A simple PHP class for generating simple RSS feeds.

rss.class.php

<?php

abstract class RSSGenerator{
	
	/** The RSS Feed information */
	protected $title;
	protected $link;
	protected $description;
	protected $language;
	
	/** The function to which all output is passed */
	abstract protected function OutputCallback( $output );
	
	/** Called when the XML version has just been declared */
	abstract protected function PostXMLHeader( );
	
	/** Called when it's time to output the items */
	abstract protected function BuildItems( );
	
	/** Generic builder function for XML tags */
	private function StartXMLTag( $tag , $attributes = array() ){
		$this->OutputCallback( "<$tag" );
		foreach ( $attributes as $Attribute=>$Value ){
			$this->OutputCallback( " " );
			$this->OutputCallback( $Attribute );
			$this->OutputCallback( "=\"" );
			$this->OutputCallback( (string)$Value );
			$this->OutputCallback( "\"" );
		}
		$this->OutputCallback( ">" );
	}
	
	private function EndXMLTag( $tag ){
		$this->OutputCallback( "</$tag>" );
	}
	
	private function BuildXML( $tag, $attributes = array(), $inner ){
		$this->StartXMLTag( $tag, $attribute );
			$this->OutputCallback( $inner );
		$this->EndXMLTag( $tag );
	}
	
	/** Output the XML Header for the RSS feed */
	private function GenerateXMLHeader( ){
		$this->OutputCallback( '<?xml version="1.0" encoding="ISO-8859-1" ?>' );
		$this->PostXMLHeader( );
	}
	
	/** Add a style sheet */
	protected function GenerateXMLStyle( $style ){
		$this->OutputCallback( '<?xml-stylesheet type="text/css" href="'.$style.'" ?>' );
	}
	
	/** RSS feed tags */
	private function StartRSSFeed( ){
		$this->StartXMLTag( "rss" , array( "version"=>"2.0" ) );
		$this->StartXMLTag( "channel" );
	}
	
	private function EndRSSFeed( ){
		$this->EndXMLTag( "channel" );
		$this->EndXMLTag( "rss" );
	}
	
	/** Item tag generator */
	public function Item( $Title, $Link, $Description ){
		$this->StartXMLTag( "item" );
			$this->BuildXML( "title", 		array(), $Title );
			$this->BuildXML( "link", 		array(), $Link );
			$this->BuildXML( "description", array(), "<![CDATA[" . $Description . "]]>" );
		$this->EndXMLTag( "item" );
	}
	
	/** Image tag generator */
	public function Image( $Title, $URL, $Link, $Width, $Height ){
		$this->StartXMLTag( "image" );
			$this->BuildXML( "title", 	array(), $Title );
			$this->BuildXML( "url", 	array(), $URL );
			$this->BuildXML( "link", 	array(), $Link );
			$this->BuildXML( "width", 	array(), $Width );
			$this->BuildXML( "height", 	array(), $Height );
		$this->EndXMLTag( "image" );
	}
	
	public function BuildInformation( ){
		$this->BuildXML( "title", 		array(), $this->title );
		$this->BuildXML( "link", 		array(), $this->link );
		$this->BuildXML( "description", array(), $this->description );
		$this->BuildXML( "language", 	array(), $this->language );
	}
	
	/** Call to generate the feed entirely */
	public function BuildRSS( ){
		$this->GenerateXMLHeader( );
		$this->StartRSSFeed( );
			$this->BuildInformation( );
			$this->BuildItems( );
		$this->EndRSSFeed( );
	}
}

?>