Web Crawling
Web crawling is the automated process of systematically navigating and collecting data from web pages. Web crawlers, also known as spiders or bots, access a web page, extract information, and follow hyperlinks to discover more pages, repeating the process across the web.
Also known as: Spidering, web spidering, crawling.
Comparisons
- Web Crawling vs. Web Scraping: Crawling collects data and URLs for indexing, while scraping extracts specific data from pages.
- Web Crawling vs. Data Mining: Crawling gathers web data, while data mining analyzes data to find patterns and insights.
Pros
- Automation: Efficiently gathers large amounts of data for analysis or indexing.
- Up-to-date data: Continuously crawls to keep databases or search indexes current.
- Comprehensive discovery: Finds content across various links and sections of websites.
Cons
- Server strain: Intensive crawling can overload websites if done too aggressively.
- Robots.txt restrictions: Some sites restrict crawling using the robots.txt file.
- Complexity: Developing an effective web crawler can require advanced coding and knowledge of web structures.
Example
A search engine uses a web crawler to scan and index new pages on the Internet to provide updated search results.