Big Website Scraping Tips
When done incorrectly, scraping larger websites can provide a number of challenges.
Larger websites would contain more pages, as well as more data and a higher level of protection. The many years that we’ve spent crawling such vast and complicated websites have taught us a lot, and the following web scraping techniques could be able to help you solve some of your problems.
Here are five web scraping tips to get you started:
1. Cache pages accessed during scraping
When scraping large websites, it is absolutely necessary to save the information that you have already downloaded in a cache. You can do this by using a local storage system. Because of this, you won’t have to reload the webpage even if you have to start from the beginning or if you find that the same page needs to be scraped again while you’re doing your work. It is simple to cache data in a key-value store like Redis, but filesystem caches and database caches are other useful storage alternatives to consider.
2. Take it slow and avoid bombarding the website with several concurrent requests
They will immediately blacklist your IPs if you make a considerable number of simultaneous requests from the same IP address since this would be interpreted as a Denial of Service Attack on their website. Web scraping can be detected using algorithms that are installed on large websites. It is recommended that you sequence your requests in the correct order, one after the other, to give it the appearance of human activity. Oh, but scraping in such a way will take an interminable amount of time. Find the best number of simultaneous requests to a website by balancing the requests and experimenting with different amounts of simultaneous requests while using the average response time of the websites as a guide.
3. Save the URLs you’ve already retrieved
You might want to keep a database or key-value store with a list of the URLs you’ve already retrieved. What would you do if your scraper stopped working after capturing 70% of the website? Without this list of URLs, if you need to finish the remaining 30%, you’ll waste a lot of time and bandwidth. Make sure that this list of URLs is stored in a safe place until such time as you have all of the required information. Additionally, the cache might be integrated with this. You’ll be able to continue scraping in this manner.
4. Divide scraping into several stages
If you break the scraping process up into a number of more manageable steps, it will be both simpler and safer. One example would be to divide the process of scraping a large site into two halves. One for compiling links to the webpages that contain the data you need to scrape, and another for actually downloading the webpages to your computer so that you can execute the scraping.
5. Take only what is necessary
If it’s not necessary to do so, you shouldn’t grab or follow every link. You have the ability to design an appropriate navigation strategy, which will allow the scraper to view only the required pages. There will always be the temptation to get everything, but doing so will merely waste your time, bandwidth, and storage space.
Frequently asked questions:
What is the best way to scrape a dynamic website?
How does large-scale scraping work?
The process of gathering data from a variety of sources is referred to as web scraping on a large scale. At Hir Infotech, we take care of data extraction for virtually all types of dynamic websites, including those with infinite scrolling, dropdowns, log-in authentication, AJAX, and a great deal more.
Can you sell scraped data?
Indeed, something like that does exist. The decision to outsource web scraping services is made by multiple firms frequently, and these companies can provide some really nice payments for more difficult jobs. UpWork, a platform that brings businesses together with independent contractors and facilitates the hiring of those contractors for one-time projects, is an excellent location to get started.
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