Web scraping has become a necessity. For efficient web scraping, we use web bots. However, many websites do not like web scraping and have security measures to detect a web scraping bot. If a website detects a web scraping bot, it can block access or even ban the bot.
In this article, we take a look at the main reasons you may get blocked and try to find out how to overcome those issues.
5 Main Reasons Why You Get Blocked While Scraping
- Trying to Scrape the Web Using One IP Address
- Not Using Rotating User Agents
- Not Making Your Bot More Human
- Training Your Bot to Avoid Honeypot Traps
- Using CAPTCHA-solving Services
Trying to Scrape the Web Using One IP Address
It is accepted that to scrape the web; you need to use a proxy server. However, you will be easily caught if you try to use just one IP address to do your scraping. This is because when a website suspects there are too many requests for information coming from a particular IP address, it tries to block or ban that IP address assuming it is a web scraping attempt.
To overcome this issue, most web scraping bots use a set of IP addresses and rotate requests through different IP addresses. Using rotating IP addresses helps in masking the web scraping attempt.
Many types of proxy servers can be used for rotating IP addresses. However, the best option would be to use residential or mobile proxies. These are real devices connected to the web and can easily pass for genuine users.
Not Using Rotating User Agents
When scraping the web, another reason you could get banned or blocked is for not using a proper user agent. A user agent is a small piece of text that is part of the header of an information request. The user agent has information about the browser that sent the request and the computer or device the request came from besides other details.
If a web bot uses a suspect user agent, it could get blocked or banned from a website. Like using just one IP address for all your web scraping, using just one user agent for all your scraping could also lead to a ban or blocking. One way to overcome this is to use the most common user agents. You can find these by visiting this website.
To overcome the issue of incorrect user agents and prevent your bot from getting blocked, we suggest that you use the most common user agents on a rotating basis to avoid detection and blocking. There are websites where you can get a legal and current list of the most common user agents that can be used for web scraping.
Not Making Your Bot More Human
A web bot used for web scraping is just a program that works at tremendous speeds. Since it is a program that does the same task at breakneck speeds, a website with security protocols in place can detect it very quickly. If a website suspects repetitive and similar requests coming in fast, it will ban or block requests.
To overcome this issue, get your bot to mimic a human. For example, a human browsing a site would perhaps spend time scrolling through the site, maybe click on a few items and similar stuff. Get your web bot to mimic this behavior.
Program your bot to make requests with random intervals between requests. For example, let the bot do some random scrolling and click on a page. Make your bot do random stuff that is not repetitive to avoid detection.
Training Your Bot to Avoid Honeypot Traps
Realizing that bots are used for web scraping, some websites use honeypot traps on their web pages. These are hidden links that a human cannot see but are visible to a bot. If a bot follows one of these hidden links, the website will know it is a bot resulting in an instant block or ban.
To overcome this issue, you could program your bot to avoid following links with CSS properties like “display: none;” or “visibility: hidden;”. If you program your bot to recognize this trap, it will avoid getting blocked or banned.
Using CAPTCHA-solving Services
Some websites display CAPTCHAs instead of web pages if they suspect that an information request is from a suspicious user. A CAPTCHA is a picture or text test that you need to solve before the website shares information. Usually, this test can only be solved by a human. Bots would not be able to get past.
To overcome this issue, serious web scrapers would use the services of CAPTCHA solvers. There are many agencies all over the web that use humans to solve CAPTCHAs. However, using these services can be pretty expensive.
READ | How Can A Simple Software Application Upgrade Your Computer Security?
Parting Thoughts
These are just some of the reasons why you can get blocked while scraping the web. We added workarounds to overcome these issues. We hope this article will get you thinking about how you can do web scraping without getting blocked or banned.
via ©GadgetsBeat.
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