Web scraping is an automated way to obtain vast information from websites. It is common to use spreadsheets or databases to store and organize the unstructured data generated from the HTML format.
There are different methods to get data from websites using web scraping.
- What is Web Scraping?
- How do Web Scrapers Work?
- Types of Web Scrapers
- Anti-Scraping Tools and How to Bypass Them?
- IP Rate Limiting
- IP Detection
- Honeypot Traps
- HTTP Request Analysis
- Frequent Website Changes
What is Web Scraping?
To do web scraping, you will need a crawler and a scraper. The crawler follows the links on the internet and scans for relevant content. A scraper is designed to extract data from the internet.
The design of the scraper might change substantially depending on the project’s scale and complexity. This change helps to scrape data more efficiently.
Web scraping can be accomplished via third-party services, APIs, or writing your custom code. For example, many of the world’s most popular websites provide APIs that enable you to access structured data from their databases.
However, some sites do not enable users to access vast volumes of structured data or are not technologically competent.
Therefore, this is the best alternative. Web scraping is the most excellent way to get data from a website in this case.
How do Web Scrapers Work?
Afterward, the scraper can either extract all of a webpage’s data or just a specific portion of it, depending on the user’s preferences.
The user should pick and choose the information they need from the website. Finally, the web scraper will provide users with the data they need.
Most online scrapers will produce data in a CSV or Excel spreadsheet. However, more powerful scrapers will be able to export data in JSON, which can be used to create an API.
Types of Web Scrapers
According to various criteria, there are multiple scrapers, including Self-built or Pre-built Web Scrapers, Browser Extension or Software Web Scrapers, Cloud and Local Web Scrapers.
Self-built Web Scrapers
Creating your own web scrapers is an option, but it requires a high level of technical expertise. You will need to learn much more if you want a more advanced web scraper.
Pre-built Web Scrapers
On the other hand, pre-built web scrapers can be downloaded and launched quickly. You can also adjust the additional features of these.
Browser Extensions Web Scrapers
Browser extensions web scrapers can be used to collect data from the internet. They are simple to use but are also restricted since they are embedded within your browser.
However, web scrapers cannot do anything beyond what your browser is capable of.
Software Web Scrapers
Software web scrapers can be installed on your device. They are indeed more difficult to use than browser web scrapers. However, they also have more advanced features that are not constrained by the capabilities of your browser.
Cloud Web Scrapers
Web scrapers that operate in the cloud or on an off-site server are known as cloud web scrapers.
As they operate in the cloud, your computer can concentrate on other things. Also, scraping data from websites does not need computer resources.
Local Web Scrapers
On the other hand, the Local Web Scraper is a program that runs on your computer and uses local resources. If Web scrapers need more processing power or memory, your device will become slow.
Anti-Scraping Tools and How to Bypass Them?
To achieve the best results, you should focus on well-known and popular sites. However, the process of web scraping gets more complex in these situations.
This is because these websites implement various anti-scraping methods.
There is a lot of data found on websites. Genuine site visitors can use this data to gather details or narrow down their options for purchase.
However, non-legitimate visitors, such as rival websites, might utilize this information to gain an edge. Therefore, keeping their rivals at bay is a primary goal of anti-scraping tools on websites.
Search engine optimizers (webmasters) can detect and block users who are not authorized to access the site’s data using anti-scraping software.
Unfortunately, even the most rigorous anti-scraping measures can be bypassed in some cases.
Let us find out what anti-scraping tools do and how to bypass them.
IP Rate Limiting
Scraping bots often send more queries from one IP address than a human operator would do in the same amount of time. Websites can easily track an IP address’s request volume.
Websites can block an IP address or impose a CAPTCHA test if the volume of requests exceeds a certain threshold.
This is referred to as IP rate limiting. However, there are specific ways to avoid IP rate limiting.
How to Bypass IP Rate Limiting?
There are two methods to bypass IP rate limiting. Limiting the number of web pages scraped at once is one approach.
You can also set delays on purpose if necessary (after reaching the original limit). Using proxy servers and IP address rotation after a given number of queries is another option to bypass IP rate limiting.
Websites can block you depending on the location of your IP address. When a website tailors its content to a user’s location, this form of geolocation block is commonplace.
Other times, websites aim to decrease the volume of non-human visitors they get (for example, crawlers). You can be denied access because of the sort of IP address you are using.
How to Bypass IP Detection?
Use a worldwide proxy network with an extensive range of IPs from various countries and different sorts of IPs. Using this method, you may seem to be a legitimate user in the area you wish to get the data you need.
Security measures such as honeypots try to divert the attention of a hacker away from critical data and resources. Crawlers can be intercepted by the same tools that attackers use.
Mask links are used to entice a particular crawler. To get accurate data, the scraper has to follow such URLs. Crawlers can be identified and blocked via honeypots.
How to Bypass Honeypot Traps?
Find CSS attributes like “display: none” or “visibility: hidden” in the links you click on. This shows that the link is fake and contains no useful information.
HTTP Request Analysis
HTTP headers, client IP address, SSL/TLS version, and supporting TLS ciphers are included in every HTTP request sent from a client to a web server.
For example, by looking at the sequence in which HTTP headers appear, you can determine if the request is coming from a genuine web browser or a script.
Websites can check the signature of a recognized web browser or a CAPTCHA to prohibit requests that do not include these signals.
How to Bypass HTTP Request Analysis?
You can use actual web browsers, such as headless Chrome to replicate HTTP signatures. It is a simple approach widely used to avoid HTTP request inspection. The downside is that web browsers are resource eaters and are very slow.
It is more efficient to mimic browser HTTP request signatures even when utilizing a low-level HTTP request library. This gives the programmed HTTP request the appearance of a genuine web browser while being significantly quicker and more efficient.
However, it is essential to note that this strategy only works when the page content is delivered directly in the initial HTML response and not loaded later via AJAX.
Frequent Website Changes
There are many reasons why a website’s layout might change or get updated. This is usually done to prevent other websites from scraping your content.
Thus, designs can appear in unexpected web page locations, such as sidebars or footers. Even the most popular websites have used this tactic.
How to Bypass?
It is important to note that the crawler you are using must keep up with these changes. This is because the ability to scrape the web is always changing, and your crawler must detect these changes. Keeping track of the number of successful requests in every crawl is a simple way to do this.
You can also keep an eye on the target location by creating a testing procedure for a particular website.
For example, you can access a specific section of the website by using a different URL for each one. You can use this method to determine whether there have been any changes.
Additionally, submitting a small number of queries every 24 hours will ensure that the crawling process does not become slowed down.
With the help of the ideas provided above, you can create a scraper that can go around Captchas and crawl the majority of websites without being blocked by anti-scraping tools.