Parse XML using PHP toolkit expat

Parse XML using PHP toolkit expat
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Author: BUILDER. COM
Now everyone advocates that XML is the best friend of Web developers. With the help of XML, the latter can easily format and display data from almost any data source. However, for dynamic content, well-formatted data is far from ideal. Most Web developers will tell you how to do this without dynamic content on the network today! The question is: "How can I create dynamic content using XML ?"
The answer is to use a dynamic content processing language to parse XML, such as PHP or Perl. Theoretically, such programming languages can exploit XML for various purposes. It is nothing more than a toolkit that can parse XML. James Clark provides an expat toolkit. The expat XML toolkit parses XML in C language, making PHP and XML easy to dance.
PHP is an excellent scripting language designed for the Web. XML indicates the standard of Web content. What a beautiful combination of the two!
Below I will show you a simple example, through which you can describe how to use PHP to parse XML documents into HTML. Then I will introduce some other PHP XML concepts. Parsing XML with PHP is simple, and the operation is intuitive, but the details need to be explained. Once you have mastered the essentials of the application, you will be amazed at how you don't think of bringing them together.
Overview
PHP uses the XML toolkit such as expat to parse XML in C language. The function set of this toolkit is the same as the function set used for Perl XML parsing. In addition, this toolkit is also an event-driven parser. This means that expat treats every XML tag or a new line of code as the starting point of an event, and the event is the trigger of a function. The installation of Expat is very simple. If you are using an Apache Web server, you can find the installation and download guide on the php xml reference page.
The basic task of parsing XML with PHP is as follows: First, create an instance of the XML parser. Then, define the function for processing the trigger event, such as the start or end tag. Then, define the actual meaning of the data processing program. Finally, open the XML file, read the file data, and parse the data. Then close the file and release the XML parser.
You see, as I said, this operation process is nothing special. However, before discussing specific examples, let's take a look at the following warnings:
Expat does not validate XML. This means that as long as the XML file is in the correct format-all elements are nested properly, the start and close labels are correct-it will be parsed. Expat can be used regardless of whether XML complies with the standards or definitions referenced in the XML file header.
Expat converts all XML tags to uppercase letters. If your script is mixed with uppercase and lowercase letters in the tag name and other content, be careful.
PHP is compiled when magic quotes settings are enabled, so complex XML files won't be correctly parsed. If magic quotes is not set by default, you should leave it blank.