For example, they can be used to create data-driven tools, like price comparison websites. While there are many cases where web scrapers can be used for evil, they also offer great opportunities. Some just want to build bots that work 24/7 without any manual action from them.Īdditionally, some people scrape data from a website to later sell the scraped information to other companies for marketing purposes. Others want to automate the process of gathering information from websites that have a public API or support screen scraping. Many companies want to know what their competitors are up to and use web scraping as a means to gather this type of information. There are many reasons why somebody would want to scrape information from another website. Bots can also be prevented from accessing a website by restricting users’ IP addresses so scraped data doesn’t come from a single source but many – making it almost impossible for bots to distinguish between human visitors and scrapers. In order to control scrapers, website owners sometimes include specific coding language in their websites that prevents access from unauthorized bots or those that attempt to scrape their data. For this, bots need programming tools that enable them to emulate browsers’ behavior as well as adhere to standard protocols such as HTTP or HTTPS. When they encounter a new page, they read its content and extract specific information as defined by the user. Bots access a website and follow its hypertext structure which is combined of HTML pages. Since most websites are dynamically driven nowadays with dynamically-generated content, it’s almost impossible for humans to automate the extraction process themselves so they have to use bots instead. Data scraped usually gets stored in local databases. A web scraper executes with the help of web crawling programs that mimic browsers to access and communicate with different websites, follow their hypertext structure, and extract data according to predefined parameters. This data can be stored in a structured format for further use. Web scraping (or web harvesting or screen scraping) is the process of automatically extracting data from an online service website.
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