PHP DOM Parser
The PHP DOM Parser
The PHP DOM parser makes it possible to process XML documents in PHP.
Look at the following XML document fraction:
<?xml version="1.0" encoding="UTF-8"?>
<from>Jani</from>
The DOM sees the XML above as a tree structure:
- Level 1: XML Document
- Level 2: Root element: <from>
- Level 3: Text element: "Jani"
Tip: The DOM Parser is a part of the PHP core. No installation is required!
Load and Output XML
The XML file "note.xml" will be used in the examples below.
We want to initialize the XML parser, load the xml, and output it:
<?php
$xmlDoc = new DOMDocument();
$xmlDoc->load("note.xml");
print $xmlDoc->saveXML();
?>
The output of the code above will be:
Tove Jani Reminder Don't forget me this weekend!
If you select "View source" in the browser window, you will see the following HTML:
<?xml version="1.0" encoding="UTF-8"?>
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
The example above creates a DOMDocument-Object and loads the XML from "note.xml" into it.
Then the saveXML() function puts the internal XML document into a string, so we can output it.
Looping through XML
We want to initialize the XML parser, load the XML, and loop through all elements of the <note> element:
<?php
$xmlDoc = new DOMDocument();
$xmlDoc->load("note.xml");
$x = $xmlDoc->documentElement;
foreach ($x->childNodes AS $item) {
print $item->nodeName . " = " . $item->nodeValue . "<br>";
}
?>
The output of the code above will be:
#text =
to = Tove
#text =
from = Jani
#text =
heading = Reminder
#text =
body = Don't forget me this weekend!
#text =
In the example above you see that there are empty text nodes between each element.
When XML generates, it often contains white-spaces between the nodes. The XML DOM parser treats these as ordinary elements, and if you are not aware of them, they sometimes cause problems.
