Web Crawler is a bot that downloads the content from the internet and indexes it. The main purpose of this bot is to learn about the different web pages on the internet. This kind of bots is mostly operated by search engines. By applying the search algorithms to the data collected by the web crawlers, search engines can provide the relevant links as the response for the request requested by the user. In this article, let’s discuss how the web crawler is implemented.
Webcrawler is a very important application of the Breadth-First Search Algorithm. The idea is that the whole internet can be represented by a directed graph:
- with vertices -> Domains/ URLs/ Websites.
- edges -> Connections.
Approach: The idea behind the working of this algorithm is to parse the raw HTML of the website and look for other URL in the obtained data. If there is a URL, then add it to the queue and visit them in breadth-first search manner.
Note: This code will not work on an online IDE due to proxy issues. Try to run on your local computer.
Website found: https://www.google.com Website found: https://www.facebook.com Website found: https://www.amazon.com Website found: https://www.microsoft.com Website found: https://www.apple.com
Applications: This kind of web crawler is used to acquire the important parameters of the web like:
- What are the frequently visited websites?
- What are the websites that are important in the network as a whole?
- Useful Information on social networks: Facebook, Twitter… etc.
- Who is the most popular person in a group of people?
- Who is the most important software engineer in a company?
Attention reader! Don’t stop learning now. Get hold of all the important Java and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready.
- Tips and Tricks for Competitive Programmers | Set 2 (Language to be used for Competitive Programming)
- How AngularJS prefixes $ and $$ are used?
- How cookies are used in a website?
- How to know which php.ini file is used ?
- Minimum length of the sub-string whose characters can be used to form a palindrome of length K
- Introduction to Data Structures | 10 most commonly used Data Structures
- 10 Node.js Framework to be used in 2019
- Why “chucknorris” is used as a color in HTML ?
- How to detect which one of the defined font was used in a web page?
- What are the C programming concepts used as Data Structures
- Check if characters of a given string can be used to form any N equal strings
- Elements that are used in head section of HTML page
- All combinations of strings that can be used to dial a number
- isupper() and islower() and their application in C++
- Python counter and dictionary intersection example (Make a string using deletion and rearrangement)
- Substrings starting with vowel and ending with consonants and vice versa
- Design a stack to retrieve original elements and return the minimum element in O(1) time and O(1) space
- Queries to insert, delete one occurrence of a number and print the least and most frequent element
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.