In this post, we’ll discuss the web scraping best practices, and since I believe many of you are thinking about it, I’ll address the elephant in the room right away. Is it legal? Most likely yes.
Scraping sites is generally legal, but within certain reasonable grounds (just keep reading).
Also depends on your geographical location, and since I’m not a genie, I don’t know where you’re at, so I can’t say for sure. Check your local laws, and don’t come complaining if we give some “bad advice,” haha.
Jokes apart, in most places it’s okay; just don’t be an a$$hole about it, and stay away from copyrighted material, personal data, and things behind a login screen.
We recommend following these web scraping best practices:
1. Respect robots.txt
Do you want to know the secret for scraping websites peacefully? Just respect the website’s robots.txt file. This file, located at the root of a website, specifies which pages are allowed to be scraped by bots and which ones are off-limits. Following robots.txt is also important as it can result in the blocking of your IP or legal consequences depending on where you’re at.
2. Set a reasonable crawl rate
To avoid overloading, freezing or crashing of the website servers, control the rate of your requests and incorporate time intervals. In much simpler words, go easy with the crawl rate. To achieve this, you can use Scrapy or Selenium and include delays in the requests.
3. Rotate user agents and IP addresses
Websites are able to identify and block scraping bots by using the user agent string or the IP address. Change the user agents and IP addresses occasionally and use a set of real browsers. Use the user agent string and mention yourself in it to some extent. Your goal is to become undetectable, so make sure to do it right.
4. Avoid scraping behind login pages
Let’s just say that scraping stuff behind a login is generally wrong. Right? Okay? I know many of you will skip that section, but anyway… Try to limit the scraping to public data, and if you need to scrape behind a login, maybe ask for permission. I don’t know, leave a comment on how you’d go about this. Do you scrape things behind a login?
5. Parse and clean extracted data
The data that is scraped is often unprocessed and can contain irrelevant or even unstructured information. Before the analysis, it is required to preprocess the data and clean it up with the use of regex, XPath, or CSS selectors. Do it by eliminating the redundancy, correcting the errors and handling the missing data. Take time to clean it as you need quality to avoid headaches.
6. Handle dynamic content
Most of the websites use JavaScript to generate the content of the page, and this is a problem for traditional scraping techniques. To get and scrape the data that is loaded dynamically, one can use headless browsers like Puppeteer or tools like Selenium. Focus only on the aspects that are of interest to enhance the efficiency.
7. Implement robust error handling
It is necessary to correct errors to prevent program failures caused by network issues, rate limiting, or changes in the website structure. Retry the failed requests, obey the rate limits and, if the structure of the HTML has changed, then change the parsing. Record the mistakes and follow the activities to identify the issues and how you can solve them.
8. Respect website terms of service
Before scraping a website, it is advised to go through the terms of service of the website. Some of them either do not permit scraping or have some rules and regulations to follow. If terms are ambiguous, one should contact the owner of the website to get more information.
9. Consider legal implications
Make sure that you are allowed to scrape and use the data legally, including copyright and privacy matters. It is prohibited to scrape any copyrighted material or any personal information of other people. If your business is affected by data protection laws like GDPR, then ensure that you adhere to them.
10. Explore alternative data collection methods
It is recommended to look for other sources of the data before scraping it. There are many websites that provide APIs or datasets that can be downloaded and this is much more convenient and efficient than scraping. So, check if there are any shortcuts before taking the long road.
11. Implement data quality assurance and monitoring
Identify ways in which you can improve the quality of the scraped data. Check the scraper and the quality of the data on a daily basis to identify any abnormalities. Implement automated monitoring and quality checks to identify and avoid issues.
12. Adopt a formal data collection policy
To make sure that you are doing it right and legally, set up a data collection policy. Include in it the rules, recommendations, and legal aspects that your team should be aware of. It rules out the risk of data misuse and ensures that everyone is aware of the rules.
13. Stay informed and adapt to changes
Web scraping is an active field that is characterized by the emergence of new technologies, legal issues, and websites that are being continuously updated. Make sure that you adopt the culture of learning and flexibility so that you are on the right track.
Wrapping it up!
If you’re going to play with some of the beautiful toys at our disposal (do yourself a favor and look up some Python libraries), then… well, please have some good manners, and also be smart about it if you chose to ignore the first advice.
Here are some of the best practices we talked about:
- Respect robots.txt
- Control crawl rate
- Rotate your identity
- Avoid private areas
- Clean and parse data
- Handle errors efficiently
- Be good, obey the rules
As data becomes increasingly valuable, web scrapers will face the choice:
Respect the robots.txt file, yay or nay? It’s up to you.
Comment below, what are your takes on that?
