How to make a website with a crawler?

Practice: Traditional crawler starts with the URL of one or several initial web pages and obtains the URL on the initial web pages. In the process of crawling the web page, it constantly extracts new URLs from the current page and puts them in the queue until it meets some stop conditions of the system. The workflow of focused crawler is complex, so it is necessary to filter out links irrelevant to the topic according to certain web page analysis algorithm, keep useful links and put them in URL queue for crawling.

Then, it will select the next URL from the queue according to a certain search strategy, and repeat the above process until it reaches a certain condition of the system. In addition, all the web pages crawled by the crawler will be stored by the system, analyzed and filtered to a certain extent, and an index will be established for later query and retrieval; For focused reptiles, the analysis results obtained in this process may also give feedback and guidance to the subsequent crawling process.

Web crawler (also known as web spider and web robot, often called web chaser in FOAF community) is a program or script that automatically crawls information on the World Wide Web according to certain rules, and has been widely used in the Internet field. Search engines use web crawlers to grab web pages, documents, and even pictures, audio, video and other resources, and organize these information through corresponding indexing techniques to provide search users with queries.