The amount of data Google handles is extraordinary; it processes 200 petabytes daily. This points to the sheer volume of often invaluable data on websites, including business contacts, stock prices, product descriptions, sports team stats, and a lot more. Web Scraping allows you to tap into that.
Web Data Scraping – An overview
Web scraping, also known as data scraping involves collecting various types of data from the internet, be it content, numbers, images, etc.
Web scraping replaces the tedious and error prone process of manual copying and pasting, saving you time and money. Scraped data is usually fed into programs, spreadsheets or databases to be subsequently visualized, processed or used as machine learning training data.
According to Imperva, scraping tools, a.k.a. bots, accounted for about 37% of all internet traffic in 2019. The good bots, i.e. the ones performing applications such as described below comprised 13% of them, while the bad bots - used for spamming, stealing data and other malicious activities - constituted 24%.
Web Scraping Applications
Marketers and researchers use web scraping for lead generation, customer behavior analysis, price intelligence, competitor analysis, monitoring, and more. Following are the common usages of web scraping tools:
Lead generation is essential for businesses since their operations depend on a steady supply of prospective customers. They use web scraping tools to get rich business leads without complicated or expensive inbound campaigns.
People nowadays look for the lowest prices with the best quality. Let's say you are an online seller with high-quality products or services but do not know the optimum price to sell or with what promotion strategy. Price scraping allows you to extract price and other data from your competitor's website in a structured manner. The data can help you to monitor your competitor's pricing and analyze their performance and marketing strategies.
Also known as news scraping, this strategy involves data from online media and social websites. The specific data includes news articles, the latest information, market trends, and any news or information that can affect your business goals and strategies.
As a business owner, you must keep an eye on changing market trends and the latest news. This news often contains crucial public data and information that can benefit your interest; moreover, you can find data from any industry.
Market intelligence is the best way to gain an edge on your competition. Web Scraping allows companies to automate the collection of market intelligence through gathering data from sources all over the web and turning it into actionable insights. You can track prices, monitor trends, and collect customer feedback at scale.
Machine learning engineers need data to train their models on. What better place than the Web for such data. From content classification to natural language processing, a plethora of applications resort to scraping data that the Web offers for free and in large amounts.
Web Scraping Challenges
At first, web scraping may look straightforward, but the fact is not everyone is receptive to strangers trying to access their data; large scale scraping involves data extraction from hundreds/thousands of pages at a rapid rate which has the potential to bring servers down.
When faced with a project involving scraping massive amounts of data, developers need to be cognizant of the following roadblocks:
IP blocking is one of the basic techniques employed by site owners for dealing with scrapers. When the server detects a significant number of requests from the same IP address or when a search robot makes many concurrent queries, blocking is triggered. There is also geolocation-based IP filtering. This occurs when the site is secured against data collection efforts from specified geographical areas. The website will either fully prohibit the IP or restrict its access.
The solution to this is using a proxy network to hide your original IP address. This allows data scraping without getting blocked in most cases. However, some proxy servers, especially those hosted in data centers can be detected with relative ease from their IPs. Residential proxies and Mobile proxies on the other hand, while expensive, are undetectable by IP alone since their IP addresses are those of regular users connecting via their ISP.
It’s also worth noting that when rapidly scraping several pages from the same website, hiding your original IP is only half the work. One also needs to resort to IP rotation to simulate requests coming from different users.
Website owners can use honey traps to catch scrapers using a non-visible link which generally won’t be followed by a real user to get the scraper's IP then block it. Scrapers need to be written with this in mind.
Slow website loading time
Some websites have slow loading times or throttle traffic coming from certain geographies, IPs or when repeated requests are detected. Scrapers must be able to deal with this through proper exception handling, time-spaced repeat attempts and proxy use.
Cookies and Sessions
Some websites require the visitor to log in to access information; and even if login credentials are provided, these websites also require authentication cookies to be present on all requests and to originate from the same IP. Scrapers must therefore support cookies and sticky proxy sessions, i.e. be able to tunnel requests via the same IP when using a rotating proxy.
CAPTCHAs enable humans to be distinguished from robots. For verification, logical problems or character input are given, which people answer rapidly but machines cannot. Several CAPTCHA solvers are currently integrated into scrapers for continuous data collecting, although at the expense of a little slowdown.
Website Layout Changes
Website layout changes can disrupt the web scraping process and hinder the scrapers ability from accessing any of their information. It is therefore imperative to implement website change detection into your web crawlers to deal with sudden alterations in website layout.
General purpose Scraping APIs
Rule-based extraction consists in pulling data from a page while familiar with its html code. Most general purpose scraping APIs can be leveraged to do this since they come with a built-in rule engine which lets developers target specific bits of info inside a page. Tools that offer this include Apify, ScrapingBee and Ujeebu.
Layout and Content Agnostic Scraping APIs
Layout and content agnostic scraping is the process of scraping content from websites without prior knowledge of their layout, html coding conventions or even content type. This relatively new breed of scrapers uses machine learning and sometimes computer vision techniques to detect and extract content without being provided any parsing rules. They don’t perform as well as rule-based scrapers but they provide very good results most of the time, and save considerable amounts of time especially when scraping hundreds and thousands of sites with different layouts and little or no use of semantic tags. Some of these tools include Zyte Automatic Extraction API, Diffbot Extract and our very own Ujeebu Extract.
Scraping Browser Extensions
Some web scraper tools are conveniently available as browser extensions to allow users to scrape the web with a simple login and a few clicks. Some of these include Web Scraper and Data Scraper. A quick search on the Google Chrome store for example will bring up a handful. Please note that some of these also have paying services if you would like to run your scrapers in the cloud as opposed to an open browser window.
Open Source Web Scraping Tools For Developers
When faced with a scraping project, developers can choose from a multitude of open source options. In what follows a list of hand picked tools:
|Scrapy, BeautifulSoup, Selenium||Python|
|Axios, Nightmare, Cheerio, Puppeteer||Node.js|
How To Scrape Legally and Ethically?
While scraping is generally legal, it has ethical and legal ramifications that developers should not ignore. Recent history is full of examples of legal cases contesting the scraping of popular websites. It is therefore paramount to adhere to the boundaries of ethical web scraping to avoid issues. It is strongly recommended to:
- Follow the instructions in the scraped website’s robots.txt
- Abide by the website's terms and conditions
- Ask for permission from the website's owner when doing large scale scraping
- Check for copyright violations: ensure that you do not reuse or republish the scraped data without verifying the website's license or having explicit permission from the data owner
- Don't be greedy; only get the content you need.
Despite being frowned upon by website owners who implement all sorts of mechanisms to protect their content against it, scraping is an essential part of the web ecosystem. After all, were it not for web scraping we wouldn’t have search engines in their current form.
When done correctly and ethically, scraping contributes positively to the state of the Web as an open platform for information exchange.
Scraping data from the Web comes with several challenges. Ujeebu Scrape makes it less of a pain by handling all of the challenges cited above so you can focus on the aspects of your project that matter the most.