How search engine spiders crawl web page data

When we do website optimization, we all try our best to let search spiders crawl into our own websites, thereby improving the inclusion of web pages. But how do spiders crawl website data? Today, for website ranking optimization, I will share with you how search engine spiders crawl our website data.
 
In the search engine spider system, the queue of URLs to be crawled is the decisive factor. The URLs of the website pages crawled by the spider are arranged in order to form a queue structure. When adjusting the program, a certain URL unit is taken out from the beginning of the queue each time and sent to the web page downloader. In this way, each newly downloaded page contains the previous one. URL unit, the newly loaded page will be appended to the end of the URL queue to be crawled, thus forming a loop to help spiders crawl and capture web page information. So how is the order of page URLs in the URL queue to be crawled determined?
 
First, width optimization traversal strategy
  The width optimization traversal strategy is a simple, easy and relatively primitive traversal method that has been widely used since the emergence of search engine spiders. With the advancement of website optimization technology, many newly proposed crawling strategies are often improved based on this method. However, it is worth noting that this original strategy is a quite effective method, even better than many new crawling strategies. The technology is easier to use, so this method is still preferred by many crawler systems. The order of web page crawling is basically arranged according to the importance of the web page. Its usage is similar to the H tag, important ones are retrieved first, and the priority is clear. In fact, the width-optimized traversal strategy implies some web page optimization-level assumptions.
 
Second, incomplete pagerank strategy
  PageRank is a Google proprietary algorithm used to measure the importance of specific web pages relative to search engine pages. The PageRank algorithm can also be applied to URL optimization-level ranking. But the difference is that PageRank is a holistic algorithm, which means that its calculation results are reliable only after all web pages have been downloaded. When a spider crawls a web page, it can only see part of the page during the operation, so it cannot Get reliable PageRank scores.
 
Third, OPIC strategy (Online Page Importance Computation)
OPIC literally translates as "online page importance calculation" and can be seen as an improvement of the PageRank algorithm. Before the algorithm starts, each website page must give the same cash. Whenever a page P is downloaded, the P page will evenly distribute the cash it has to the following pages according to the link direction, and eventually empty out its cash. . As for the web pages in the URL queue to be crawled, they are sorted according to the amount of money the page has, and web pages with abundant cash are downloaded first. The OPIC strategy is basically the same as the PageRank idea. The difference is that PageRank requires iterative calculations every time, while the OPIC strategy eliminates the iterative process and speeds up the calculation.