Whether you have heard of the term “web scraping” or not, it’s the method of extracting all the desired data from the internet and storing it in one place.
If you ever copied something from a website and pasted it in a separate document, you did some web scraping. In reality, web scraping can be done on a larger scale, including whole websites and using all their data by different means such as HTTP header referer.
Why Web Scraping Matters
Depending on one’s needs, everyone can scrape the web for different reasons. Here are some of the reasons why web scraping matters:
1. Market Research – usually used by companies selling some products or services. Its sole purpose is to gather information about rival companies, which can be used for dynamic pricing, to alter the price when needed.
2. Brand Growth –to gather some essential data from competitors’ websites to succeed. Even when the brand is successful, web scraping can help retain its success by continuing to cater to customers’ needs.
3. News Monitoring –to distinguish between necessary and unnecessary information from a large pool of news. Therefore, it helps highlight important events.
Challenges of Web Scraping
Even though it sounds fairly easy to do, web scraping also faces some challenges, such as:
1. Complicated Web Structure – since the majority of websites are based on HTML, web designers have a large amount of freedom to choose what the websites look like. Therefore, all of the websites are quite different, which requires different scrapers.
Since the majority of websites are often updated or changed, even a slight change can mean that the previously set scraper won’t be able to function on an updated website.
2. Being Blocked (CAPTCHA, IP Blocking, Geo-blocking) – a simple way of blocking or limiting the access of scrapers is by implementing CAPTCHA. It’s not possible to proceed further to the website before completing it, and since scrapers are unable to do so, their access is limited.
If a website has been visited many times from the same IP address, it can be banned from the website or restricted for a specific period to limit the web scraping.
Geo-blocking also blocks or restricts a user, but not based on the IP address, but the user’s physical location. It’s common for websites that deliberately block specific geographic areas from entering their website.
How to Avoid Scraping Blocks
Scraping blocks are software devices specifically designed to block web scrapers before obtaining any data from the website.
1. Proxy Servers – an easy way to avoid scraping blocks is by using proxy servers to lower the risks of being detected. It means that one can enter a website through a false IP address, masking their real one and avoiding getting caught.
2. Different IP addresses – having various IP addresses and using them randomly helps to avoid scraping blocks successfully. Additionally, it’s recommended that you use proxy servers and different IP addresses hand in hand.
3. Various Scraping Patterns – since web scraping is an automated action, always behaving uniformly, computers can often recognize it. To avoid this, use a couple of random mouse movements and clicks from time to time to make it seem more “human.”
4. Use Headers – to make your web scraping look less suspicious. You can also use headers that are sent from a website when entered from a browser. Simple copying of headers into your code will make it look like the website has been entered from a real browser.
Types of HTTP Headers for Scraping
1. Content-Type – shows the media type of the resource for determining response body type and encoding.
2. Content-Length – indicates the size of the response body or the entity-body.
3. Set-Cookie – a server can send a set-cookie header with a response. The duration of the response can be set, after which the cookie is no longer sent.
1. User-Agent – carries information such as operating system, software and its version, application type, and type of HTML layout (for PC, tablet, or phone).
2. Accept-Language – indicates which languages the client understands and prefers.
3. Accept-Encoding – indicates that the required information can be compressed, so it saves traffic volume.
3. Accept – indicates what type of data format can be returned to the client. However, it must agree with the format of the website.
Referer – HTTP header referer provides the webpage address previously visited before sending the request to the web server, simply put, the last webpage the user was on.
If you want to dig deeper into which HTTP headers you should use and optimize when scraping, read more in this article.
To conclude, web scraping can be useful for numerous reasons, but there are many strategies websites use to block or blacklist web scrapers. So, it’s important to know how to approach each website and avoid being caught. Use the tips mentioned above to scrape through the web without interference!