There is a thin line between gathering data for your business via web scraping and doing damage to the web by careless crawling and scraping. As a valuable tool for generating powerful insights, web data extraction has become imperative for businesses in this competitive market. However, with great power comes great responsibility. As is the case with most powerful things, web scraping must be used responsibly. We have compiled the best practices that you must follow while scraping websites. Let’s get started with it.
Robots.txt should be the first thing to check when you are planning to scrape a website. Every website would have set some rules on how bots should interact with the site in their robots.txt file. Some websites block bots altogether in their robots file. If that is the case, it is best to leave the site and not attempt to crawl them. Scraping sites that block bots is as unethical as it is illegal. Apart from just blocking, the robots file also specifies a set of rules that they consider as good behaviour on that site, such as areas that are allowed to be crawled, restricted pages, and frequency limits for crawling. You should respect and follow all the rules set by a website while attempting to scrape it.
Web servers are not fail-proof. Any web server will slow down or crash if the load on it exceeds a certain limit up to which it can handle. Sending multiple requests too frequently can result in the website’s server going down or the site becoming too slow to load. This creates a bad user experience for the human visitors on the website which defies the whole purpose of that site. It should be noted that the human visitors are of higher priority for the website than bots. While scraping, you should always hit the website with a reasonable time gap and keep the number of parallel requests in control. This will give the website some breathing space, which it should indeed have.
When the data you require is available from multiple sources on the web, how do you choose between the source websites? Since many websites could sometimes be slow or unreachable, defining the sources for crawling is a crucial task that will also define the quality of data. Ideally, you should look for popular sites where fresh and relevant data gets frequently added. Sites with poor navigation and too many broken links are unreliable sources since crawling them could be a maintenance workload in the long run. Reliable sources can enhance the stability of a web crawling setup. You can check out our article on finding reliable sources for web scraping.
As we discussed above, human visitors should have a great experience while browsing a website. To make sure that a website isn’t slowed down due to a high traffic accounting to humans as well as bots, it is better to schedule your web crawling tasks to run in the off-peak hours. The off-peak hours of the site can be determined by the geo location of where the site’s traffic is from. By scraping during the off-peak hours, you can avoid any possible load you might put on the server during the peak hours. This will also help in significantly improving the speed of the scraping process.
Scraping the web to acquire data is unavoidable in the present scenario. However, you should respect copyright laws while using the scraped data. Using the data for republishing it elsewhere is totally unacceptable and can be considered copyright infringement. While scraping, it is important that you check the source website’s TOS page to be on the safer side.
Patience is something that you will need in abundance if you plan on executing a web scraping project. Due to the ever-changing nature of websites, there is no way to create a one size fits all crawler that will continue to provide you with data for a long time. Maintenance will be a part of your life if you are managing a web crawler yourself. Following these best practices will help you stay away from issues like blocking and legal complications while scraping.