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This article shows you how to use crawlers to achieve front-end page rendering in dynamic ip agents, the content is concise and easy to understand, it can definitely brighten your eyes. I hope you can get something through the detailed introduction of this article.

A long time ago, almost all websites were rendered using the back-end, that is, assembling a complete HTML page on the server side, and then returning the complete page to the front end for display. Recently, with the popularity of AJAX technology and the wide application of SPA frameworks such as AngularJS, more and more pages are rendered at the front end.

I wonder if you have heard that front-end rendering is not conducive to SEO compared to back-end rendering, because it is not friendly to web crawlers. The reason is that the front-end rendered page needs to execute JavaScript code (that is, AJAX request) on the browser side to obtain the back-end data before it can be assembled into a complete HTML page.

In view of this kind of situation, there are many solutions, the most commonly used is with the help of Headless browser tools such as PhantomJS and puppeteer, which is equivalent to a browser kernel built into the web crawler to render the crawled page first (execute the Javascript script), and then crawl the page content.

However, to use this kind of technology, it's usually all about using Javascript to develop web crawler tools, which is a bit painful for people like me who are used to writing Python.

Until one day, kennethreitz released the open source project requests-html and saw the sentence FullJavaScriptsupport in the project introduction! I can't help but burst into tears. This is it! Less than three days after the project was released on GitHubs, the number of star reached more than 5000, a sign of its influence.

Why is requests-html so popular?

Almost all people who have written Python will use a HTTP library like requests. It is no exaggeration to say that it is the best HTTP library (regardless of programming languages), and its introduction HTTPRequestsforHumans is well deserved. It is also for this reason that Locust and HttpRunner are all developed based on requests.

Requests-html, is another open source project developed by kennethreitz on the basis of requests, which not only can reuse all the functions of requests, but also realizes the parsing of HTML pages, that is, supporting the implementation of Javascript, and the use of CSS and XPath to extract elements of HTML pages, all of which are very much needed for writing web crawler tools.

In the implementation of Javascript implementation, requests-html did not build its own wheels, but with the help of the open source project pyppeteer. Remember the puppeteer project mentioned earlier, which is the official implementation of NodeAPI; by GoogleChrome while the project pyppeteer is equivalent to the unofficial implementation of puppeteer in Python, with almost all the functions of puppeteer.

After sorting out the above relationship, I believe everyone will have a better understanding of requests-html.

In terms of use, requests-html is also very simple, using almost the same as requests, except for the addition of render functionality.

After executing render (), what is returned is the rendered page content.

The above content is how to use crawlers to achieve front-end page rendering in dynamic ip agents. Have you learned any knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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