Web scraping seems to be a not so difficult thing to do. Just tell the scraper what you need to find, run it, and enjoy the results. However, the cruel reality is that it’s not that easy. The process of web scraping hides a lot of pitfalls and bottlenecks you won’t even think of if you’re relatively new to all this. Luckily, we went through all the roadblocks and managed to overcome them. And we’re willing to share our experience with you to make your life easier.
Never underestimate the amount of data you will have once the scraping is over. On a large scale, this process generates a lot of information that you need to store somewhere. And it’s better if this place is safe enough to be sure no one will steal the scraped data from you. Also, it will be wise to keep this information not on your local hard drives to avoid issues if the hardware goes down.
So think about renting out a secure remote server that has the capacity to handle all the data you’re working with. Let the disk space be larger than you think you’d need in case the volume of information will be larger than you expect.
All websites get their user interfaces upgraded from time to time. But if you’re working with e-commerce sites, those updates are rather frequent. While the new banner or a button moved slightly to the right don’t seem to be significant for users, the web scraper might crash because it was expecting the structure to be different.
That’s why web scrapers need adjustments approximately once a month to work properly and successfully process websites. And that’s the reason why most businesses outsource web scraping. Web scrapers learn as they process websites. Therefore, if you let the algorithm run without adjustments, it will receive bad training data, and, thus, give you incomplete or wrong results.
Website owners don’t like their resources getting scraped. And they don’t care if you won’t harm them doing it. Not every scraper extracts the data with good intentions on their minds. That’s why you should expect all the websites you’re going to process to have some kind of anti-scraping technologies. All these measurements merely detect and block the activity of bots. So you need your scraper to look less like one.
As a web scraper processes the destination website, it sends a bunch of requests to this server. All the requests are sent from the same IP address because you’re not changing your location every second. Obviously, a real user simply can’t send so many requests within such a short time. That’s how the server can tell it’s dealing with a bot, not a human.
Fortunately, you can hide the fact that it’s your web scraper is working hard for you. To do so you need to use proxies which are basically remote servers or devices you connect to. When being connected to the proxy server, you reroute your scraper to go first to the proxy, and only then to the destination server. Doing that your bot picks up the IP address of the remote proxy server and comes to the target website under it. Thus, the authentic IP address, as well as location and other data, remain hidden by the proxy.
If you set up your network in the way that with each request your scraper uses another IP address, you will bypass most anti-scraping algorithms. You just need to choose the reliable proxy provider who offers only clean and high-quality IP addresses. Infatica is an example of such a provider. Its proxies are very reliable, and the prices are affordable for you to feel comfortable.
We advise you to get residential proxies as they’re the best options for data scraping. They are totally secure because only authorized clients to get to use them. Also, residential proxies are real devices with IP addresses issued by ISPs. Most of the proxy providers offer a rotation system that changes your IP with each request - this will simplify the job for you.
After an unsuccessful war with scrapers website owners came up with a brilliant idea - to place links that the user can’t see but the bot will detect. Often such links have a “display: none” CSS style or just colored with the same hue to blend in with the background. It’s a simple yet very effective trick that can crash your scraper and leave you without the needed data.
Thus, you need to set up the algorithm so that the bot doesn’t check those hidden links. It’s easier to do in the case of CSS style “display: none”. But it’s trickier if the link has the same color as the background. Here you will find an extended guide on such traps.
The main difficulty you will face during web scraping is that website owners try to protect themselves from getting scraped. They come up with new ways to stop bots from processing their pages, and it’s an infinite war that will only get more challenging over time for both sides.
So your task here is to keep an eye on website owners and stay updated on all the latest anti-scraping approaches they develop. Then you should figure out as soon as possible how to bypass these restrictions. Then you can be sure you have a continuous delivery of high-quality data.
If you are just learning web scraping, we recommend you this blog, where you will find detailed guides and useful tips from an experienced developer.