In this article, we’re discussing Web Scraping in detail.
What Is Web Scraping?
Search engines, such as Google, have long used so-called web crawlers or crawlers , which scan the Internet for user-defined terms. Crawlers are special types of bots , which visit one web page after another to generate associations with search terms and categorize them. The first web crawler was created as early as 1993, when the first search engine was introduced – Jumpstation.
Web Scraping: Definition
During the web scraping (from the English scraping = scratching / scraping) are extracted and stored data to analyze web pages or use them elsewhere. Through this web scraping , various types of information are stored: for example, contact information , such as email addresses or phone numbers, or also search terms or URLs . These are stored in local databases or tables.
How Does It Work?
Within scraping there are different modes of operation, although in general there is a difference between automatic and manual scraping . The scraping manually defines the manual copying and pasting information and data, as one who cuts and keeps newspaper articles and only carried out if you want to find and store some specific information.
Specialized software is used depending on the type of web page and the content. Within automatic scraping , there are several ways of proceeding :
- Parser: parsers (or parsers ) are used to convert a text into a new structure. For example, in HTML parsing, the software reads an HTML document and stores the information. A DOM parser uses client-side content rendering in the browser to extract data.
- Bots : a bot is software dedicated to performing certain tasks and automating them. In the case of web harvesting , bots are used to automatically browse web pages and collect data.
- Text: Those with command-line experience can take advantage of Unix’s grep function to search the web for certain terms in Python or Perl. This is a very simple method of extracting data, although it requires more work than using software .
For What Purpose It Is Used?
The web scraping is used for a variety of tasks, for example, to collect contact information or special information very quickly. It is also valuable in relation to financial data: it is possible to read data from an external website, organizing them in tabular form and then analyzing and processing them .
Is Web Scraping Legal?
The scraping is not always legal . First of all, scrappers must take into account the intellectual property rights of websites. The web scraping has very negative consequences for some shopping online and suppliers, for example, if the ranking of your page is affected because of aggregators.
It is not uncommon, therefore, for a company to sue a comparison portal to prevent web scraping . In one of these cases, the Frankfurt Regional High Court ruled in 2009 that an airline should allow scraping by comparative portals because, after all, your information is freely accessible. However, the airline had the possibility of resorting to technical measures to avoid it.
The scraping is legal, therefore, provided that the data collected are freely available to third parties on the web . To guarantee the legality of web scraping , the following must be taken into consideration:
- Observe and comply with intellectual property rights . If the data is protected by these rights, it cannot be published anywhere else.
- The operators of the pages have the right to resort to technical processes to avoid web scraping that cannot be circumvented.
- If, for the use of data, user registration or a contract of use is required , these data may not be used by scraping .
- Hiding of advertising, terms and conditions, or disclaimers through scraping technologies is not allowed .
How Can Web Scraping Be Blocked?
To block scraping , website operators can take different measures. For example, the robots.txt file is used to block search engine bots . Therefore, the scraping machine is also prevented by bots of software . It is also possible to block IP addresses of bots .
Contact details and personal information can be selectively hidden: sensitive data, such as phone numbers, can be provided in image form or as CSS, making scraping difficult of the data. In addition, there are numerous anti – bot payment service providers that can establish a firewall . With Google Search Console it is also possible to set up notifications to inform website operators in case their data is used for scraping .