PHP can be used to generate dynamic HTML, it can also be used to generate dynamic XML. You can generate XML for other programs to make use of based on forms, database queries, or anything else you can do in PHP. One application for dynamic XML is Rich Site Summary (RSS), a file format for syndicating news sites. You can read an article’s information from a database or from HTML files and emit an XML summary file based on that information
Generating an XML document from a PHP script is simple. Simply change the MIME type of the document, using the header() function, to “text/xml”. To emit the declaration without it being interpreted as a malformed PHP tag, simply echo the line from within PHP code:
echo '<?xml version="1.0" encoding="ISO-8859-1" ?>';
Example to generate RSS document using PHP
<?php
header('Content-Type: text/xml');
echo "xml version=\"1.0\" encoding=\'ISO-8859-1\" ?>";
?>
<!DOCTYPE rss PUBLIC '-//Netscape Communications//DTD RSS 0.91//EN"
"http://my.netscape.com/publish/formats/rss-0.91.dtd">
<rss version="0.91">
<channel>
<?php
// news items to produce RSS for
$items = array(
array(
'title' => "Man Bites Dog",
'link' => "http://www.example.com/dog.php",
'desc' => "Ironic turnaround!"
),
array(
'title' => "Medical Breakthrough!",
'link' => "http://www.example.com/doc.php",
'desc' => "Doctors announced a cure for me."
)
);
foreach($items as $item) {
echo "<item>\n";
echo " <title>{$item['title']}</title>\n";
echo " <link>{$item['link']}</link>\n";
echo " <description>{$item['desc']}</description>\n";
echo " <language>en-us</language>\n";
echo "</item>\n\n";
} ?>
</channel>
</rss>
This script generates output such as the following:
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE rss PUBLIC "-//Netscape Communications//DTD RSS 0.91//EN"
"http://my.netscape.com/publish/formats/rss-0.91.dtd">
<rss version="0.91">
<channel>
<item>
<title>Man Bites Dog</title>
<link>http://www.example.com/dog.php</link>
<description>Ironic turnaround!</description>
<language>en-us</language>
</item>
<item>
<title>Medical Breakthrough!</title>
<link>http://www.example.com/doc.php</link>
<description>Doctors announced a cure for me.</description>
<language>en-us</language>
</item>
</channel>
</rss>