With the development of Internet technology, web crawlers have become an important tool for data capture and processing. When implementing web crawlers, PHP and Selenium are also chosen and applied by more and more developers.
As an open source server-side scripting language, PHP has the characteristics of easy to learn and use, diverse extension libraries and good compatibility. It has become the language of choice for many developers. At the same time, Selenium is an automated testing tool, mainly used to simulate user behavior, test web applications, etc. It can realize Web automated testing and Web data capture.
Web crawlers can be implemented by combining PHP and Selenium. The basic implementation process is: first use PHP to write a program, call Selenium to conduct Web automated testing, simulate user behavior and obtain internal data of the Web page; then perform the required data processing, and finally output the results.
Specifically, the following are some specific applications:
With the continuous innovation of Web page technology, more and more More and more pages present dynamic data, and traditional web crawlers can only obtain static HTML pages. Therefore, Selenium needs to be used to simulate user operations to obtain dynamic data, and then realize data capture. If we need to obtain Baidu's search associated words, we can use Selenium to simulate the user entering search keywords in the input box, and then obtain the associated words displayed below the input box.
Using Selenium automated testing tools can easily realize automatic screenshots of web pages. Call Selenium in the PHP program, perform normal simulation operations on the page that needs to be screenshot, and obtain a complete page screenshot. And the screenshots can be cropped and compressed accordingly to achieve better application effects.
Json data has become one of the most commonly used data formats, and the data of many websites are provided in json format. It is also very convenient to use PHP and Selenium to capture json data. You only need to process the data in Selenium's JavaScript, and then pass the json data to PHP through the return value to complete the data capture.
In short, in the development of web crawlers, the combination of PHP and Selenium can break through traditional limitations and achieve more comprehensive data capture and processing. At the same time, you also need to pay attention to the corresponding usage specifications during application to avoid unnecessary trouble.
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