Core of PHP4: Zend (Reprinted from Aesop)

Core of PHP4: Zend
Peng Wuxing, Taiwan, wrote the topic "The core of PHP4: Zend". Although written last year, I think it is helpful to have a conceptual understanding of PHP/Zend. So translate it. The first time I learned that the original Zend Engine name was composed of two senior designers, Zeev Suraski and Andi Gutmans, who served as the core development work in PHP.
Author: Peng Wuxing introduced: he has set up huoka Zixun network of Taiwan Cultural University. After graduation, he worked as a network administrator of NEC and a network administrator of BIGLOBE. I also published an article in the Internet space Magazine. he has in-depth research and practical experience in the Internet, especially in the WEB field. at present, I work in Xunda computer for network-related work. author: PHP Bible.
I. Overview:
The name of the Zend Engine is a combination of the names of two senior designers, Zeev Suraski and Andi Gutmans, who work as core developers in PHP. the developer aims to develop a new script execution mechanism, and PHP4 is the first implementation product of the new Zend Engine. In some special test environments, the execution speed of Zend (PHP $) is several to several hundred times faster than that of PHP3 and ASP, this also means that the website's back-end CGI interface is not PHP4? Zend does not belong. (Of course, technology is constantly improving. Maybe a new engine will emerge one day .)
After more than two years of development, the Zend Engine has become a generalized programming environment similar to the VBA function. It not only has the traditional PHP function, but also adds the function of distributed object (COM, and can be executed on different operating platforms. With this potential, the Terminator of VBA is not Zend.
Zend makes the most complete commitment to the session with the biggest defect before PHP3 in PHP4, and adds some future functions, such as CyberCash... and so on.
In the opensource community, PHP/Zend is the best example of the only one that can maintain consistency, but has not yet been regarded as a competitor by Microsoft. It has completely lost ASP behind it and is developing towards the VBA environment. Microsoft only tries its best to deal with Linux and does not notice any threats from PHP/Zend.
System diagram:
The user's browser sends a browser request, and the Web server receives the request.
The Web server finds that PHP requires parsing by the PHP engine (based on the file extension), so it is sent to the Zend Engine of PHP4.
The Zend Engine reads files from the hard disk and sends them to the Zend online Compiler (Run-time Compiler) for literal translation. (Online compilation may be omitted after Zend Compiler is released in the future .)
The online execution unit (Excutor) of the Zend Engine executes the compiled PHP program. When necessary, find the relevant modules to perform cooperative actions (such as XML, IMAP, ODBC ).
Zend organizes the execution results into HTML files and sends them to the Web server.
The Web server sends the results over the network to the user's browser.