-Encoding
This method, as its name states, tells the server which compression algorithm to use. In many cases, this is done to save on bandwidth for some types of documents. It can also reduce the stress that your web scraping activities create on the servers.
accept-encoding: gzip, deflate, br
Cookies
Another option is cookies, which let the server communicate using small pieces of data, as mentioned. We can also use cookies to identify if the request is coming from a real person or a bot – and that’s what we’re working to combat.
You can use web cookies to mimic the actions of organic behavior, making it seem as if there is no bot involved. By sending the cookies back to the server after every interaction, it is possible to mimic more organic behavior. In short, we are able to inform the server that we are a new user – and that means scraping scripts are less likely to get blacklisted.
Persistent Sessions with Libraries
Another strategy for managing cookies in Python web scraping is to use one of the Python request library tools.
For basic cookie handling with sessions, you can use the requests.Session() object. This will be the foundation for cookie management in Python web scraping. It will automatically handle cookies across multiple requests. This is why it makes it ideal for web scraping. Consider the following script:
import requests
with requests.Session() as session:
# Initial request sets cookies
response = session.get('https://example.com')
# Subsequent requests automatically include cookies
profile = session.get('https://example.com/profile')
In this situation, the session object will maintain a RequestsCookieJar. This will store and then manage the cookies throughout the cookie session lifetime.
In another example, you will need to update this a bit for cookie persistence and storage. Implementing cookie persistence is essential in this situation. Cookies can be saved to files and then reloaded later. Here is a script that shows you this as an example:
import pickle
from requests.cookies import RequestsCookieJar
# Save cookies to file
def save_cookies(session, filename):
cookie_jar = session.cookies
with open(filename, 'wb') as f:
pickle.dump(cookie_jar, f)
# Load cookies from file
def load_cookies(session, filename):
with open(filename, 'rb') as f:
cookies = pickle.load(f)
session.cookies.update(cookies)
When using that method, it allows web scraping to continue from the previous sessions. That means that, in this session timeout example, there is no need to authenticate.
Try Our Web Scraping API
Proxy rotations, CAPTCHA bypass and more… all taken care of 💪
A third strategy is cookie security implementation. Of course, security is a critical component of handling cookies. For this reason, you will need to use HTTPS connections for cookie transmission. There is no way around that. This script shows you an example of how that may apply:
import requests
from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util.retry import Retry
def create_secure_session():
session = requests.Session()
# Force HTTPS usage
session.mount('https://', HTTPAdapter(max_retries=Retry(3)))
# Set secure headers
session.headers.update({
'User-Agent': 'Custom Bot 1.0',
'Accept': 'text/html,application/xhtml+xml',
'Accept-Language': 'en-US,en;q=0.9'
})
return session
Cookie Manipulation and Inspection
In situations where you need to debug and maintain sessions, you can use cookie manipulation and inspection tools. Understanding the cookie contents is essential. With the following script, you can get a detailed cookie examination. It can also aid in troubleshooting any type of cookie expiry session issues or complications that happen during the process.
def inspect_cookies(session):
cookie_dict = session.cookies.get_dict()
for name, value in cookie_dict.items():
cookie = session.cookies._cookies
domain = next(iter(cookie.keys()))
path = next(iter(cookie[domain].keys()))
cookie_info = cookie[domain][path][name]
print(f"Name: {name}")
print(f"Value: {value}")
print(f"Domain: {cookie_info.domain}")
print(f"Secure: {cookie_info.secure}")
print(f"Expires: {cookie_info.expires}")
Advanced Solutions
For those who are looking for more advanced setups, the best route could be to use headless browsers. This includes options like Puppeteer and Selenium. These are far better at creating a more realistic interaction, making it seem like the web scraping bot is actually an organic person doing the work. This process also allows for the session renewals to happen in a more natural way. Ultimately, this can be essential when the site has complex authentication flows. It also applies in situations involving heavy JavaScript use for session handling.
How to Get Help with Managing Web Scraping
When it comes to any type of website monitoring and scraping, remember to implement the most important tool to protect your safety: proxy services. We encourage you to check out how proxies can enhance your overall ability to manage the web scraping you’re engaging in.
The more you know about web scraping using proxies, the more effective your process will be. Take some time to learn more about how Rayobyte can help you with the process. Connect with us today to learn more.
FAQs:
When do cookies expire?
Persistent cookies last longer. They typically expire after a specific date that is set by the website.
How long does it take for cookies to expire?
Cookies will stay on a user’s website until they are set to expire. Session cookies are temporary cookies. These expire as soon as the browser is closed or the application ends. Persistent cookies can last for hours or years.
The information contained within this article, including information posted by official staff, guest-submitted material, message board postings, or other third-party material is presented solely for the purposes of education and furtherance of the knowledge of the reader. All trademarks used in this publication are hereby acknowledged as the property of their respective owners.
